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A SIR-independent role for cohesin in subtelomeric silencing and organization

Kothiwal, Deepash and Laloraya, Shikha (2019) A SIR-independent role for cohesin in subtelomeric silencing and organization. In: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 116 (12). pp. 5659-5664.

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Official URL: https://dx.doi.org/10.1073/pnas.1816582116

Abstract

Cohesin is a key determinant of chromosome architecture due to its DNA binding and tethering ability. Cohesin binds near centromeres and chromosome arms and also close to telomeres, but its role near telomeres remains elusive. In budding yeast, transcription within 20 kb of telomeres is repressed, in part by the histone-modifying silent information regulator (SIR) complex. However, extensive subtelomeric repressed domains lie outside the SIR-binding region, but the mechanism of silencing in these regions remains poorly understood. Here, we report a role for cohesin in subtelomeric silencing that extends even beyond the zone of SIR binding. Clusters of subtelomeric genes were preferentially derepressed in a cohesin mutant, whereas SIR binding was unaltered. Genetic interactions with known telomere silencing factors indicate that cohesin operates independent of the SIR-mediated pathway for telomeric silencing. Mutant cells exhibited Mpk1-dependent Sir3 hyperphosphorylation that contributes to subtelomeric derepression to a limited extent. Compaction of subtelomeric domains and tethering to the nuclear envelope were impaired in mutant cells. Our findings provide evidence for a unique SIR-independent mechanism of subtelomeric repression mediated by cohesin.

Item Type: Journal Article
Additional Information: The copyright for this article belongs to NATL ACAD SCIENCES.
Keywords: cohesin; silencing; telomere; chromatin organization; transcriptome
Department/Centre: Division of Biological Sciences > Biochemistry
Depositing User: Id for Latest eprints
Date Deposited: 24 Apr 2019 05:39
Last Modified: 24 Apr 2019 05:39
URI: http://eprints.iisc.ac.in/id/eprint/62368

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