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	<title>bioRxiv Channel: The Whitehead Institute</title>
	<link>https://biorxiv.org</link>
	<description>
	This feed contains articles for bioRxiv Channel "The Whitehead Institute"
	</description>

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	<prism:publicationName>bioRxiv</prism:publicationName>
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	<title>bioRxiv</title>
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	<link>https://biorxiv.org</link>
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	<item rdf:about="https://biorxiv.org/cgi/content/short/2022.02.17.480958v1?rss=1">
<title>
<![CDATA[
A statistical approach for identifying primary substrates of ZSWIM8-mediated microRNA degradation in small-RNA sequencing data 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/2022.02.17.480958v1?rss=1"
</link>
<description><![CDATA[
BackgroundOne strategy for identifying targets of a regulatory factor is to perturb the factor and use high-throughput RNA sequencing to examine the consequences. However, distinguishing direct targets from secondary effects and experimental noise can be challenging when confounding signal is present in the background at varying levels.

ResultsHere, we present a statistical modeling strategy to identify microRNAs (miRNAs) that are primary substrates of target-directed miRNA degradation (TDMD) mediated by ZSWIM8. This method uses a bi-beta-uniform mixture (BBUM) model to separate primary from background signal components, leveraging the expectation that primary signal is restricted to upregulation and not downregulation upon loss of ZSWIM8. The BBUM model strategy retained the apparent sensitivity and specificity of the previous ad hoc approach but was more robust against outliers, achieved a more consistent stringency, and could be performed using a single cutoff of false discovery rate (FDR).

ConclusionsWe developed the BBUM model, a robust statistical modeling strategy to account for background secondary signal in differential expression data. It performed well for identifying primary substrates of TDMD and should be useful for other applications in which the primary regulatory targets are only upregulated or only downregulated. The BBUM model, FDR-correction algorithm, and significance-testing methods are available as an R package at https://github.com/wyppeter/bbum.
]]></description>
<dc:creator>Wang, P. Y.</dc:creator>
<dc:creator>Bartel, D. P.</dc:creator>
<dc:date>2022-02-19</dc:date>
<dc:identifier>doi:10.1101/2022.02.17.480958</dc:identifier>
<dc:title><![CDATA[A statistical approach for identifying primary substrates of ZSWIM8-mediated microRNA degradation in small-RNA sequencing data]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2022-02-19</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/2021.04.13.439700v1?rss=1">
<title>
<![CDATA[
Pairing to the microRNA 3' region occurs through two alternative binding modes, with affinity shaped by nucleotide identity as well as pairing position 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/2021.04.13.439700v1?rss=1"
</link>
<description><![CDATA[
MicroRNAs (miRNAs), in association with Argonaute (AGO) proteins, direct repression by pairing to sites within mRNAs. Compared to pairing preferences of the miRNA seed region (nucleotides 2-8), preferences of the miRNA 3' region are poorly understood, due to the sparsity of measured affinities for the many pairing possibilities. We used RNA bind-n-seq with purified AGO2-miRNA complexes to measure relative affinities of >1,000 3'-pairing architectures for each miRNA. In some cases, optimal 3' pairing increased affinity by >500-fold. Some miRNAs had two high-affinity 3'-pairing modes--one of which included additional nucleotides bridging seed and 3' pairing to enable high-affinity pairing to miRNA nucleotide 11. The affinity of binding and the position of optimal pairing both tracked with the occurrence of G or oligo(G/C) nucleotides within the miRNA. These and other results advance understanding of miRNA targeting, providing insight into how optimal 3' pairing is determined for each miRNA.

HIGHLIGHTSO_LIRNA bind-n-seq reveals relative affinities of >1,000 3'-pairing architectures
C_LIO_LITwo distinct 3'-binding modes can enhance affinity, by >500-fold in some instances
C_LIO_LIG and oligo(G/C) residues help define the miRNA 3' segment most critical for pairing
C_LIO_LISeed mismatch identity can influence the contribution of compensatory 3' pairing
C_LI
]]></description>
<dc:creator>McGeary, S. E.</dc:creator>
<dc:creator>Bisaria, N.</dc:creator>
<dc:creator>Bartel, D. P.</dc:creator>
<dc:date>2021-04-14</dc:date>
<dc:identifier>doi:10.1101/2021.04.13.439700</dc:identifier>
<dc:title><![CDATA[Pairing to the microRNA 3' region occurs through two alternative binding modes, with affinity shaped by nucleotide identity as well as pairing position]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2021-04-14</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/2021.01.18.427055v1?rss=1">
<title>
<![CDATA[
The molecular basis of coupling between poly(A)-tail length and translational efficiency 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/2021.01.18.427055v1?rss=1"
</link>
<description><![CDATA[
In animal oocytes and early embryos, mRNA poly(A)-tail length strongly influences translational efficiency (TE), but later in development this coupling between tail length and TE disappears. Here, we elucidate how this coupling is first established and why it disappears. Overexpressing cytoplasmic poly(A)-binding protein (PABPC) in frog oocytes specifically improved translation of short-tailed mRNAs, thereby diminishing coupling between tail length and TE. Thus, coupling requires limiting PABPC, implying that in coupled systems longer-tail mRNAs better compete for limiting PABPC. In addition to expressing excess PABPC, post-embryonic cells had two other properties that prevented strong coupling: terminal-uridylation-dependent destabilization of mRNAs lacking bound PABPC, and a regulatory regime wherein PABPC contributes minimally to TE. Thus, these results revealed three fundamental mechanistic requirements for coupling and defined the context-dependent functions for PABPC, in which this protein promotes TE but not mRNA stability in coupled systems and mRNA stability but not TE in uncoupled systems.
]]></description>
<dc:creator>Bartel, D. P.</dc:creator>
<dc:creator>Xiang, K.</dc:creator>
<dc:date>2021-01-19</dc:date>
<dc:identifier>doi:10.1101/2021.01.18.427055</dc:identifier>
<dc:title><![CDATA[The molecular basis of coupling between poly(A)-tail length and translational efficiency]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2021-01-19</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/2020.12.13.422530v1?rss=1">
<title>
<![CDATA[
A Golgi-localized peptide encoded by the CENP-R transcript provides a valuable tool for live cell imaging 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/2020.12.13.422530v1?rss=1"
</link>
<description><![CDATA[
Prior work has identified signal sequences and motifs that are necessary and sufficient to target proteins to specific subcellular regions and organelles such as the plasma membrane, nucleus, Endoplasmic Reticulum, and mitochondria. In contrast, minimal sequence motifs that are sufficient for Golgi localization remain largely elusive. In this work, we identified a 37 amino acid alternative open reading frame (altORF) within the mRNA of the centromere protein, CENP-R. This altORF peptide localizes specifically to the cytoplasmic surface of the Golgi apparatus. Through mutational analysis, we identify a minimal 10 amino acid sequence and a critical cysteine residue that are necessary and sufficient for Golgi localization. Pharmacological perturbations suggest that this peptide is modified through palmitoylation to promote its localization. Together, our work defines a minimal sequence that is sufficient for Golgi targeting and provide a valuable Golgi marker for live cell imaging.
]]></description>
<dc:creator>Navarro, A. P.</dc:creator>
<dc:creator>Cheeseman, I. M.</dc:creator>
<dc:date>2020-12-13</dc:date>
<dc:identifier>doi:10.1101/2020.12.13.422530</dc:identifier>
<dc:title><![CDATA[A Golgi-localized peptide encoded by the CENP-R transcript provides a valuable tool for live cell imaging]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2020-12-13</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/2021.12.17.473210v1?rss=1">
<title>
<![CDATA[
Dynamic cell cycle-dependent phosphorylation modulates CENP-L-CENP-N centromere recruitment 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/2021.12.17.473210v1?rss=1"
</link>
<description><![CDATA[
The kinetochore is a macromolecular structure that is required to ensure proper chromosome segregation during each cell division. The kinetochore is assembled upon a platform of the 16-subunit Constitutive Centromere Associated Network (CCAN), which is present at centromeres throughout the cell cycle. The nature and regulation of CCAN assembly, interactions, and dynamics required to facilitate changing centromere properties and requirements remain to be fully elucidated. The CENP-LN CCAN sub-complex displays a unique cell cycle-dependent localization behavior, peaking in S phase. Here, we demonstrate that phosphorylation of CENP-L and CENP-N controls CENP-LN complex formation and localization in a cell cycle-dependent manner. Mimicking constitutive phosphorylation of either CENP-L or CENP-N or simultaneously preventing phosphorylation of both proteins prevents CENP-LN localization and disrupts chromosome segregation. Together, our work suggests that cycles of phosphorylation and dephosphorylation are critical for CENP-LN complex recruitment and dynamics at centromeres to enable cell cycle-dependent CCAN reorganization.
]]></description>
<dc:creator>Navarro, A. P.</dc:creator>
<dc:creator>Cheeseman, I. M.</dc:creator>
<dc:date>2021-12-18</dc:date>
<dc:identifier>doi:10.1101/2021.12.17.473210</dc:identifier>
<dc:title><![CDATA[Dynamic cell cycle-dependent phosphorylation modulates CENP-L-CENP-N centromere recruitment]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2021-12-18</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/2021.11.28.470116v1?rss=1">
<title>
<![CDATA[
The phenotypic landscape of essential human genes 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/2021.11.28.470116v1?rss=1"
</link>
<description><![CDATA[
Understanding the basis for cellular growth, proliferation, and function requires determining the contributions of essential genes to diverse cellular processes. Here, we combined pooled CRISPR/Cas9-based functional screening of 5,072 fitness-conferring genes in human cells with microscopy-based visualization of DNA, DNA damage, actin, and microtubules. Analysis of >31 million individual cells revealed measurable phenotypes for >90% of genes. Using multi-dimensional clustering based on hundreds of quantitative phenotypic parameters, we identified co-functional genes across diverse cellular activities, revealing novel gene functions and associations. Pooled live-cell screening of [~]450,000 cell division events for 239 genes further identified functional contributions to chromosome segregation. Our work creates a resource for the phenotypic analysis of core cellular processes and defines the functional landscape of essential human genes.
]]></description>
<dc:creator>Funk, L.</dc:creator>
<dc:creator>Su, K.-C.</dc:creator>
<dc:creator>Feldman, D.</dc:creator>
<dc:creator>Singh, A.</dc:creator>
<dc:creator>Moodie, B.</dc:creator>
<dc:creator>Blainey, P.</dc:creator>
<dc:creator>Cheeseman, I. M.</dc:creator>
<dc:date>2021-11-28</dc:date>
<dc:identifier>doi:10.1101/2021.11.28.470116</dc:identifier>
<dc:title><![CDATA[The phenotypic landscape of essential human genes]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2021-11-28</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/2021.10.24.465552v1?rss=1">
<title>
<![CDATA[
Alternative Cdc20 translational isoforms bypass the spindle assembly checkpoint to control mitotic arrest duration 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/2021.10.24.465552v1?rss=1"
</link>
<description><![CDATA[
Mitotic chromosome segregation defects activate the Spindle Assembly Checkpoint (SAC), which inhibits the APC/C co-activator Cdc20 to induce a prolonged cell cycle arrest. Once errors are corrected, the SAC is silenced thereby allowing anaphase onset and mitotic exit to proceed. However, in the presence of persistent, unresolvable errors, cells can undergo "mitotic slippage", exiting mitosis into a tetraploid G1 state and escaping the cell death that results from a prolonged arrest. The molecular logic that allows cells to balance these dueling mitotic arrest and slippage behaviors remains unclear. Here we demonstrate that human cells modulate their mitotic arrest duration through the presence of conserved, alternative Cdc20 translational isoforms. Translation initiation at downstream start sites results in truncated Cdc20 isoforms that are resistant to SAC-mediated inhibition and promote mitotic exit even in the presence of mitotic perturbations. Targeted molecular changes or naturally-occurring mutations in cancer cells that alter the relative Cdc20 isoform levels or its translational regulatory control modulate both mitotic arrest duration and anti-mitotic drug sensitivity. Our work reveals a critical role for the differential translational regulation of Cdc20 in mitotic arrest timing, with important implications for the diagnosis and treatment of human cancers.
]]></description>
<dc:creator>Tsang, M. J.</dc:creator>
<dc:creator>Cheeseman, I. M.</dc:creator>
<dc:date>2021-10-24</dc:date>
<dc:identifier>doi:10.1101/2021.10.24.465552</dc:identifier>
<dc:title><![CDATA[Alternative Cdc20 translational isoforms bypass the spindle assembly checkpoint to control mitotic arrest duration]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2021-10-24</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/2021.05.17.444558v1?rss=1">
<title>
<![CDATA[
Polarized Dishevelled dissolution and condensation drives embryonic axis specification in oocytes 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/2021.05.17.444558v1?rss=1"
</link>
<description><![CDATA[
The organismal body axes that are formed during embryogenesis are intimately linked to intrinsic asymmetries established at the cellular scale in oocytes [1]. Here, we report an axis-defining event in meiotic oocytes of the sea star Patiria miniata. Dishevelled is a cytoplasmic Wnt pathway effector required for axis development in diverse species [2-4], but the mechanisms governing its function and distribution remain poorly defined. Using time-lapse imaging, we find that Dishevelled localizes uniformly to puncta throughout the cell cortex in Prophase I-arrested oocytes, but becomes enriched at the vegetal pole following meiotic resumption through a dissolution-condensation mechanism. This process is driven by an initial disassembly phase of Dvl puncta, followed by selective reformation of Dvl assemblies at the vegetal pole. Rather than being driven by Wnt signaling, this localization behavior is coupled to meiotic cell cycle progression and influenced by Lamp1+ endosome association and Frizzled receptors pre-localized within the oocyte cortex. Our results reveal a cell cycle-linked mechanism by which maternal cellular polarity is transduced to the embryo through spatially-regulated Dishevelled dynamics.
]]></description>
<dc:creator>Swartz, Z.</dc:creator>
<dc:creator>Tan, T. H.</dc:creator>
<dc:creator>Perillo, M.</dc:creator>
<dc:creator>Fakhri, N.</dc:creator>
<dc:creator>Wessel, G. M.</dc:creator>
<dc:creator>Wikramanayake, A.</dc:creator>
<dc:creator>Cheeseman, I. M.</dc:creator>
<dc:date>2021-05-18</dc:date>
<dc:identifier>doi:10.1101/2021.05.17.444558</dc:identifier>
<dc:title><![CDATA[Polarized Dishevelled dissolution and condensation drives embryonic axis specification in oocytes]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2021-05-18</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/2021.06.15.447736v1?rss=1">
<title>
<![CDATA[
Convergence of case-specific epigenetic alterations identify a confluence of genetic vulnerabilities tied to opioid dependence 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/2021.06.15.447736v1?rss=1"
</link>
<description><![CDATA[
Opioid dependence is a highly heterogeneous disease driven by a variety of genetic and environmental risk factors which have yet to be fully elucidated. We interrogated the effects of opioid dependence on the brain using ChIP-seq to quantify patterns of H3K27 acetylation in dorsolateral prefrontal cortical neurons isolated from 51 opioid-overdose cases and 51 accidental death controls. Among opioid cases, we observed global hypoacetylation and identified 388 putative enhancers consistently depleted for H3K27ac. Machine learning on H3K27ac patterns predicts case-control status with high accuracy. We focus on case-specific regulatory alterations, revealing 81,399 hypoacetylation events, uncovering vast inter-patient heterogeneity. We developed a strategy to decode this heterogeneity based on convergence analysis, which leveraged promoter-capture Hi-C to identify five genes over-burdened by alterations in their regulatory network or "plexus": ASTN2, KCNMA1, DUSP4, GABBR2, ENOX1. These convergent loci are enriched for opioid use disorder risk genes and heritability for generalized anxiety, number of sexual partners, and years of education. Overall, our multi-pronged approach uncovers neurobiological aspects of opioid dependence and captures genetic and environmental factors perpetuating the opioid epidemic.
]]></description>
<dc:creator>Corradin, O.</dc:creator>
<dc:creator>Sallari, R.</dc:creator>
<dc:creator>Hoang, A. T.</dc:creator>
<dc:creator>Kassim, B. S.</dc:creator>
<dc:creator>Ben Hutta, G.</dc:creator>
<dc:creator>Cuoto, L.</dc:creator>
<dc:creator>Quach, B. C.</dc:creator>
<dc:creator>Lovrenert, K.</dc:creator>
<dc:creator>Hays, C.</dc:creator>
<dc:creator>Gryder, B. E.</dc:creator>
<dc:creator>Iskhakova, M.</dc:creator>
<dc:creator>Cates, H.</dc:creator>
<dc:creator>Song, Y.</dc:creator>
<dc:creator>Bartels, C. F.</dc:creator>
<dc:creator>Hancock, D. B.</dc:creator>
<dc:creator>Mash, D. C.</dc:creator>
<dc:creator>Johnson, E. O.</dc:creator>
<dc:creator>Akbarian, S.</dc:creator>
<dc:creator>Scacheri, P. C.</dc:creator>
<dc:date>2021-06-16</dc:date>
<dc:identifier>doi:10.1101/2021.06.15.447736</dc:identifier>
<dc:title><![CDATA[Convergence of case-specific epigenetic alterations identify a confluence of genetic vulnerabilities tied to opioid dependence]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2021-06-16</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/2021.03.24.436774v1?rss=1">
<title>
<![CDATA[
RNA Pol IV has antagonistic parent-of-origin effects on Arabidopsis endosperm 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/2021.03.24.436774v1?rss=1"
</link>
<description><![CDATA[
Gene expression in endosperm - a seed tissue that mediates transfer of maternal resources to offspring - is under complex epigenetic control. We show here that plant-specific RNA Polymerase IV mediates parental control of endosperm gene expression. Pol IV is required for the production of small interfering RNAs that typically direct DNA methylation. We compared small RNAs, DNA methylation, and mRNAs in A. thaliana endosperm from reciprocal heterozygotes produced by crossing wild-type plants to Pol IV mutants. We find that maternally and paternally acting Pol IV have divergent effects on endosperm. Losses of maternal and paternal Pol IV impact sRNAs and DNA methylation at distinct genomic sites. Strikingly, maternally and paternally-acting Pol IV have antagonistic impacts on gene expression at some loci, divergently promoting or repressing endosperm gene expression. Antagonistic parent-of-origin effects have only rarely been described and are consistent with a gene regulatory system evolving under parental conflict.
]]></description>
<dc:creator>Satyaki, P. R. V.</dc:creator>
<dc:creator>Gehring, M.</dc:creator>
<dc:date>2021-03-24</dc:date>
<dc:identifier>doi:10.1101/2021.03.24.436774</dc:identifier>
<dc:title><![CDATA[RNA Pol IV has antagonistic parent-of-origin effects on Arabidopsis endosperm]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2021-03-24</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/2021.03.29.437569v1?rss=1">
<title>
<![CDATA[
Somatic DNA demethylation generates tissue-specific methylation states and impacts flowering time 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/2021.03.29.437569v1?rss=1"
</link>
<description><![CDATA[
Cytosine methylation is a reversible epigenetic modification to DNA. In plants, removal of cytosine methylation is accomplished by the four members of the DME family of 5-methylcytosine DNA glycosylases. Demethylation by DME is critical for seed development. Consequently, determining the function of the entire gene family in somatic tissues by mutant analysis has not been possible. Here, we bypassed the reproductive defects of dme mutants to create somatic quadruple homozygous mutants of the entire DME family. dme; ros1; dml2; dml3 (drdd) leaves exhibit hypermethylated genomes compared to both wild-type plants and rdd triple mutants, indicating functional redundancy among all four demethylases. Targets of demethylation include regions co-targeted by RNA-directed DNA methylation and, surprisingly, CG gene body methylation, indicating dynamic methylation at these little-understood sites. Additionally, many tissue-specific methylation differences are absent in drdd, suggesting a role for active demethylation in generating divergent epigenetic states across wild-type tissues. Furthermore, drdd plants display a striking early flowering phenotype, which is associated with 5 hypermethylation and transcriptional down-regulation of FLOWERING LOCUS C. Active DNA demethylation is therefore required for proper methylation patterning across somatic tissues and defines the epigenetic landscape of both intergenic and coding regions.
]]></description>
<dc:creator>Williams, B. P.</dc:creator>
<dc:creator>Bechen, L. A.</dc:creator>
<dc:creator>Pohlmann, D. A.</dc:creator>
<dc:creator>Gehring, M.</dc:creator>
<dc:date>2021-03-29</dc:date>
<dc:identifier>doi:10.1101/2021.03.29.437569</dc:identifier>
<dc:title><![CDATA[Somatic DNA demethylation generates tissue-specific methylation states and impacts flowering time]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2021-03-29</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/2021.08.30.458106v1?rss=1">
<title>
<![CDATA[
Flanking sequences regulate the toxicity, non-ATG translation, and aggregation of RNA with tandem CAG Repeats 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/2021.08.30.458106v1?rss=1"
</link>
<description><![CDATA[
Nucleotide repeat-expansions cause several neurodegenerative disorders, including Huntingtons disease and spinocerebellar ataxia. The expanded repeat-containing RNA transcribed from the affected loci agglomerate in the nucleus as pathogenic foci. Here we demonstrate that depending on their surrounding sequence context, RNAs with expanded CAG repeats can also undergo nuclear export and aggregate in the cytoplasm. Cytoplasmic aggregation of repeat-containing RNA coincides with several disease hallmarks, including repeat-associated non-AUG (RAN) translation, mislocalization of RNA binding proteins, and cell toxicity. Interestingly, the repeat-containing RNA co-aggregate with RAN translation products. Inhibition of RAN translation prevents cytoplasmic RNA aggregation and also alleviates cell toxicity. Our findings provide a cogent explanation for aberrant cytoplasmic localization of RNA binding proteins and implicate cis-acting flanking sequences in mediating RAN translation and disease.
]]></description>
<dc:creator>Das, M. R.</dc:creator>
<dc:creator>Chang, Y.</dc:creator>
<dc:creator>Saunders, R.</dc:creator>
<dc:creator>Zhang, N.</dc:creator>
<dc:creator>Tomberlin, C.</dc:creator>
<dc:creator>Vale, R. D.</dc:creator>
<dc:creator>Jain, A.</dc:creator>
<dc:date>2021-08-31</dc:date>
<dc:identifier>doi:10.1101/2021.08.30.458106</dc:identifier>
<dc:title><![CDATA[Flanking sequences regulate the toxicity, non-ATG translation, and aggregation of RNA with tandem CAG Repeats]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2021-08-31</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/2021.09.25.461797v1?rss=1">
<title>
<![CDATA[
Single-molecule analysis of specificity and multivalency in binding of short linear substrate motifs to the APC/C 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/2021.09.25.461797v1?rss=1"
</link>
<description><![CDATA[
Robust regulatory signals in the cell often depend on interactions between short linear motifs (SLiMs) and globular proteins. Many of these interactions are poorly characterized because the binding proteins cannot be produced in the amounts needed for traditional methods. To address this problem, we developed a single-molecule off-rate (SMOR) assay based on microscopy of fluorescent ligand binding to immobilized protein partners. We used it to characterize substrate binding to the Anaphase-Promoting Complex/Cyclosome (APC/C), a ubiquitin ligase that triggers chromosome segregation. We find that SLiMs in APC/C substrates (the D box and KEN box) display distinct affinities and specificities for the substrate-binding subunits of the APC/C, and we show that multiple SLiMs in a substrate generate a high-affinity multivalent interaction. The remarkably adaptable substrate-binding mechanisms of the APC/C have the potential to govern the order of substrate destruction in mitosis.
]]></description>
<dc:creator>Hartooni, N.</dc:creator>
<dc:creator>Sung, J.</dc:creator>
<dc:creator>Jain, A.</dc:creator>
<dc:creator>Morgan, D. O.</dc:creator>
<dc:date>2021-09-26</dc:date>
<dc:identifier>doi:10.1101/2021.09.25.461797</dc:identifier>
<dc:title><![CDATA[Single-molecule analysis of specificity and multivalency in binding of short linear substrate motifs to the APC/C]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2021-09-26</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/2021.10.29.466358v1?rss=1">
<title>
<![CDATA[
A phosphoregulated RhoGEF feedback loop tunes cortical flow driven amoeboid migration in vivo 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/2021.10.29.466358v1?rss=1"
</link>
<description><![CDATA[
Cortical flow driven amoeboid migration utilizes friction from retrograde cortical actin flow to generate motion. Many cell types, including cancer cells, can assemble a cortical flow engine to migrate under confinement and low adhesion in vitro, but it remains unclear whether this engine is endogenously utilized in vivo. Moreover, in the context of a changing environment, it is not known how upstream regulation can set in motion and sustain a mutual feedback between flow and polarity. Here, we establish that Drosophila primordial germ cells (PGCs) utilize cortical flow driven amoeboid migration and that flows are oriented by external cues during developmental homing in vivo. The molecular basis of flow modulation is a phosphoregulated feedback loop involving RhoGEF2, a microtubule plus-end tracking RhoA specific RhoGEF, enriched at the rear of PGCs. RhoGEF2 depletion slows and disorganizes cortical flow, reducing migration speed, while RhoGEF2 activation accelerates cortical flow, thereby augmenting myosin II polarity and migration speed. Both perturbations impair PGC pathfinding, suggesting cortical flows must be tuned for accurate guidance. We surprisingly find that RhoGEF2 polarity and activation are independent of upstream canonical G12/13 signaling. Instead, its PDZ domain and conserved RhoA binding residues in its PH domain are required to establish a positive feedback loop that augments its basal activity. Upstream regulation of this feedback loop occurs via AMPK dependent multisite phosphorylation near a conserved EB1 binding SxIP motif, which releases RhoGEF2 from EB1 dependent inhibition. Thus, we reveal cortical flows as versatile, tunable engines for directed amoeboid migration in vivo.
]]></description>
<dc:creator>Lin, B.</dc:creator>
<dc:creator>Luo, J.</dc:creator>
<dc:creator>Lehmann, R.</dc:creator>
<dc:date>2021-10-29</dc:date>
<dc:identifier>doi:10.1101/2021.10.29.466358</dc:identifier>
<dc:title><![CDATA[A phosphoregulated RhoGEF feedback loop tunes cortical flow driven amoeboid migration in vivo]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2021-10-29</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/2021.09.30.462471v1?rss=1">
<title>
<![CDATA[
Bioactive isoprenoids guide migrating germ cells to the embryonic gonad 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/2021.09.30.462471v1?rss=1"
</link>
<description><![CDATA[
Germ cells are essential to sexual reproduction. Across the animal kingdom, extracellular signaling isoprenoids, such as retinoic acids (RAs) in vertebrates and juvenile hormones (JHs) in invertebrates, facilitate multiple processes in the germline lifecycle. Here we investigated the role of these potent signaling molecules in embryonic germ cell migration, using JHs in Drosophila melanogaster as a model system. In contrast to their established endocrine roles during larval and adult germline development, we found that JH signaling acts locally during embryonic development. Using an in vivo biosensor, we found JH signaling is first active near primordial germ cells (PGCs) as they migrate to the developing somatic gonad. Through in vivo and in vitro assays, we found that JHs are both necessary and sufficient for PGC migration. Analysis into the mechanisms of this newly uncovered paracrine JH function revealed that PGC migration was compromised when JHs were reduced or increased, suggesting that specific titers or spatiotemporal JH dynamics are required for robust PGC colonization to the gonad. Compromised PGC migration can impair fertility and cause germ cell tumors in many species, including humans. In mammals, retinoids, a JH-related family of signaling isoprenoids, has many roles in development and reproduction. We found that retinoic acid, like JH, was sufficient to impact PGC migration in vitro. Together, our study reveals a previously unanticipated role of isoprenoids as local effectors of pre-gonadal PGC development and suggests a broadly shared mechanism in PGC migration.

HighlightsO_LIJuvenile hormones (JH) are necessary & sufficient for Primordial Germ Cell (PGC) migration.
C_LIO_LIJH signaling acts directly in and around migrating PGCs prior to its endocrine function.
C_LIO_LICompensatory feedback sensitive to JH receptor function maintains JH homeostasis.
C_LIO_LIJH-like retinoic acids may have similar roles during mammalian germ cell migration.
C_LI
]]></description>
<dc:creator>Barton, L.</dc:creator>
<dc:creator>Sanny, J.</dc:creator>
<dc:creator>Dawson, E. P.</dc:creator>
<dc:creator>Nouzova, M.</dc:creator>
<dc:creator>Noriega, F. G.</dc:creator>
<dc:creator>Stadtfeld, M.</dc:creator>
<dc:creator>Lehmann, R.</dc:creator>
<dc:date>2021-10-01</dc:date>
<dc:identifier>doi:10.1101/2021.09.30.462471</dc:identifier>
<dc:title><![CDATA[Bioactive isoprenoids guide migrating germ cells to the embryonic gonad]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2021-10-01</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/2021.01.21.427703v1?rss=1">
<title>
<![CDATA[
A single cell atlas reveals unanticipated cell type complexity in Drosophila ovaries 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/2021.01.21.427703v1?rss=1"
</link>
<description><![CDATA[
Organ function relies on the spatial organization and functional coordination of numerous cell types. The Drosophila ovary is a widely used model system to study the cellular activities underlying organ function, including stem cell regulation, cell signaling and epithelial morphogenesis. However, the relative paucity of cell type specific reagents hinders investigation of molecular functions at the appropriate cellular resolution.

Here, we used single cell RNA sequencing to characterize all cell types of the stem cell compartment and early follicles of the Drosophila ovary. We computed transcriptional signatures and identified specific markers for nine states of germ cell differentiation, and 23 somatic cell types and subtypes. We uncovered an unanticipated diversity of escort cells, the somatic cells that directly interact with differentiating germline cysts. Three escort cell subtypes reside in discrete anatomical positions, and express distinct sets of secreted and transmembrane proteins, suggesting that diverse micro-environments support the progressive differentiation of germ cells. Finally, we identified 17 follicle cell subtypes, and characterized their transcriptional profiles. Altogether, we provide a comprehensive resource of gene expression, cell type specific markers, spatial coordinates and functional predictions for 34 ovarian cell types and subtypes.
]]></description>
<dc:creator>Slaidina, M.</dc:creator>
<dc:creator>Gupta, S.</dc:creator>
<dc:creator>Lehmann, R.</dc:creator>
<dc:date>2021-01-22</dc:date>
<dc:identifier>doi:10.1101/2021.01.21.427703</dc:identifier>
<dc:title><![CDATA[A single cell atlas reveals unanticipated cell type complexity in Drosophila ovaries]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2021-01-22</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/2021.09.23.461611v1?rss=1">
<title>
<![CDATA[
High-throughput functionalization of the Toxoplasma kinome uncovers a novel regulator of invasion and egress 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/2021.09.23.461611v1?rss=1"
</link>
<description><![CDATA[
Protein kinases regulate fundamental aspects of cell biology in all eukaryotes, making them attractive chemotherapeutic targets in Apicomplexan parasites such as the causative agents of malaria (Plasmodium spp.) and toxoplasmosis (Toxoplasma gondii). However, the precise roles of individual parasite kinases cannot be inferred simply from sequence identity, due to rewiring of signaling pathways and the shifting repertoire of kinases across species. To systematically examine the parasite kinome, we developed a high-throughput (HiT) CRISPR-mediated tagging strategy to endogenously label all predicted cytosolic protein kinases with a synthetic sequence encoding the minimal auxin-inducible degron (mAID) linked to a fluorophore and epitope tag. The system enables the assembly of thousands of tagging vectors from synthetic sequences in a single reaction and the pooled generation of mutants to examine kinase localization and function. We examined the phenotypes associated with kinase knock-down in 1,160 arrayed clones by replica-plating in the presence or absence of auxin and found broad defects across the lytic cycle for 109 clonal isolates, assigning localizations to 39 proteins, and associating 15 kinases within 6 distinct morphological phenotypes. The relative fitness of tagged alleles was also examined by tracking the relative abundance of individual guide RNAs as parasite populations progressed through the lytic cycle, in the presence or absence of auxin. Pooled screening had a high predictive value and differentiated between delayed and acute death. Demonstrating the value of this resource, we identified a novel kinase associated with delayed death as a novel regulator of invasion and egress. We call the previously unstudied kinase Store Potentiating/Activating Regulatory Kinase (SPARK), based on its impact on intracellular Ca2+ stores at key moments during the lytic cycle. Despite having a similar kinase domain to the mammalian PDK1, SPARK lacks the canonical lipid-binding domain and we find no indication SPARK positively regulates other AGC kinases, suggesting a rewiring of signaling pathways to accommodate parasite adaptations. The HiT vector screening system extends the applications of genome-wide screens into complex cellular phenotypes, providing a scalable and versatile platform for the dissection of apicomplexan cell biology.
]]></description>
<dc:creator>Smith, T. A.</dc:creator>
<dc:creator>Lopez-Perez, G. S.</dc:creator>
<dc:creator>Shortt, E.</dc:creator>
<dc:creator>Lourido, S.</dc:creator>
<dc:date>2021-09-24</dc:date>
<dc:identifier>doi:10.1101/2021.09.23.461611</dc:identifier>
<dc:title><![CDATA[High-throughput functionalization of the Toxoplasma kinome uncovers a novel regulator of invasion and egress]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2021-09-24</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/2021.07.21.453261v1?rss=1">
<title>
<![CDATA[
Toxoplasma gondii subverts the host ESCRT machinery for parasite uptake of host cytosolic proteins 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/2021.07.21.453261v1?rss=1"
</link>
<description><![CDATA[
Toxoplasma gondii is a master manipulator capable of effectively siphoning the resources from the host cell for its intracellular subsistence. However, the molecular underpinnings of how the parasite gains resources from its host remain largely unknown. Residing within a non-fusogenic parasitophorous vacuole, the parasite must acquire resources across the limiting membrane of its replicative niche, which is decorated with parasite proteins including those secreted from dense granules. We discovered a role for the Endosomal Sorting Complex Required for Transport (ESCRT) machinery in host cytosolic protein uptake by T. gondii by disrupting host ESCRT function. We identified the transmembrane dense granule protein TgGRA14, which contains motifs homologous to the late domain motifs of HIV-1 Gag, as a candidate for the recruitment of the host ESCRT machinery to the PV membrane. Using an HIV virus-like particle (VLP) release assay, we found that the motif-containing portion of TgGRA14 is sufficient to substitute for HIV Gag late domain to mediate ESCRT-dependent VLP budding. We also show that TgGRA14 is proximal to and interacts with host ESCRT components and other dense granule proteins during infection. Furthermore, analysis of GRA14-deficient parasites revealed a marked reduction in ingestion of a host cytosolic protein compared to WT parasites. Thus, we propose a model in which T. gondii recruits the host ESCRT machinery to the PV where it can interact with TgGRA14 for the internalization of host cytosolic proteins across the PVM. These findings provide new insight into how T. gondii accesses contents of the host cytosol by exploiting a key pathway for vesicular budding and membrane scission.

Author summaryIntracellular pathogens exploit their host to gain the resources necessary to sustain infection; however, precisely how the intracellular parasite Toxoplasma gondii acquires essential nutrients from its host remains poorly understood. Previous work showed that T. gondii is capable of internalizing host derived cytosolic proteins and delivering them to its lysosome-like compartment for degradation. However, the mechanism by which the material is trafficked across the membrane delimiting the replicative vacuole in which the parasite resides remained unclear. Here, we report a role for the parasite effector protein TgGRA14 in the recruitment of the host ESCRT machinery for the uptake of host cytosolic proteins. Important human pathogens have developed strategies for exploiting the host ESCRT machinery for intracellular subsistence. Our study sheds lights on the strategy used by a eukaryotic pathogen in subverting the host ESCRT machinery for the internalization of resources from its host cells.
]]></description>
<dc:creator>Rivera-Cuevas, Y.</dc:creator>
<dc:creator>Mayoral, J.</dc:creator>
<dc:creator>Di Cristina, M.</dc:creator>
<dc:creator>Lawrence, A.-L. E.</dc:creator>
<dc:creator>Olafsson, E. B.</dc:creator>
<dc:creator>Thornhill, D.</dc:creator>
<dc:creator>Waldman, B. S.</dc:creator>
<dc:creator>Ono, A.</dc:creator>
<dc:creator>Sexton, J.</dc:creator>
<dc:creator>Lourido, S.</dc:creator>
<dc:creator>Weiss, L. M.</dc:creator>
<dc:creator>Carruthers, V. B.</dc:creator>
<dc:date>2021-07-21</dc:date>
<dc:identifier>doi:10.1101/2021.07.21.453261</dc:identifier>
<dc:title><![CDATA[Toxoplasma gondii subverts the host ESCRT machinery for parasite uptake of host cytosolic proteins]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2021-07-21</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/2021.08.09.455676v1?rss=1">
<title>
<![CDATA[
A gene-by-gene mosaic of dosage compensation strategies on the human X chromosome 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/2021.08.09.455676v1?rss=1"
</link>
<description><![CDATA[
Researchers have presumed that the "inactive" X chromosome (Xi) has little impact, in trans, on the "active" X (Xa). To test this, we quantified Xi and Xa gene expression in individuals with one Xa and zero to three Xis. Our linear modeling revealed modular Xi and Xa transcriptomes and significant Xi-driven expression changes for 38% (162/423) of expressed X-chromosome genes. By integrating allele-specific analyses, we found that modulation of Xa transcript levels by Xi contributes to many of these Xi-driven changes ([&ge;] 121 genes). By incorporating metrics of evolutionary constraint, we identified 10 X-chromosome genes most likely to drive sex differences in common disease, and sex chromosome aneuploidy syndromes. We conclude that human X chromosomes are regulated both in cis, through Xi-wide transcriptional attenuation, and in trans, through positive or negative modulation of individual Xa genes by Xi. The sum of cis and trans effects differs widely among genes.
]]></description>
<dc:creator>San Roman, A. K.</dc:creator>
<dc:creator>Godfrey, A. K.</dc:creator>
<dc:creator>Skaletsky, H.</dc:creator>
<dc:creator>Bellott, D. W.</dc:creator>
<dc:creator>Groff, A. F.</dc:creator>
<dc:creator>Blanton, L. V.</dc:creator>
<dc:creator>Hughes, J. F.</dc:creator>
<dc:creator>Brown, L.</dc:creator>
<dc:creator>Phou, S.</dc:creator>
<dc:creator>Buscetta, A.</dc:creator>
<dc:creator>Kruszka, P.</dc:creator>
<dc:creator>Banks, N.</dc:creator>
<dc:creator>Dutra, A.</dc:creator>
<dc:creator>Pak, E.</dc:creator>
<dc:creator>Lasutschinkow, P. C.</dc:creator>
<dc:creator>Keen, C.</dc:creator>
<dc:creator>Davis, S. M.</dc:creator>
<dc:creator>Tartaglia, N. R.</dc:creator>
<dc:creator>Samango-Sprouse, C.</dc:creator>
<dc:creator>Muenke, M.</dc:creator>
<dc:creator>Page, D. C.</dc:creator>
<dc:date>2021-08-09</dc:date>
<dc:identifier>doi:10.1101/2021.08.09.455676</dc:identifier>
<dc:title><![CDATA[A gene-by-gene mosaic of dosage compensation strategies on the human X chromosome]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2021-08-09</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/2021.04.21.440828v1?rss=1">
<title>
<![CDATA[
GC-biased gene conversion in X-Chromosome palindromes conserved in human, chimpanzee, and rhesus macaque 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/2021.04.21.440828v1?rss=1"
</link>
<description><![CDATA[
Gene conversion is GC-biased across a wide range of taxa. Large palindromes on mammalian sex chromosomes undergo frequent gene conversion that maintains arm-to-arm sequence identity greater than 99%, which may increase their susceptibility to the effects of GC-biased gene conversion. Here, we demonstrate a striking history of GC-biased gene conversion in 12 palindromes conserved on the X chromosomes of human, chimpanzee, and rhesus macaque. Primate X-chromosome palindrome arms have significantly higher GC content than flanking single-copy sequences. Nucleotide replacements that occurred in human and chimpanzee palindrome arms over the past 7 million years are one-and-a-half times as GC-rich than the ancestral bases they replaced. Using simulations, we show that our observed pattern of nucleotide replacements is consistent with GC-biased gene conversion with a magnitude of 70%, similar to previously reported values based on analyses of human meioses. However, GC-biased gene conversion explains only a fraction of the observed difference in GC content between palindrome arms and flanking sequence, suggesting that additional factors are required to explain elevated GC content in palindrome arms. This work supports a greater than 2:1 preference for GC bases over AT bases during gene conversion, and demonstrates that the evolution and composition of mammalian sex chromosome palindromes is strongly influenced by GC-biased gene conversion.
]]></description>
<dc:creator>Jackson, E. K.</dc:creator>
<dc:creator>Bellott, D. W.</dc:creator>
<dc:creator>Skaletsky, H.</dc:creator>
<dc:creator>Page, D. C.</dc:creator>
<dc:date>2021-04-21</dc:date>
<dc:identifier>doi:10.1101/2021.04.21.440828</dc:identifier>
<dc:title><![CDATA[GC-biased gene conversion in X-Chromosome palindromes conserved in human, chimpanzee, and rhesus macaque]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2021-04-21</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/2021.11.08.467675v1?rss=1">
<title>
<![CDATA[
Krüppel-like factor 4 is required for development and regeneration of germline and yolk cells from somatic stem cells in planarians 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/2021.11.08.467675v1?rss=1"
</link>
<description><![CDATA[
Sexually reproducing animals segregate their germline from their soma. In addition to gamete-producing gonads, planarian and parasitic flatworm reproduction relies on yolk-cell-generating accessory reproductive organs (vitellaria) supporting development of yolkless oocytes. Despite the importance of vitellaria for flatworm reproduction (and parasite transmission), little is known about this unique evolutionary innovation. Here we examine reproductive system development in the planarian Schmidtea mediterranea, in which pluripotent stem cells generate both somatic and germ cell lineages. We show that a homolog of the pluripotency factor Klf4 is expressed in primordial germ cells, presumptive germline stem cells, and yolk-cell progenitors. klf4 knockdown animals fail to specify or maintain germ cells; surprisingly, they also fail to maintain yolk cells. We find that yolk cells display germ-cell-like attributes and that vitellaria are structurally analogous to gonads. In addition to identifying a new proliferative cell population in planarians (yolk cell progenitors) and defining its niche, our work provides evidence supporting the hypothesis that flatworm germ cells and yolk cells share a common evolutionary origin.
]]></description>
<dc:creator>Issigonis, M.</dc:creator>
<dc:creator>Redkar, A.</dc:creator>
<dc:creator>Rozario, T.</dc:creator>
<dc:creator>Khan, U.</dc:creator>
<dc:creator>Mejia-Sanchez, R.</dc:creator>
<dc:creator>Lapan, S.</dc:creator>
<dc:creator>Reddien, P.</dc:creator>
<dc:creator>Newmark, P. A.</dc:creator>
<dc:date>2021-11-08</dc:date>
<dc:identifier>doi:10.1101/2021.11.08.467675</dc:identifier>
<dc:title><![CDATA[Krüppel-like factor 4 is required for development and regeneration of germline and yolk cells from somatic stem cells in planarians]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2021-11-08</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/2021.07.27.453979v1?rss=1">
<title>
<![CDATA[
m6A is required for resolving progenitor identity during planarian stem cell differentiation 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/2021.07.27.453979v1?rss=1"
</link>
<description><![CDATA[
Regeneration requires accurate production of missing cell lineages. Cell production is driven by changes to gene expression, which is shaped by multiple layers of regulation. Here, we find that the ubiquitous mRNA base-modification, m6A, is required for proper cell fate choice and cellular maturation in planarian stem cells (neoblasts). We mapped m6A-enriched regions in 7,600 planarian genes, and found that perturbation of the m6A pathway resulted in progressive deterioration of tissues and death. Using single cell RNA sequencing of >20,000 cells following perturbation of the pathway, we discovered that m6A negatively regulates transcription of histone variants, and that inhibition of the pathway resulted in accumulation of undifferentiated cells throughout the animal in an abnormal transcriptional state. Analysis of >1000 planarian gene expression datasets revealed that the inhibition of the chromatin modifying complex NuRD had almost indistinguishable consequences, unraveling an unappreciated link between m6A and chromatin modifications. Our findings reveal that m6A is critical for planarian stem cell homeostasis and gene regulation in regeneration.
]]></description>
<dc:creator>Dagan, Y.</dc:creator>
<dc:creator>Yesharim, Y.</dc:creator>
<dc:creator>Bonneau, A. R.</dc:creator>
<dc:creator>Schwartz, S.</dc:creator>
<dc:creator>Reddien, P. W.</dc:creator>
<dc:creator>Wurtzel, O.</dc:creator>
<dc:date>2021-07-28</dc:date>
<dc:identifier>doi:10.1101/2021.07.27.453979</dc:identifier>
<dc:title><![CDATA[m6A is required for resolving progenitor identity during planarian stem cell differentiation]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2021-07-28</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/2021.10.12.464111v1?rss=1">
<title>
<![CDATA[
Lineage Recording Reveals the Phylodynamics, Plasticity and Paths of Tumor Evolution 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/2021.10.12.464111v1?rss=1"
</link>
<description><![CDATA[
Tumor evolution is driven by the progressive acquisition of genetic and epigenetic alterations that enable uncontrolled growth, expansion to neighboring and distal tissues, and therapeutic resistance. The study of phylogenetic relationships between cancer cells provides key insights into these processes. Here, we introduced an evolving lineage-tracing system with a single-cell RNA-seq readout into a mouse model of Kras;Trp53(KP)-driven lung adenocarcinoma which enabled us to track tumor evolution from single transformed cells to metastatic tumors at unprecedented resolution. We found that loss of the initial, stable alveolar-type2-like state was accompanied by transient increase in plasticity. This was followed by adoption of distinct fitness-associated transcriptional programs which enable rapid expansion and ultimately clonal sweep of rare, stable subclones capable of metastasizing to distant sites. Finally, we showed that tumors develop through stereotypical evolutionary trajectories, and perturbing additional tumor suppressors accelerates tumor progression by creating novel evolutionary paths. Overall, our study elucidates the hierarchical nature of tumor evolution, and more broadly enables the in-depth study of tumor progression.
]]></description>
<dc:creator>Yang, D.</dc:creator>
<dc:creator>Jones, M. G.</dc:creator>
<dc:creator>Naranjo, S.</dc:creator>
<dc:creator>Rideout, W. M.</dc:creator>
<dc:creator>Min, K. H. J.</dc:creator>
<dc:creator>Ho, R.</dc:creator>
<dc:creator>Wu, W.</dc:creator>
<dc:creator>Replogle, J. M.</dc:creator>
<dc:creator>Page, J. L.</dc:creator>
<dc:creator>Quinn, J. J.</dc:creator>
<dc:creator>Horns, F.</dc:creator>
<dc:creator>Qiu, X.</dc:creator>
<dc:creator>Chen, M. Z.</dc:creator>
<dc:creator>Freed-Pastor, W. A.</dc:creator>
<dc:creator>McGinnis, C. S.</dc:creator>
<dc:creator>Patterson, D. M.</dc:creator>
<dc:creator>Gartner, Z. J.</dc:creator>
<dc:creator>Chow, E. D.</dc:creator>
<dc:creator>Bivona, T. G.</dc:creator>
<dc:creator>Chan, M. M.</dc:creator>
<dc:creator>Yosef, N.</dc:creator>
<dc:creator>Jacks, T.</dc:creator>
<dc:creator>Weissman, J. S.</dc:creator>
<dc:date>2021-10-13</dc:date>
<dc:identifier>doi:10.1101/2021.10.12.464111</dc:identifier>
<dc:title><![CDATA[Lineage Recording Reveals the Phylodynamics, Plasticity and Paths of Tumor Evolution]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2021-10-13</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/2021.12.16.473013v1?rss=1">
<title>
<![CDATA[
Mapping information-rich genotype-phenotype landscapes with genome-scale Perturb-seq 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/2021.12.16.473013v1?rss=1"
</link>
<description><![CDATA[
A central goal of genetics is to define the relationships between genotypes and phenotypes. High-content phenotypic screens such as Perturb-seq (pooled CRISPR-based screens with single-cell RNA-sequencing readouts) enable massively parallel functional genomic mapping but, to date, have been used at limited scales. Here, we perform genome-scale Perturb-seq targeting all expressed genes with CRISPR interference (CRISPRi) across >2.5 million human cells and present a framework to power biological discovery with the resulting genotype-phenotype map. We use transcriptional phenotypes to predict the function of poorly-characterized genes, uncovering new regulators of ribosome biogenesis (including CCDC86, ZNF236, and SPATA5L1), transcription (C7orf26), and mitochondrial respiration (TMEM242). In addition to assigning gene function, single-cell transcriptional phenotypes allow for in-depth dissection of complex cellular phenomena - from RNA processing to differentiation. We leverage this ability to systematically identify the genetic drivers and consequences of aneuploidy and to discover an unanticipated layer of stress-specific regulation of the mitochondrial genome. Our information-rich genotype-phenotype map reveals a multidimensional portrait of gene function and cellular behavior.
]]></description>
<dc:creator>Replogle, J. M.</dc:creator>
<dc:creator>Saunders, R. A.</dc:creator>
<dc:creator>Pogson, A. N.</dc:creator>
<dc:creator>Hussmann, J. A.</dc:creator>
<dc:creator>Lenail, A.</dc:creator>
<dc:creator>Guna, A.</dc:creator>
<dc:creator>Mascibroda, L.</dc:creator>
<dc:creator>Wagner, E. J.</dc:creator>
<dc:creator>Adelman, K.</dc:creator>
<dc:creator>Bonnar, J. L.</dc:creator>
<dc:creator>Jost, M.</dc:creator>
<dc:creator>Norman, T. M.</dc:creator>
<dc:creator>Weissman, J. S.</dc:creator>
<dc:date>2021-12-17</dc:date>
<dc:identifier>doi:10.1101/2021.12.16.473013</dc:identifier>
<dc:title><![CDATA[Mapping information-rich genotype-phenotype landscapes with genome-scale Perturb-seq]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2021-12-17</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/2021.12.22.473893v1?rss=1">
<title>
<![CDATA[
Coupled protein quality control during nonsense mediated mRNA decay 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/2021.12.22.473893v1?rss=1"
</link>
<description><![CDATA[
Translation of mRNAs containing premature termination codons (PTCs) can result in truncated protein products with deleterious effects. Nonsense-mediated decay (NMD) is a surveillance path-way responsible for detecting and degrading PTC containing transcripts. While the molecular mechanisms governing mRNA degradation have been extensively studied, the fate of the nascent protein product remains largely uncharacterized. Here, we use a fluorescent reporter system in mammalian cells to reveal a selective degradation pathway specifically targeting the protein product of an NMD mRNA. We show that this process is post-translational, and dependent on an intact ubiquitin proteasome system. To systematically uncover factors involved in NMD-linked protein quality control, we conducted genome-wide flow cytometry-based screens. Our screens recovered known NMD factors, and suggested a lack of dependence on the canonical ribosome-quality control (RQC) pathway. Finally, one of the strongest hits in our screens was the E3 ubiquitin ligase CNOT4, a member of the CCR4-NOT complex, which is involved in initiating mRNA degradation. We show that CNOT4 is involved in NMD coupled protein degradation, and its role depends on a functional RING ubiquitin ligase domain. Our results demonstrate the existence of a targeted pathway for nascent protein degradation from PTC containing mRNAs, and provide a framework for identifying and characterizing factors involved in this process.
]]></description>
<dc:creator>Inglis, A. J.</dc:creator>
<dc:creator>Guna, A.</dc:creator>
<dc:creator>Merchan, A. G.</dc:creator>
<dc:creator>Pal, A.</dc:creator>
<dc:creator>Esantsi, T. K.</dc:creator>
<dc:creator>Keys, H. R.</dc:creator>
<dc:creator>Frenkel, E. M.</dc:creator>
<dc:creator>Oania, R.</dc:creator>
<dc:creator>Weissman, J. S.</dc:creator>
<dc:creator>Voorhees, R. M.</dc:creator>
<dc:date>2021-12-23</dc:date>
<dc:identifier>doi:10.1101/2021.12.22.473893</dc:identifier>
<dc:title><![CDATA[Coupled protein quality control during nonsense mediated mRNA decay]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2021-12-23</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/2021.08.21.457228v1?rss=1">
<title>
<![CDATA[
Mechanistic basis for the emergence of EPS1 as a catalyst in plant salicylic acid biosynthesis 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/2021.08.21.457228v1?rss=1"
</link>
<description><![CDATA[
Unique to plants in the Brassicaceae family, the production of the plant defense hormone salicylic acid (SA) from isochorismate is accelerated by an evolutionarily young isochorismoyl-glutamate pyruvoyl-glutamate lyase, EPS1, which belongs to the BAHD acyltransferase protein family. Here, we report the crystal structures of apo and substrate-analog-bound EPS1 from Arabidopsis thaliana. Assisted by microsecond molecular dynamics simulations, we uncover a unique pericyclic rearrangement lyase mechanism facilitated by the active site of EPS1. We reconstitute the isochorismate-derived pathway of SA biosynthesis in Saccharomyces cerevisiae, which serves as an in vivo platform that helps identify active-site residues critical for EPS1 activity. This study describes the birth of a new catalyst in plant phytohormone biosynthesis by reconfiguring the ancestral active site of a progenitor enzyme to catalyze alternative reaction.

One sentence summaryBy reconfiguring the active site of a progenitor acyltransferase-fold, EPS1 acquired the unique, evolutionarily new lyase activity that accelerates phytohormone salicylic acid production in Brassicaceae plants.
]]></description>
<dc:creator>Torrens-Spence, M. P.</dc:creator>
<dc:creator>Li, T.</dc:creator>
<dc:creator>Wang, Z.</dc:creator>
<dc:creator>Glinkerman, C. M.</dc:creator>
<dc:creator>Matos, J. O.</dc:creator>
<dc:creator>Wang, Y.</dc:creator>
<dc:creator>Weng, J.-K.</dc:creator>
<dc:date>2021-08-22</dc:date>
<dc:identifier>doi:10.1101/2021.08.21.457228</dc:identifier>
<dc:title><![CDATA[Mechanistic basis for the emergence of EPS1 as a catalyst in plant salicylic acid biosynthesis]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2021-08-22</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/404970v1?rss=1">
<title>
<![CDATA[
Structural basis for independent origins of new catalytic machineries in plant AAAD proteins 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/404970v1?rss=1"
</link>
<description><![CDATA[
Radiation of the plant pyridoxal 5-phosphate (PLP)-dependent aromatic L-amino acid decarboxylase (AAAD) family has yielded an array of paralogous enzymes exhibiting divergent substrate preferences and catalytic mechanisms. Plant AAADs catalyze either the decarboxylation or decarboxylation-dependent oxidative deamination of aromatic L-amino acids to produce aromatic monoamines or aromatic acetaldehydes, respectively. These compounds serve as key precursors for the biosynthesis of several important classes of plant natural products, including indole alkaloids, benzylisoquinoline alkaloids, hydroxycinnamic acid amides, phenylacetaldehyde-derived floral volatiles, and tyrosol derivatives. Here, we present the crystal structures of four functionally distinct plant AAAD paralogs. Through structural and functional analyses, we identify variable structural features of the substrate-binding pocket that underlie the divergent evolution of substrate selectivity toward indole, phenyl, or hydroxyphenyl amino acids in plant AAADs. Moreover, we describe two mechanistic classes of independently arising mutations in AAAD paralogs leading to the convergent evolution of the derived aldehyde synthase activity. Applying knowledge learned from this study, we successfully engineered a shortened benzylisoquinoline alkaloid pathway to produce (S)-norcoclaurine in yeast. This work highlights the pliability of the AAAD fold that allows change of substrate selectivity and access to alternative catalytic mechanisms with only a few mutations.

SignificancePlants biosynthesize their own proteinogenic aromatic L-amino acids, namely L-phenylalanine, L-tyrosine and L-tryptophan, not only for building proteins but also for the production of a plethora of aromatic-amino-acid-derived natural products. Pyridoxal 5-phosphate (PLP)-dependent aromatic L-amino acid decarboxylase (AAAD) family enzymes play important roles in channeling various aromatic L-amino acids into diverse downstream specialized metabolic pathways. Through comparative structural analysis of four functionally divergent plant AAAD proteins together with biochemical characterization and molecular dynamics simulations, we reveal the structural and mechanistic basis for the rich divergent and convergent evolutionary development within the plant AAAD family. Knowledge learned from this study aids our ability to engineer high-value aromatic-L-amino-acid-derived natural product biosynthesis in heterologous chassis organisms.
]]></description>
<dc:creator>Torrens-Spence, M. P.</dc:creator>
<dc:creator>Chiang, Y.-C.</dc:creator>
<dc:creator>Smith, T.</dc:creator>
<dc:creator>Vicent, M. A.</dc:creator>
<dc:creator>Wang, Y.</dc:creator>
<dc:creator>Weng, J.-K.</dc:creator>
<dc:date>2018-08-31</dc:date>
<dc:identifier>doi:10.1101/404970</dc:identifier>
<dc:title><![CDATA[Structural basis for independent origins of new catalytic machineries in plant AAAD proteins]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2018-08-31</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/708065v1?rss=1">
<title>
<![CDATA[
Laboratory culture of the California Sea Firefly Vargula tsujii (Ostracoda: Cypridinidae): Developing a model system for the evolution of marine bioluminescence 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/708065v1?rss=1"
</link>
<description><![CDATA[
Bioluminescence, or the production of light by living organisms via chemical reaction, is widespread across Metazoa. Culture of bioluminescent organisms from diverse taxonomic groups is important for determining the biosynthetic pathways of bioluminescent substrates, which may lead to new tools for biotechnology and biomedicine. Some bioluminescent groups may be cultured, including some cnidarians, ctenophores, and brittle stars, but those use luminescent substrates (luciferins) obtained from their diets, and therefore are not informative for determination of the biosynthethic pathways of the luciferins. Other groups, including terrestrial fireflies, do synthesize their own luciferin, but culturing them is difficult, and the biosynthetic pathway for firefly luciferin remains unclear. An additional independent origin of endogenous bioluminescence is found within ostracods from the family Cypridinidae, which use their luminescence for defense and, in Caribbean species, for courtship displays. Here, we report the first complete life cycle of a luminous ostracod (Vargula tsujii Kornicker & Baker, 1977, the California Sea Firefly) in the laboratory. We also describe the late-stage embryogenesis of Vargula tsujii and discuss the size classes of instar development. We find embryogenesis in V. tsujii ranges from 25-38 days, and this species appears to have five instar stages, consistent with ontogeny in other cypridinid lineages. We estimate a complete life cycle at 3-4 months. We also present the first complete mitochondrial genome for Vargula tsujii. Bringing a luminous ostracod into laboratory culture sets the stage for many potential avenues of study, including learning the biosynthetic pathway of cypridinid luciferin and genomic manipulation of an autogenic bioluminescent system.
]]></description>
<dc:creator>Goodheart, J. A.</dc:creator>
<dc:creator>Minsky, G.</dc:creator>
<dc:creator>Brynjegard-Bialik, M. N.</dc:creator>
<dc:creator>Drummond, M. S.</dc:creator>
<dc:creator>Munoz, J. D.</dc:creator>
<dc:creator>Fallon, T. R.</dc:creator>
<dc:creator>Schultz, D. T.</dc:creator>
<dc:creator>Weng, J.-K.</dc:creator>
<dc:creator>Torres, E.</dc:creator>
<dc:creator>Oakley, T. H.</dc:creator>
<dc:date>2019-07-21</dc:date>
<dc:identifier>doi:10.1101/708065</dc:identifier>
<dc:title><![CDATA[Laboratory culture of the California Sea Firefly Vargula tsujii (Ostracoda: Cypridinidae): Developing a model system for the evolution of marine bioluminescence]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2019-07-21</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/601948v1?rss=1">
<title>
<![CDATA[
PBS3 and EPS1 complete salicylic acid biosynthesis from isochorismate in Arabidopsis 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/601948v1?rss=1"
</link>
<description><![CDATA[
Salicylic acid (SA) is an important phytohormone mediating both local and systemic defense responses in plants. Despite over half a century of research, how plants biosynthesize SA remains unresolved. In Arabidopsis, a major part of SA is derived from isochorismate, a key intermediate produced by the isochorismate synthase (ICS), which is reminiscent of SA biosynthesis in bacteria. Whereas bacteria employ an isochorismate pyruvate lyase (IPL) that catalyzes the turnover of isochorismate to pyruvate and SA, plants do not contain an IPL ortholog and generate SA from isochorismate through an unknown mechanism. Combining genetic and biochemical approaches, we delineated the SA biosynthetic pathway downstream of isochorismate in Arabidopsis. We show that PBS3, a GH3 acyl adenylase-family enzyme important for SA accumulation, catalyzes ATP- and Mg2+-dependent conjugation of L-glutamate primarily to the 8-carboxyl of isochorismate and yields the key SA biosynthetic intermediate isochorismoyl-glutamate A. Moreover, EPS1, a BAHD acyltransferase-family protein with previously implicated role in SA accumulation upon pathogen attack, harbors a noncanonical active site and an unprecedented isochorismoyl-glutamate A pyruvoyl-glutamate lyase (IPGL) activity that produces SA from the isochorismoyl-glutamate A substrate. Together, PBS3 and EPS1 form a two-step metabolic pathway to produce SA from isochorismate in Arabidopsis, which is distinct from how SA is biosynthesized in bacteria. This study closes a major knowledge gap in plant SA metabolism and would help develop new strategies for engineering disease resistance in crop plants.
]]></description>
<dc:creator>Torrens-Spence, M. P.</dc:creator>
<dc:creator>Bobokalonova, A.</dc:creator>
<dc:creator>Carballo, V.</dc:creator>
<dc:creator>Glinkerman, C. M.</dc:creator>
<dc:creator>Pluskal, T.</dc:creator>
<dc:creator>Shen, A.</dc:creator>
<dc:creator>Weng, J.-K.</dc:creator>
<dc:date>2019-04-07</dc:date>
<dc:identifier>doi:10.1101/601948</dc:identifier>
<dc:title><![CDATA[PBS3 and EPS1 complete salicylic acid biosynthesis from isochorismate in Arabidopsis]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2019-04-07</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/498352v1?rss=1">
<title>
<![CDATA[
Ribosomal DNA and the rDNA-binding protein Indra mediate non-random sister chromatid segregation in Drosophila male germline stem cells 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/498352v1?rss=1"
</link>
<description><![CDATA[
Although considered to be exact copies of each other, sister chromatids can segregate non-randomly in some cases. For example, sister chromatids of the X and Y chromosomes segregate non-randomly during asymmetric division of male germline stem cells (GSCs) in D. melanogaster. Here we identify that the ribosomal DNA (rDNA) loci, which are located on the X and Y chromosomes, and an rDNA-binding protein, Indra, are required for non-random sister chromatid segregation (NRSS). We provide the evidence that NRSS is a mechanism by which GSCs recover rDNA copy number, which occurs through unequal sister chromatid exchange, counteracting the spontaneous copy number loss that occurs during aging. Our study reveals an unexpected role for NRSS in maintaining germline immortality through maintenance of a vulnerable genomic element, rDNA.

One Sentence SummaryrDNA copy number maintenance by non-random sister chromatid segregation contributes to germline immortality in Drosophila
]]></description>
<dc:creator>Watase, G.</dc:creator>
<dc:creator>Yamashita, Y.</dc:creator>
<dc:date>2018-12-16</dc:date>
<dc:identifier>doi:10.1101/498352</dc:identifier>
<dc:title><![CDATA[Ribosomal DNA and the rDNA-binding protein Indra mediate non-random sister chromatid segregation in Drosophila male germline stem cells]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2018-12-16</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/2021.07.12.451825v1?rss=1">
<title>
<![CDATA[
The retrotransposon R2 maintains Drosophila ribosomal DNA repeats 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/2021.07.12.451825v1?rss=1"
</link>
<description><![CDATA[
Ribosomal DNA (rDNA) loci contain the hundreds of tandemly repeated copies of ribosomal RNA genes needed to support cellular viability. This repetitiveness makes it highly susceptible to copy number (CN) loss, threatening multi-generational maintenance of rDNA. How this threat is counteracted to avoid extinction of the lineage has remained unclear. Here, we show that the rDNA-specific retrotransposon R2 is essential for rDNA CN maintenance in the Drosophila male germline, despite the perceived disruptive nature of transposable elements. Depletion of R2 led to defective rDNA CN maintenance, causing a decline in fecundity over generations and eventual extinction. This study reveals that active retrotransposons can provide a benefit to their hosts, contrary to their reputation as genomic parasites, which may contribute to their widespread success throughout taxa.

One Sentence SummaryThe retrotransposon R2 initiates restoration of ribosomal DNA copies to trans-generationally maintain essential locus.
]]></description>
<dc:creator>Nelson, J. O.</dc:creator>
<dc:creator>Slicko, A.</dc:creator>
<dc:creator>Yamashita, Y. M.</dc:creator>
<dc:date>2021-07-12</dc:date>
<dc:identifier>doi:10.1101/2021.07.12.451825</dc:identifier>
<dc:title><![CDATA[The retrotransposon R2 maintains Drosophila ribosomal DNA repeats]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2021-07-12</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/2021.04.16.440167v1?rss=1">
<title>
<![CDATA[
Defective satellite DNA clustering into chromocenters underlies hybrid incompatibility in Drosophila 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/2021.04.16.440167v1?rss=1"
</link>
<description><![CDATA[
Although rapid evolution of pericentromeric satellite DNA repeats is theorized to promote hybrid incompatibility (HI)(1-4), how divergent repeats affect hybrid cells remains poorly understood. Recently, we demonstrated that sequence-specific DNA-binding proteins cluster satellite DNA from multiple chromosomes into  chromocenters, thereby bundling chromosomes to maintain the entire genome in a single nucleus(5, 6). Here we show that ineffective clustering of divergent satellite DNA in the cells of Drosophila hybrids results in chromocenter disruption, associated micronuclei formation and tissue atrophy. We further demonstrate that previously identified HI factors trigger chromocenter disruption and micronuclei in hybrids, linking their function to a conserved cellular process. Together, we propose a unifying framework that explains how the widely observed satellite DNA divergence between closely related species can cause reproductive isolation.
]]></description>
<dc:creator>Jagannathan, M.</dc:creator>
<dc:creator>Yamashita, Y. M.</dc:creator>
<dc:date>2021-04-16</dc:date>
<dc:identifier>doi:10.1101/2021.04.16.440167</dc:identifier>
<dc:title><![CDATA[Defective satellite DNA clustering into chromocenters underlies hybrid incompatibility in Drosophila]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2021-04-16</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/2021.04.07.438888v1?rss=1">
<title>
<![CDATA[
me31B regulates stem cell homeostasis by preventing excess dedifferentiation in the Drosophila male germline. 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/2021.04.07.438888v1?rss=1"
</link>
<description><![CDATA[
Tissue-specific stem cells maintain tissue homeostasis by providing a continuous supply of differentiated cells throughout the life of organisms. Differentiated/differentiating cells can revert back to a stem cell identity via dedifferentiation to help maintain the stem cell pool beyond the lifetime of individual stem cells. Although dedifferentiation is important to maintain the stem cell population, it is speculated to underlie tumorigenesis. Therefore, this process must be tightly controlled. Here we show that a translational regulator me31B plays a critical role in preventing excess dedifferentiation in the Drosophila male germline: in the absence of me31B, spermatogonia (SGs) dedifferentiate into germline stem cells (GSCs) at a dramatically elevated frequency. Our results show that the excess dedifferentiation is likely due to misregulation of nos, a key regulator of germ cell identity and GSC maintenance. Taken together, our data reveal negative regulation of dedifferentiation to balance stem cell maintenance with differentiation.
]]></description>
<dc:creator>Jensen, L.</dc:creator>
<dc:creator>Venkei, Z.</dc:creator>
<dc:creator>Watase, G.</dc:creator>
<dc:creator>Bisai, B.</dc:creator>
<dc:creator>Pletcher, S.</dc:creator>
<dc:creator>Lee, C.-Y.</dc:creator>
<dc:creator>Yamashita, Y. M.</dc:creator>
<dc:date>2021-04-09</dc:date>
<dc:identifier>doi:10.1101/2021.04.07.438888</dc:identifier>
<dc:title><![CDATA[me31B regulates stem cell homeostasis by preventing excess dedifferentiation in the Drosophila male germline.]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2021-04-09</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/2021.12.08.471297v1?rss=1">
<title>
<![CDATA[
Long Noncoding RNA RROL Provides Chromatin Scaffold for MYC-WDR82 Interaction to Impact Lipid Metabolism and Tumor Cell Growth in Multiple Myeloma 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/2021.12.08.471297v1?rss=1"
</link>
<description><![CDATA[
Long noncoding RNAs (lncRNA) can drive the tumorigenesis and be susceptible to therapeutic intervention. To define the landscape of therapeutically actionable lncRNA dependencies in multiple myeloma (MM), we coupled our extensive lncRNA transcriptomic profile with lncRNA targeted CRISPR interference viability screen and identified RNA Regulator of Lipogenesis (RROL) as a leading lncRNA dependency in MM. RROL shares its origin with the microRNA locus MIR17HG, however supports the proliferation and survival of MM cells in a microRNA- and DROSHA- independent manner. We found that RROL provides a chromatin scaffold for the functional interaction between c-MYC and WDR82 to promote the regulation of the lipogenic pathways via the transcriptional control of the rate-limiting enzyme ACC1 in MM cells. Inhibition of RROL with clinically applicable antisense molecules disrupts its transcriptional and functional activities causing potent anti-tumor effects both in vitro and in vivo in two pre-clinical animal models. This study establishes lncRNA RROL as a therapeutically actionable dependency with a unique mechanism of action in support of myeloma cell growth.
]]></description>
<dc:creator>Morelli, E.</dc:creator>
<dc:creator>Fulciniti, M.</dc:creator>
<dc:creator>Samur, M. K.</dc:creator>
<dc:creator>Ribeiro, C. F.</dc:creator>
<dc:creator>Wert-Lamas, L.</dc:creator>
<dc:creator>Henninger, J. E.</dc:creator>
<dc:creator>Gulla, A.</dc:creator>
<dc:creator>Aktas-Samur, A.</dc:creator>
<dc:creator>Todoerti, K.</dc:creator>
<dc:creator>Talluri, S.</dc:creator>
<dc:creator>Park, W. D.</dc:creator>
<dc:creator>Federico, C.</dc:creator>
<dc:creator>Scionti, F.</dc:creator>
<dc:creator>Amodio, N.</dc:creator>
<dc:creator>Bianchi, G.</dc:creator>
<dc:creator>Johnstone, M.</dc:creator>
<dc:creator>Liu, N.</dc:creator>
<dc:creator>Gramegna, D.</dc:creator>
<dc:creator>Russo, N. A.</dc:creator>
<dc:creator>Lin, C.</dc:creator>
<dc:creator>Tai, Y.-T.</dc:creator>
<dc:creator>Neri, A.</dc:creator>
<dc:creator>Chauhan, D.</dc:creator>
<dc:creator>Hideshima, T.</dc:creator>
<dc:creator>Shammas, M.</dc:creator>
<dc:creator>Tassone, P.</dc:creator>
<dc:creator>Gryaznov, S.</dc:creator>
<dc:creator>Young, R.</dc:creator>
<dc:creator>Anderson, K. C.</dc:creator>
<dc:creator>Novina, C.</dc:creator>
<dc:creator>Loda, M.</dc:creator>
<dc:creator>Munshi, N. C.</dc:creator>
<dc:date>2021-12-09</dc:date>
<dc:identifier>doi:10.1101/2021.12.08.471297</dc:identifier>
<dc:title><![CDATA[Long Noncoding RNA RROL Provides Chromatin Scaffold for MYC-WDR82 Interaction to Impact Lipid Metabolism and Tumor Cell Growth in Multiple Myeloma]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2021-12-09</prism:publicationDate>
<prism:section></prism:section>
</item>
</rdf:RDF>
