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| Status |
Public on Oct 08, 2018 |
| Title |
Expanding heterochromatin reveals discrete subtelomeric domains delimited by chromatin landscape transitions |
| Organism |
Saccharomyces cerevisiae |
| Experiment type |
Genome binding/occupancy profiling by array
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| Summary |
The eukaryotic genome is divided into chromosomal domains of heterochromatin and euchromatin. Transcriptionally silent heterochromatin is found at subtelomeric regions, leading to the telomeric position effect (TPE) in yeast, fly and man. Heterochromatin generally initiates and spreads from defined loci, and diverse mechanisms prevent the ectopic spread of heterochromatin into euchromatin. Here, we overexpressed the silencing factor Sir3 at various levels in yeast, and found that Sir3 spreading into Extended Silent Domains (ESD) eventually reached saturation at subtelomeres. We observed that Sir3 spreading into ESDs covered zone associated with specific histone marks in wild-type cells and stopped at zones of histone mark transitions including H3K79 tri-methylation levels. The conserved enzyme Dot1 deposits H3K79 methylation, and we found that it is essential for viability upon overexpression of Sir3, but not of a spreading-defective mutant Sir3A2Q. These data suggest that H3K79 methylation actively blocks Sir3 spreading. Lastly, we demonstrate that our work uncovers previously uncharacterized discrete subtelomeric domains associated with specific chromatin features, that offers a new viewpoint on how to separate subtelomeres from the core chromosome.
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| Overall design |
Comparison of Sir3 spreading on chromatin in different strains : WT (yAT191, in duplicates), different levels of SIR3 ovexpression (pADH,pTEF and pGPD) with duplicates and different strain background for the pGPD-SIR3 strains. We also studied the influence of Sir2 on Sir3 spreading by studying Sir3 spreading in strains overexpressing SIR2(yAT1667) and co-overexpressing Sir2 and Sir3. Strains overexpressing the SIR3-A2Q point mutant were used to study the influence of telomere clustering on the genome (yAT1256). Lastly Sir3 binding in strains overexpressing SIR3 or in dot1 mutant strains overexpressing SIR3 was studied on release from a 5mM NAM YPD medium to a fresh YPD medium ( 8hours of growth).
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| Contributor(s) |
Hocher A |
| Citation(s) |
30355601 |
| Submission date |
Nov 03, 2017 |
| Last update date |
Jan 14, 2019 |
| Contact name |
Angela Taddei |
| E-mail(s) |
angela.taddei@curie.fr
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| Phone |
+33 (0)1 56 24 67 04
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| Organization name |
Institut Curie
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| Street address |
26 rue d'Ulm
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| City |
Paris |
| ZIP/Postal code |
75005 |
| Country |
France |
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| Platforms (1) |
| GPL4131 |
Agilent-014810 Yeast Whole Genome ChIP-on-Chip Microarray 4x44K (G4493A) |
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| Samples (19)
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| Relations |
| BioProject |
PRJNA417053 |
| Supplementary file |
Size |
Download |
File type/resource |
| GSE106499_RAW.tar |
141.1 Mb |
(http)(custom) |
TAR (of GPR, TXT) |
| Processed data included within Sample table |
| Processed data provided as supplementary file |
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