Schizosaccharomyces pombe
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ABSTRACT:
PROVIDER: PRJNA98743 | ENA |
REPOSITORIES: ENA
Similar Datasets
Project description:Accumulation of RNA on chromatin disrupts heterochromatic silencing
| PRJNA369032 | ENA
Project description:Spt6 is a conserved factor, critically required for several transcription and chromatin related processes. We now show that Spt6 and its binding partner, Iws1, are required for heterochromatic silencing in Schizosaccharomyces pombe. Our studies demonstrate that Spt6 is required for silencing of all heterochromatic loci and that an spt6 mutant has an unusual combination of heterochromatic phenotypes compared to previously studied silencing mutants. Unexpectedly, we find normal nucleosome positioning over heterochromatin and normal levels of histone H3K9 dimethylation. However, we also find greatly reduced levels of H3K9 trimethylation, elevated levels of H3K14 acetylation, and reduced recruitment of several silencing factors. Our evidence suggests that Spt6 plays a role at both the transcriptional and post-transcriptional levels; in an spt6 mutant, RNA polymerase II (RNAPII) occupancy at the pericentric regions is only modestly increased, while production of small interfering RNAs (siRNAs) is lost. Taken together, our results suggest that Spt6 is required for multiple steps in heterochromatic silencing by controlling chromatin, transcriptional, and post-transcriptional processes.
2011-10-20 | E-MTAB-738 | biostudies-arrayexpress
Project description:Small RNA loading licenses Argonaute for assembly into a transcriptional silencing complex
| PRJNA273446 | ENA
Project description:In the fission yeast Schizosaccharomyces pombe, the RNA interference (RNAi) pathway is required to generate small interfering RNAs (siRNAs) that mediate heterochromatic silencing of centromeric repeats. Here we demonstrate that RNAi also functions to repress genomic elements other than constitutive heterochromatin. Using DamID (DNA adenine methyltransferase identification) we show that Dcr1 and Rdp1 physically associate with some euchromatic genes, non-coding RNA (ncRNA) genes, and retrotransposon long terminal repeats (LTRs), and that this association is independent of the Clr4 histone methyltransferase. Physical association of RNAi with chromatin is sufficient to trigger a silencing response but not to assemble heterochromatin. The mode of silencing at the newly identified RNAi targets is consistent with a co-transcriptional gene silencing model as proposed earlier and functions with trace amounts of siRNAs. We anticipate that similar mechanisms could also be operational in other eukaryotes.
2010-09-25 | GSE24360 | GEO
Project description:RNAi promotes heterochromatic silencing through replication-coupled release of RNA pol II (RNA seq)
| PRJNA154563 | ENA
Project description:RNAi promotes heterochromatic silencing through replication-coupled release of RNA pol II (ChIP-seq)
| PRJNA154613 | ENA
Project description:The RNA-induced transcriptional silencing complex is targeted to chromatin exclusively via base-pairing interactions with nascent transcripts
| PRJNA345512 | ENA
Project description:Epigenetic gene silencing plays a critical role in regulating gene expression and contributes to organismal development and cell fate acquisition in eukaryotes. In fission yeast, Schizosaccharomyces pombe, heterochromatin-associated gene silencing is known to be mediated by RNA processing pathways including RNA interference (RNAi) and a 3’-5’ exoribonuclease complex exosome. Here, we report a new RNA-processing pathway that contributes to epigenetic gene silencing and assembly of heterochromatin mediated by 5’-3’ exoribonuclease Dhp1/Xrn2. Dhp1 mutation causes defective gene silencing both at peri-centromeric regions and at the silent mating type locus. Intriguingly, mutation of either one of two well-characterized Dhp1-interacting proteins, the Din1 pyrophosphohydrolase or the Rhn1 transcription termination factor, does not show silencing defects at the main heterochromatic regions. Dhp1 is essential in the sequential steps of establishing silencing in a manner independent of both RNAi and the exosome. Genomic and genetic analysis suggest that Dhp1 is involved in post-transcriptional silencing of repetitive regions through its catalytic activity. Our study is the first investigation into an unexpected role of Dhp1/Rat1/Xrn2 in chromatin-based silencing. These results elucidate how various RNA-processing pathways, acting together or independently, contribute to epigenetic regulation of the eukaryotic genome.
2016-01-28 | GSE77290 | GEO
Project description:Epigenetic gene silencing plays a critical role in regulating gene expression and contributes to organismal development and cell fate acquisition in eukaryotes. In fission yeast, Schizosaccharomyces pombe, heterochromatin-associated gene silencing is known to be mediated by RNA processing pathways including RNA interference (RNAi) and a 3’-5’ exoribonuclease complex exosome. Here, we report a new RNA-processing pathway that contributes to epigenetic gene silencing and assembly of heterochromatin mediated by 5’-3’ exoribonuclease Dhp1/Xrn2. Dhp1 mutation causes defective gene silencing both at peri-centromeric regions and at the silent mating type locus. Intriguingly, mutation of either one of two well-characterized Dhp1-interacting proteins, the Din1 pyrophosphohydrolase or the Rhn1 transcription termination factor, does not show silencing defects at the main heterochromatic regions. Dhp1 is essential in the sequential steps of establishing silencing in a manner independent of both RNAi and the exosome. Genomic and genetic analysis suggest that Dhp1 is involved in post-transcriptional silencing of repetitive regions through its catalytic activity. Our study is the first investigation into an unexpected role of Dhp1/Rat1/Xrn2 in chromatin-based silencing. These results elucidate how various RNA-processing pathways, acting together or independently, contribute to epigenetic regulation of the eukaryotic genome.
2016-01-28 | GSE77289 | GEO
Project description:Eukaryotic chromatin is organized into either silenced heterochromatin or relaxed euchromatin regions, which controls the accessibility of transcriptional machinery and thus regulates gene expression. In fission yeast, Schizosaccharomyces pombe, Set1 is the sole H3K4 methyltransferase and is mainly enriched at the promoters of actively transcribed genes. In contrast, Clr4 methyltransferase initiates H3K9 methylation, which has long been regarded as a hallmark of heterochromatic silencing. Lsd1 and Lsd2 are two highly conserved H3K4 and H3K9 demethylases. As these histone-modifying enzymes perform critical roles in maintaining histone methylation patterns and, consequently, gene expression profiles, cross-regulations among these enzymes are parts of the complex regulatory networks. Thus, elucidating the mechanisms that govern their signaling and mutual regulations remains crucial. Here, we demonstrated that C-terminal truncation mutants, lsd1-∆HMG and lsd2-∆C, do not compromise the integrity of the Lsd1/2 complex but impair their chromatin-binding capacity at the promoter region of target genomic loci. We identified the protein-protein interactions between Lsd1/2 and Raf2 or Swd2, which are the subunits of the Clr4 complex (CLRC) and Set1-associated complexes (COMPASS), respectively. We showed that Clr4 and Set1 modulate the protein levels of Lsd1 and Lsd2 in opposite ways through the ubiquitin-proteasome-dependent pathway. During heat stress, the protein levels of Lsd1 and Lsd2 are upregulated in a Set1-dependent manner. The increase in protein levels is crucial for differential gene expression under stressed conditions. Together, our results support a cross-regulatory model by which Set1 and Clr4 methyltransferases control the protein levels of Lsd1/2 demethylases to shape the dynamic chromatin landscape.
2023-11-16 | GSE246596 | GEO