Members of the tristetraprolin (TTP) family of CCCH tandem zinc finger proteins can bind directly to AU-rich elements in mRNAs and promote transcript deadenylation and decay. The yeast Schizosaccharomyces pombe expresses a single TTP family member, Zfs1p, that has been linked to the mating response pathway and septum formation. We showed previously that Zfs1p can bind to and promote the destabilization of AU-rich element-containing transcripts. In this study, we identified additional target transcripts by comparing transcript levels in wild type and zfs1 mutant yeast, using deep sequencing and microarray approaches. We also used direct RNA sequencing to determine the locations of the polyA tails in both wild type and mutant strains, and to confirm the presence of potential Zfs1p target sequences within the mRNA. These studies identified a set of transcripts containing potential Zfs1p binding sites that accumulated significantly in the zfs1 mutants; a subset of these turned over more slowly in the zfs1 mutant strain, and bound directly to Zfs1p in co-immunoprecipitations. One apparent direct target encodes the transcription factor Cbf12p, which is known to increase cell-cell adhesion and flocculation when over-expressed. Studies of zfs1 and cbf12 double mutants demonstrated that the increased flocculation seen in zfs1 mutants is due, at least in part, to a direct effect on the turnover of cbf12 mRNA, leading in turn to changes in the levels of its transcriptionally regulated genes. These data suggest that Zfs1p can both directly and indirectly regulate the levels of transcripts involved in cell-cell adhesion in this species.
Posttranscriptional regulation of cell-cell interaction protein-encoding transcripts by Zfs1p in Schizosaccharomyces pombe.
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View SamplesThis SuperSeries is composed of the SubSeries listed below.
Pausing of RNA polymerase II disrupts DNA-specified nucleosome organization to enable precise gene regulation.
Specimen part
View SamplesControl of RNA transcription is critical for the development and homeostasis of all organisms, and can occur at multiple steps of the transcription cycle, including RNA polymerase II (Pol II) recruitment, initiation, promoter-proximal pausing, and elongation. That Pol II accumulates on many promoters in metazoans implies that steps other than Pol II recruitment are rate-limiting and regulated 1-6. By integrating genome-wide Pol II chromatin immunoprecipition (ChIP) and Global Run-On (GRO) genomic data sets from Drosophila cells, we examined critical features of Pol II near promoters. The accumulation of promoter-proximal polymerase is widespread, occurring on 70% of active genes; and unlike elongating Pol II within the body of genes, promoter Pol II are held paused by factors like NELF, unable to transcribe unless nuclei are treated with strong detergent. Notably, we find that the vast majority of promoter-proximal Pol II detected by ChIP are paused, thereby identifying the biochemical nature of this rate-limiting step in transcription. Finally, we demonstrate that Drosophila promoters do not have the upstream divergent Pol II that is seen so broadly and prominently on mammalian promoters. We postulate this is a consequence of Drosophila's extensive use of directional core promoter sequence elements, which contrasts with mammals' lack of directional elements and prevalence of CpG island core promoters. In support of this idea, we show that the fraction of mammalian promoters containing a TATA box core element is dramatically depleted of upstream divergent transcription. Overall design: Comparison of multiple GRO-seq data sets
Defining the status of RNA polymerase at promoters.
Cell line, Treatment, Subject
View SamplesMetazoan transcription is controlled through either coordinated recruitment of transcription machinery to the gene promoter, or subsequently, through regulated pausing of RNA polymerase II (Pol II) in early elongation. We report that a key difference between genes that use these distinct regulatory strategies lies in the chromatin architecture specified by their DNA sequences. Pol II pausing is prominent at highly-regulated genes whose sequences inherently disfavor nucleosome formation within the gene, but favor nucleosomal occlusion of the promoter. Pausing of polymerase maintains these genes in an active state by inhibiting the formation of repressive promoter chromatin. In contrast, promoters of housekeeping genes that lack paused Pol II are deprived of nucleosomes regardless of polymerase binding, but show higher nucleosome occupancy downstream. Our results suggest that the default chromatin state of a gene instructs its regulation, and that highly-regulated promoters have evolved to encourage competition between nucleosomes and paused Pol II for promoter occupancy.
Pausing of RNA polymerase II disrupts DNA-specified nucleosome organization to enable precise gene regulation.
Specimen part
View SamplesOur results indicate that oxidation of TAF10 by LOXL2 induces its release from its promoters, leading to a block in TFIID-dependent gene transcription. Since TFIID complex is crucial for the expression of Nanog, Klf4, Sox2 and Oct4 and for maintaining the pluripotent state of embryonic stem cells, TAF10 oxidation by LOXL2 leads to inactivation of the pluripotency genes and a loss of pluripotent capacity in embryonic stem cells. Moreover, in vivo results demonstrate an essential role of LOXL2 in neural differentiation during zebrafish development: in the absence of LOXL2 the neural progenitor gene Sox2 is aberrantly overexpressed and neural differentiation is impaired.
LOXL2 Oxidizes Methylated TAF10 and Controls TFIID-Dependent Genes during Neural Progenitor Differentiation.
Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Revealing a human p53 universe.
Specimen part, Subject
View SamplesGene expression analysis of the p53 response in PHA-stimulated human T-lymphocytes treated ex vivo with either Doxorubicin, Nutlin-3, or DMSO
Revealing a human p53 universe.
Specimen part, Subject
View SamplesThe generation of induced pluripotent stem cells (iPSCs) from differentiated cells following forced expression of Oct4, Klf4, Sox2 and c-Myc (OKSM) is slow and inefficient, suggesting that transcription factors have to overcome somatic barriers that resist cell fate change. Here, we performed an ubiased serial shRNA enrichment screen to identify novel repressors of somatic cell reprogramming into iPSCs. This effort uncovered the sumoylation effector protein Sumo2 as one of the strongest roadblocks to iPSC formation. Depletion of Sumo2 both enhances and accelerates reprogramming, yielding transgene-independent, chimera-competent iPSCs after as little as 36 hours of OKSM expression. We further show that the Sumo2 pathway acts independently of exogenous c-Myc expression and in parallel with small molecule enhancers of reprogramming. Critically, suppression of SUMO2 also promotes the generation of human iPSCs. Together, our results reveal sumoylation as a crucial post-transcriptional mechanism that resists the acquisition of pluripotency from fibroblasts using defined factors.
A Serial shRNA Screen for Roadblocks to Reprogramming Identifies the Protein Modifier SUMO2.
Sex, Specimen part, Time
View SamplesMuscle denervation due to injury, disease or aging results in impaired motor function. Restoring neuromuscular communication requires axonal regrowth and regeneration of neuromuscular synapses. Muscle activity inhibits neuromuscular synapse regeneration. The mechanism by which muscle activity regulates regeneration of synapses is poorly understood. Dach2 and Hdac9 are activity-regulated transcriptional co-repressors that are highly expressed in innervated muscle and suppressed following muscle denervation. Here, we report that Dach2 and Hdac9 inhibit regeneration of neuromuscular synapses. Importantly, we identified Myog and Gdf5 as muscle-specific Dach2/Hdac9-regulated genes that stimulate neuromuscular regeneration in denervated muscle. Interestingly, Gdf5 also stimulates presynaptic differentiation and inhibits branching of regenerating neurons. Finally, we found that Dach2 and Hdac9 suppress miR206 expression, a microRNA involved in enhancing neuromuscular regeneration. Overall design: RNAseq on innervated and 3 day denervated adult soleus muscle from wildtype mice is compared with that from 3 day denervated soleus muscle from Dach2/Hdac9 deleted mice to identify Dach2/Hdac9-regulated genes.
Dach2-Hdac9 signaling regulates reinnervation of muscle endplates.
No sample metadata fields
View SamplesWe sought to obtain gene signature specific of high oxidative phsophorylation function.
Chemotherapy-Resistant Human Acute Myeloid Leukemia Cells Are Not Enriched for Leukemic Stem Cells but Require Oxidative Metabolism.
Cell line, Treatment
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