Pombe_44k_ChIP-on-chip
Ontology highlight
ABSTRACT:
ORGANISM(S): Schizosaccharomyces pombe
PROVIDER: GSE3186 | GEO | 2005/08/31
SECONDARY ACCESSION(S): PRJNA92837
REPOSITORIES: GEO
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Project description:ChIP-on-chip analyses of JmjC protein Epe1 in fission yeast. Keywords: ChIP-on_chip
2006-06-09 | GSE4878 | GEO
Project description:One key aspect of epigenetic inheritance is that chromatin structure can be stably inherited through generations even after removal of the signal that establishes such structure. In fission yeast, the RNA interference (RNAi) machinery is critical for initial targeting of histone methyltransferase Clr4 to pericentric repeats to establish heterochromatin. However, pericentric heterochromatin cannot be properly inherited in the absence of RNAi, suggesting the existence of mechanisms that counteract chromatin structure inheritance. Here we show that in the absence of certain components of the INO80 chromatin-remodeling complex, pericentric heterochromatin can be properly inherited in RNAi mutants. The ability of INO80 to counter heterochromatin inheritance is attributed to one accessory subunit Iec5, which promotes histone turnover at heterochromatin regions, but has little effects on nucleosome positioning at heterochromatin, gene expression, or the DNA damage response. Slow histone turnover preserves parental histones at repeat regions to enhance epigenetic inheritance of heterochromatin not only in RNAi mutants but also in wild type cells. Our analyses demonstrate the importance of INO80 in controlling heterochromatin inheritance and maintaining the proper heterochromatin landscape of the genome.
2020-11-18 | GSE150542 | GEO
Project description:RNAi is a conserved mechanism in which small interfering RNAs (siRNAs) guide the degradation of cognate RNAs, but also promote heterochromatin assembly at repetitive DNA elements such as centromeric repeats. However, the full extent of RNAi functions and its endogenous targets have not been explored. Here we show that in the fission yeast Schizosaccharomyces pombe, RNAi and heterochromatin factors cooperate to silence diverse loci, including sexual differentiation genes, genes encoding transmembrane proteins, and retrotransposons that are also targeted by the exosome RNA degradation machinery. In the absence of the exosome, transcripts are processed preferentially by the RNAi machinery, revealing widespread occurrence of siRNA clusters and corresponding increase in heterochromatin modifications across large domains. We show that the generation of siRNAs and heterochromatin assembly by RNAi is triggered by a mechanism involving the canonical poly(A) polymerase Pla1 and an associated RNA surveillance factor Red1, which also activate the exosome. Remarkably, siRNA production and heterochromatin modifications at genes are regulated by environmental growth conditions, and by developmental signals that induce gene expression during sexual differentiation. Our analyses uncover interplay between RNAi and the exosome that is conserved in higher eukaryotes, and show that differentiation signals modulate RNAi silencing to regulate developmental genes. 8 ChIP samples
2012-11-26 | E-GEOD-41642 | biostudies-arrayexpress
Project description:At Schizosaccharomyces pombe centromeres, heterochromatin formation is required for de novo incorporation of the histone H3 variant CENP-A/Cnp1, which in turn directs kinetochore assembly and ultimately chromosome segregation during mitosis. Noncoding RNAs (ncRNAs) transcribed by RNA polymerase II (Pol II) directs heterochromatin formation via the RNAi machinery, but also through RNAiindependent RNA processing factors. Control of centromeric ncRNA transcription is therefore a key factor for proper centromere function. We here use transcriptional profiling, gene inactivation experiments, and chromatin immunoprecipitation analyses to demonstrate that the Mediator complex directs ncRNA transcription and regulates centromeric heterochromatin formation in fission yeast. Mediator co-localizes with Pol II at centromeres and loss of the Mediator subunit Med20 causes a dramatic increase in pericentromeric transcription and desilencing of the core centromere. As a consequence, heterochromatin formation is impaired both via the RNAi dependent and independent pathways, resulting in loss of CENP-A/Cnp1 from the core centromere, defect kinetochore function, and a severe chromosome segregation defect. Interestingly, the increased centromeric transcription observed in med20Δ appears to directly block CENP-A/Cnp1 incorporation and inhibition of Pol II transcription can suppress the observed phenotypes. Our data thus identify Mediator as a crucial regulator of ncRNA transcription at fission yeast centromeres and add another crucial layer of regulation to centromere function. 3 samples examined: wild type chromatin incubated with beads as the non antibody control, wild type chromatin incubated with RNA Polymerase II CTD domain antibody and Protein G beads, and TAP-Med7 cells chromatin incubated with IgG beads.
2012-11-06 | E-GEOD-35524 | biostudies-arrayexpress
Project description:RNAi is a conserved mechanism in which small interfering RNAs (siRNAs) guide the degradation of cognate RNAs, but also promote heterochromatin assembly at repetitive DNA elements such as centromeric repeats. However, the full extent of RNAi functions and its endogenous targets have not been explored. Here we show that in the fission yeast Schizosaccharomyces pombe, RNAi and heterochromatin factors cooperate to silence diverse loci, including sexual differentiation genes, genes encoding transmembrane proteins, and retrotransposons that are also targeted by the exosome RNA degradation machinery. In the absence of the exosome, transcripts are processed preferentially by the RNAi machinery, revealing widespread occurrence of siRNA clusters and corresponding increase in heterochromatin modifications across large domains. We show that the generation of siRNAs and heterochromatin assembly by RNAi is triggered by a mechanism involving the canonical poly(A) polymerase Pla1 and an associated RNA surveillance factor Red1, which also activate the exosome. Remarkably, siRNA production and heterochromatin modifications at genes are regulated by environmental growth conditions, and by developmental signals that induce gene expression during sexual differentiation. Our analyses uncover interplay between RNAi and the exosome that is conserved in higher eukaryotes, and show that differentiation signals modulate RNAi silencing to regulate developmental genes.
2012-11-26 | GSE41642 | GEO
Project description:At Schizosaccharomyces pombe centromeres, heterochromatin formation is required for de novo incorporation of the histone H3 variant CENP-A/Cnp1, which in turn directs kinetochore assembly and ultimately chromosome segregation during mitosis. Noncoding RNAs (ncRNAs) transcribed by RNA polymerase II (Pol II) directs heterochromatin formation via the RNAi machinery, but also through RNAiindependent RNA processing factors. Control of centromeric ncRNA transcription is therefore a key factor for proper centromere function. We here use transcriptional profiling, gene inactivation experiments, and chromatin immunoprecipitation analyses to demonstrate that the Mediator complex directs ncRNA transcription and regulates centromeric heterochromatin formation in fission yeast. Mediator co-localizes with Pol II at centromeres and loss of the Mediator subunit Med20 causes a dramatic increase in pericentromeric transcription and desilencing of the core centromere. As a consequence, heterochromatin formation is impaired both via the RNAi dependent and independent pathways, resulting in loss of CENP-A/Cnp1 from the core centromere, defect kinetochore function, and a severe chromosome segregation defect. Interestingly, the increased centromeric transcription observed in med20Δ appears to directly block CENP-A/Cnp1 incorporation and inhibition of Pol II transcription can suppress the observed phenotypes. Our data thus identify Mediator as a crucial regulator of ncRNA transcription at fission yeast centromeres and add another crucial layer of regulation to centromere function.
2012-11-06 | GSE35524 | GEO
Project description:We have performed a genome wide investigation for the binding locations of the transcriptional co-repressor proteins Ssn6, Tup11 and Tup12 in the fission yeast Schizosaccharomyces pombe. We have used a ChIP protocol described previously (Robyr et al, 2003) with microarrays containing ORF and IGR fragments representing the complete fission yeast genome (Wiren et al, 2005). Keywords: ChIP-CHIP
2006-11-15 | GSE4506 | GEO
Project description:We have performed a genome wide investigation for the binding locations of the transcriptional co-repressor proteins Ssn6, Tup11 and Tup12 in the fission yeast Schizosaccharomyces pombe. We have used a ChIP protocol described previously (Robyr et al, 2003) with microarrays containing ORF and IGR fragments representing the complete fission yeast genome (Wiren et al, 2005). Keywords: ChIP-CHIP
2006-11-15 | GSE4505 | GEO
Project description:We have performed a genome wide investigation for the binding locations of the transcriptional co-repressor proteins Ssn6, Tup11 and Tup12 in the fission yeast Schizosaccharomyces pombe. We have used a ChIP protocol described previously (Robyr et al, 2003) with microarrays containing ORF and IGR fragments representing the complete fission yeast genome (Wiren et al, 2005). Keywords: ChIP-CHIP
2006-11-15 | GSE4503 | GEO
Project description:Constitutive domains of repressive heterochromatin are maintained within the fission yeast genome through self-reinforcing mechanisms involving histone methylation and small RNAs. Non-coding RNAs generated from heterochromatic regions are processed into small RNAs by the RNA interference pathway, and are subject to silencing through both transcriptional and post-transcriptional mechanisms. While the pathways involved in maintenance of the repressive heterochromatin state are reasonably well understood, less is known about the requirements for its establishment. Here we describe a novel role for the post-transcriptional regulatory factor Mkt1 in establishment of heterochromatin at pericentromeres in fission yeast. Loss of Mkt1 does not affect maintenance of existing heterochromatin, but does affect its recovery following depletion, as well as de novo establishment of heterochromatin on a mini-chromosome. Pathway dissection revealed that Mkt1 is required for RNAi-mediated post-transcriptional silencing, downstream of small RNA production. Mkt1 physically associates with pericentromeric transcripts, and is additionally required for maintenance of silencing and heterochromatin at centromeres when transcriptional silencing is impaired. Our findings provide new insight into the mechanism of RNAi-mediated post-transcriptional silencing in fission yeast, and unveil an important role for post-transcriptional silencing in establishment of heterochromatin that is dispensable when full transcriptional silencing is imposed.
2019-11-28 | PXD015484 | Pride