eprintid: 1370644
rev_number: 37
eprint_status: archive
userid: 608
dir: disk0/01/37/06/44
datestamp: 2013-03-08 16:00:20
lastmod: 2019-10-19 08:41:04
status_changed: 2013-03-08 16:00:20
type: thesis
metadata_visibility: show
item_issues_count: 0
creators_name: Borges, VSF
title: Establishment of sister chromatid cohesion during DNA replication in Saccharomyces cerevisiae
ispublished: unpub
divisions: A01
divisions: B02
divisions: C08
keywords: chromosome segregation, sister chromatid cohesion, cohesin, Smc3 acetylation/deacetylation, Hos1, Ctf4, Chl1
abstract: Establishment of sister chromatid cohesion is a process thought to occur as the replication fork passes chromosomal loci bound by the cohesin complex. After fork passage, cohesin holds together pairs of replication products to allow their recognition by the mitotic machinery for segregation into daughter cells. In budding yeast, cohesin is loaded onto chromosomes during the G1 phase of the cell cycle. During S phase, the replication fork-associated acetyltransferase Eco1 acetylates the cohesin subunit Smc3 to promote the establishment of sister chromatid cohesion. At the time of anaphase, Smc3 loses its acetylation again, but the Smc3 deacetylase and the possible importance of Smc3 deacetylation were unknown. I show that the class I histone deacetylase family member Hos1 is responsible for Smc3 deacetylation. Cohesin is protected from deacetylation while bound to chromosomes but is deacetylated as soon as it dissociates from chromosomes at anaphase onset. Nonacetylated Smc3 is required as a substrate for cohesion establishment in the following cell cycle. Smc3 acetylation during DNA replication renders cohesin resistant against the cohesin destabiliser Wapl. However, because in the absence of Wapl cohesin acetylation is dispensable for cohesion establishment, I have turned my attention to additional ‘cohesion establishment factors’ replication fork-associated proteins required for efficient cohesion establishment. These include Chl1, Ctf4, Ctf18, Mrc1, Tof1 and Csm3. I have used genetic and molecular assays to investigate the relationship of these cohesion establishment factors with the cohesin acetylation pathway. This revealed a contribution of all of these factors to efficient cohesin acetylation. However, removal of the cohesin destabiliser Wapl corrected the cohesion defect in all of the cohesion establishment mutants, except Ctf4 and Chl1. Furthermore, my genetic analysis revealed pronounced synthetic interactions of these two factors with Eco1. Ctf4 and Chl1 therefore define a subset of Eco1-independent cohesion establishment factors, whose possible mechanism of action I have started to investigate.
date: 2012-11-28
vfaculties: VFLS
oa_status: green
thesis_class: doctoral_open
language: eng
thesis_view: UCL_Thesis
dart: DART-Europe
primo: open
primo_central: open_green
verified: verified_manual
elements_source: Manually entered
elements_id: 834080
lyricists_name: Borges, Vanessa De
lyricists_id: VDSBO81
full_text_status: public
pagerange: ? - ?
pages: 138
institution: UCL (University College London)
department: Faculty of Life Sciences
thesis_type: Doctoral
editors_name: Uhlmann, F
citation:        Borges, VSF;      (2012)    Establishment of sister chromatid cohesion during DNA replication in Saccharomyces cerevisiae.                   Doctoral thesis , UCL (University College London).     Green open access   
 
document_url: https://discovery-pp.ucl.ac.uk/id/eprint/1370644/1/VB_thesis_final.pdf