Schizosaccharomyces pombe
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ABSTRACT:
PROVIDER: PRJNA98201 | ENA |
REPOSITORIES: ENA
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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: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:RNA interference (RNAi) pathways are prevalent throughout the eukaryotic kingdom and well known to regulate gene expression on a post-transcriptional level in the cytoplasm. Less is known about possible functions of RNAi in the nucleus. In the fission yeast Schizosaccharomyces pombe, RNAi is crucial to establish and maintain centromeric heterochromatin and functions to repress genome activity by a chromatin silencing mechanism referred to as co-transcriptional gene silencing (CTGS). Mechanistic details and the physiological relevance of CTGS are unknown. Here we show that RNAi components interact with chromatin at nuclear pores to keep stress response genes in check. We demonstrate that RNAi-mediated CTGS represses stress inducible genes by degrading mRNAs under non-induced conditions. Under chronic heat stress conditions, a Dicer thermoswitch deports Dicer to the cytoplasm, thereby disrupting CTGS and enabling expression of genes implicated in the acquisition of thermotolerance. Taken together, our work highlights a role for nuclear pores and the stress response transcription factor Atf1 in coordinating the interplay between the RNAi machinery and the S. pombe genome and uncovers a novel mode of RNAi regulation in response to an environmental cue.
2012-03-19 | GSE36167 | GEO
Project description:Histone H2A.Z cooperates with RNAi and heterochromatin factors to suppress antisense RNAs
| PRJNA119129 | ENA
Project description:Mediator directs co-transcriptional heterochromatin assembly by RNAi-dependent and -independent pathways.
| PRJNA186678 | ENA
Project description:Rbm10 promotes heterochromatin assembly by interacting with Clr6 and chromatin remodeling complexes
| PRJNA362813 | ENA
Project description:Small interfering RNAs (siRNAs) are known to be involved in both transposon silencing and centromere function, leading us to investigate the interplay between these two roles in the Schizosaccharomyces lineage. In S. pombe, the centromeric repeats produce dicer-dependent siRNAs that are required for maintenance of centromeric structure, function and transcriptional silencing via Argonaute-dependent heterochromatin formation13. However, transposons are silenced in S. pombe by RNAi-independent mechanisms and do not produce abundant siRNAs. To investigate whether centromere-directed siRNA production is conserved within the transposon-rich centromeres of S. japonicus, we isolated and sequenced small RNAs from log-phase S. japonicus cultures. The small RNAs have a modal size of 23 nucleotides and 94% map to transposons, both telomeric and centromeric. Isolation and computational analysis of small RNAs from wild-type S. japonicus
2011-03-09 | E-GEOD-27837 | biostudies-arrayexpress
Project description:Small interfering RNAs (siRNAs) are known to be involved in both transposon silencing and centromere function, leading us to investigate the interplay between these two roles in the Schizosaccharomyces lineage. In S. pombe, the centromeric repeats produce dicer-dependent siRNAs that are required for maintenance of centromeric structure, function and transcriptional silencing via Argonaute-dependent heterochromatin formation13. However, transposons are silenced in S. pombe by RNAi-independent mechanisms and do not produce abundant siRNAs. To investigate whether centromere-directed siRNA production is conserved within the transposon-rich centromeres of S. japonicus, we isolated and sequenced small RNAs from log-phase S. japonicus cultures. The small RNAs have a modal size of 23 nucleotides and 94% map to transposons, both telomeric and centromeric.
2011-03-09 | GSE27837 | GEO
Project description:Nuclear retention of fission yeast dicer is a prerequisite for RNAi-mediated heterochromatin assembly
| PRJNA118241 | ENA