Schizosaccharomyces pombe
Ontology highlight
ABSTRACT:
OTHER RELATED OMICS DATASETS IN: GSE30837
PROVIDER: PRJNA154563 | ENA |
REPOSITORIES: ENA
Dataset's files
| Action | DRS | |||
|---|---|---|---|---|
| SRR315117.fastq.gz | Fastqsanger.gz | |||
| SRR315118.fastq.gz | Fastqsanger.gz |
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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.
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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.
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