Shelterin and subtelomeric DNA sequences control nucleosome maintenance and genome stability
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ABSTRACT:
PROVIDER: PRJNA497473 | ENA |
REPOSITORIES: ENA
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Project description:Telomeres and the shelterin complex cap and protect the ends of chromosomes. Telomeres are flanked by the subtelomeric sequences that have also been implicated in telomere regulation, although their role is not well defined. Here we show that, in Schizosaccharomyces pombe, the telomere-associated sequences (TAS) present on most subtelomeres are hyper-recombinogenic, have metastable nucleosomes, and unusual low levels of H3K9 methylation. Ccq1, a subunit of shelterin, protects TAS from nucleosome loss by recruiting the heterochromatic repressor complexes CLRC and SHREC, thereby linking nucleosome stability to gene silencing. Nucleosome instability at TAS is independent of telomeric repeats and can be transmitted to an intrachromosomal locus containing an ectopic TAS fragment, indicating that this is an intrinsic property of the underlying DNA sequence. When telomerase recruitment is compromised in cells lacking Ccq1, DNA sequences present in the TAS promote recombination between chromosomal ends, independent of nucleosome abundance, implying an active function of these sequences in telomere maintenance. We propose that Ccq1 and fragile subtelomeres co-evolved to regulate telomere plasticity by controlling nucleosome occupancy and genome stability.
2018-10-19 | GSE121502 | GEO
Project description:Telomeres and the shelterin complex cap and protect the ends of chromosomes. Telomeres are flanked by the subtelomeric sequences that have also been implicated in telomere regulation, although their role is not well defined. Here, we show that, in Schizosaccharomyces pombe, the telomere-associated sequences (TAS) present on most subtelomeres are hyper-recombinogenic, have metastable nucleosomes, and unusual low levels of H3K9 methylation. Ccq1, a subunit of shelterin, protects TAS from nucleosome loss by recruiting the heterochromatic repressor complexes CLRC and SHREC, thereby linking nucleosome stability to gene silencing. Nucleosome instability at TAS is independent of telomeric repeats and can be transmitted to an intrachromosomal locus containing an ectopic TAS fragment, indicating that this is an intrinsic property of the underlying DNA sequence. When telomerase recruitment is compromised in cells lacking Ccq1, DNA sequences present in the TAS promote recombination between chromosomal ends, independent of nucleosome abundance, implying an active function of these sequences in telomere maintenance. We propose that Ccq1 and fragile subtelomeres co-evolved to regulate telomere plasticity by controlling nucleosome occupancy and genome stability.
| S-EPMC6322387 | biostudies-literature
Project description:Efficient replication of terminal sequences is crucial to maintain telomere stability. In fission yeast, the Taz1 protein, the TRF1-2 homolog, plays a prominent role in telomere replication. We and others have shown that the Stn1-Ten1 (ST) complex fulfills important function in telomeres and subtelomeres maintenance, however its function is not fully understood. Here, we analyzed genome-wide replication dynamics using the polymerase usage sequencing (PuSeq) allowing to assess polymerase usage across the genome. We show that the ST complex and Taz1 are crucial for the replication of the STE2-3 subtelomeric region. Both, the ST complex and Taz1, bind specifically to this region and the function of the ST complex relies on its association with the shelterin complex. Strikingly, when the ST complex is compromised, an HR-based fork restart mechanism becomes necessary to ensure replication of the STE2-3 region. Finally, we demonstrate that the firing of an origin, that is controlled by Rif1, within subtelomeric regions circumvents the replication defect of subtelomeres. Overall, we demonstrate that the ST complex is actively recruited at subtelomeres by the shelterin and this ensures replication of the STE2-3 region which exhibits specific features of a hard-to-replicate region.
2022-07-01 | GSE207082 | GEO
Project description:Occupancy profiling of Shelterin components in fission yeast. Facultative heterochromatin regulates gene expression, but its assembly is poorly understood. Previously, we identified facultative heterochromatin islands in the fission yeast genome and found that RNA elimination machinery promotes island assembly at meiotic genes. Here, we report that Taz1, a component of the telomere protection complex Shelterin, is required to assemble heterochromatin islands at regions corresponding to late replication origins that are sites of double-strand break formation during meiosis. The loss of Taz1 and other Shelterin subunits, including Ccq1 that interacts with Clr4/Suv39h, abolishes heterochromatin at late origins and causes defective silencing of associated genes. Moreover, the late origin regulator Rif1 affects heterochromatin at Taz1-dependent islands and subtelomeric regions. We uncover a connection between heterochromatin and replication control, and show that heterochromatin factors affect timing of replication. These analyses implicate Shelterin in facultative heterochromatin assembly at late origins, which has important implications for the maintenance of genome stability and gene regulation. Whole cell extract DNA and DNA recovered from Taz1 or Rif1-immunoprecipitated chromatin of fission yeast were random-prime PCR amplified and labeled with Cy3 (whole cell extract DNA) or with Cy5 (IP DNA) and analyzed using custom 60mer Agilent array that tiles Schizosaccharomyces pombe genome in 300bp intervals alternately on both strands.
2016-06-09 | E-GEOD-78822 | biostudies-arrayexpress
Project description:ChIP-chip analyses of lysine 9 dimethylated histone H3 in Shelterin mutants. Facultative heterochromatin regulates gene expression, but its assembly is poorly understood. Previously, we identified facultative heterochromatin islands in the fission yeast genome and found that RNA elimination machinery promotes island assembly at meiotic genes. Here, we report that Taz1, a component of the telomere protection complex Shelterin, is required to assemble heterochromatin islands at regions corresponding to late replication origins that are sites of double-strand break formation during meiosis. The loss of Taz1 and other Shelterin subunits, including Ccq1 that interacts with Clr4/Suv39h, abolishes heterochromatin at late origins and causes defective silencing of associated genes. Moreover, the late origin regulator Rif1 affects heterochromatin at Taz1-dependent islands and subtelomeric regions. We uncover a connection between heterochromatin and replication control, and show that heterochromatin factors affect timing of replication. These analyses implicate Shelterin in facultative heterochromatin assembly at late origins, which has important implications for the maintenance of genome stability and gene regulation. Whole cell extract DNA and DNA recovered from H3K9 dimethylated chromatin of fission yeast were random-prime PCR amplified and labeled with Cy3 (whole cell extract) or Cy5 (IP DNA) and analyzed using custom 60mer Agilent array that tiles Schizosaccharomyces pombe genome in 300bp intervals alternately on both strands.
2016-06-09 | E-GEOD-78820 | biostudies-arrayexpress
Project description:Occupancy profiling of Shelterin components in fission yeast. Facultative heterochromatin regulates gene expression, but its assembly is poorly understood. Previously, we identified facultative heterochromatin islands in the fission yeast genome and found that RNA elimination machinery promotes island assembly at meiotic genes. Here, we report that Taz1, a component of the telomere protection complex Shelterin, is required to assemble heterochromatin islands at regions corresponding to late replication origins that are sites of double-strand break formation during meiosis. The loss of Taz1 and other Shelterin subunits, including Ccq1 that interacts with Clr4/Suv39h, abolishes heterochromatin at late origins and causes defective silencing of associated genes. Moreover, the late origin regulator Rif1 affects heterochromatin at Taz1-dependent islands and subtelomeric regions. We uncover a connection between heterochromatin and replication control, and show that heterochromatin factors affect timing of replication. These analyses implicate Shelterin in facultative heterochromatin assembly at late origins, which has important implications for the maintenance of genome stability and gene regulation.
2016-06-09 | GSE78822 | GEO
Project description:ChIP-chip analyses of lysine 9 dimethylated histone H3 in Shelterin mutants. Facultative heterochromatin regulates gene expression, but its assembly is poorly understood. Previously, we identified facultative heterochromatin islands in the fission yeast genome and found that RNA elimination machinery promotes island assembly at meiotic genes. Here, we report that Taz1, a component of the telomere protection complex Shelterin, is required to assemble heterochromatin islands at regions corresponding to late replication origins that are sites of double-strand break formation during meiosis. The loss of Taz1 and other Shelterin subunits, including Ccq1 that interacts with Clr4/Suv39h, abolishes heterochromatin at late origins and causes defective silencing of associated genes. Moreover, the late origin regulator Rif1 affects heterochromatin at Taz1-dependent islands and subtelomeric regions. We uncover a connection between heterochromatin and replication control, and show that heterochromatin factors affect timing of replication. These analyses implicate Shelterin in facultative heterochromatin assembly at late origins, which has important implications for the maintenance of genome stability and gene regulation.
2016-06-09 | GSE78820 | GEO
Project description:Occupancy profiling of Rec12 during fission yeast meiosis. Facultative heterochromatin regulates gene expression, but its assembly is poorly understood. Previously, we identified facultative heterochromatin islands in the fission yeast genome and found that RNA elimination machinery promotes island assembly at meiotic genes. Here, we report that Taz1, a component of the telomere protection complex Shelterin, is required to assemble heterochromatin islands at regions corresponding to late replication origins that are sites of double-strand break formation during meiosis. The loss of Taz1 and other Shelterin subunits, including Ccq1 that interacts with Clr4/Suv39h, abolishes heterochromatin at late origins and causes defective silencing of associated genes. Moreover, the late origin regulator Rif1 affects heterochromatin at Taz1-dependent islands and subtelomeric regions. We uncover a connection between heterochromatin and replication control, and show that heterochromatin factors affect timing of replication. These analyses implicate Shelterin in facultative heterochromatin assembly at late origins, which has important implications for the maintenance of genome stability and gene regulation. Whole cell extract DNA and DNA recovered by Rec12 ChIP from fission yeast undergoing synchronous meiosis were random-prime PCR amplified and labeled with Cy3 (whole cell extract) or Cy5 (IP DNA) and analyzed using custom 60mer Agilent array that tiles Schizosaccharomyces pombe genome in 300bp intervals alternately on both strands.
2016-06-09 | E-GEOD-78821 | biostudies-arrayexpress
Project description:Occupancy profiling of Rec12 during fission yeast meiosis. Facultative heterochromatin regulates gene expression, but its assembly is poorly understood. Previously, we identified facultative heterochromatin islands in the fission yeast genome and found that RNA elimination machinery promotes island assembly at meiotic genes. Here, we report that Taz1, a component of the telomere protection complex Shelterin, is required to assemble heterochromatin islands at regions corresponding to late replication origins that are sites of double-strand break formation during meiosis. The loss of Taz1 and other Shelterin subunits, including Ccq1 that interacts with Clr4/Suv39h, abolishes heterochromatin at late origins and causes defective silencing of associated genes. Moreover, the late origin regulator Rif1 affects heterochromatin at Taz1-dependent islands and subtelomeric regions. We uncover a connection between heterochromatin and replication control, and show that heterochromatin factors affect timing of replication. These analyses implicate Shelterin in facultative heterochromatin assembly at late origins, which has important implications for the maintenance of genome stability and gene regulation.
2016-06-09 | GSE78821 | GEO
Project description:BrdU profiling of replication activity in hydroxyurea treated synchronous culture of fission yeast. Facultative heterochromatin regulates gene expression, but its assembly is poorly understood. Previously, we identified facultative heterochromatin islands in the fission yeast genome and found that RNA elimination machinery promotes island assembly at meiotic genes. Here, we report that Taz1, a component of the telomere protection complex Shelterin, is required to assemble heterochromatin islands at regions corresponding to late replication origins that are sites of double-strand break formation during meiosis. The loss of Taz1 and other Shelterin subunits, including Ccq1 that interacts with Clr4/Suv39h, abolishes heterochromatin at late origins and causes defective silencing of associated genes. Moreover, the late origin regulator Rif1 affects heterochromatin at Taz1-dependent islands and subtelomeric regions. We uncover a connection between heterochromatin and replication control, and show that heterochromatin factors affect timing of replication. These analyses implicate Shelterin in facultative heterochromatin assembly at late origins, which has important implications for the maintenance of genome stability and gene regulation.
2016-06-09 | GSE78819 | GEO