Brc1-dependent recovery from replication stress

Bass, Kirstin L, Murray, Johanne M and O'Connell, Matthew J (2012) Brc1-dependent recovery from replication stress. Journal of Cell Science, 125 (11). pp. 2753-2764. ISSN 0021-9533

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Abstract

BRCT-containing protein 1 (Brc1) is a multi-BRCT (BRCA1 carboxyl terminus) domain protein in Schizosaccharomyces pombe that is required for resistance to chronic replicative stress, but whether this reflects a repair or replication defect is unknown and the subject of this study. We show that brc1Δ cells are significantly delayed in recovery from replication pausing, though this does not activate a DNA damage checkpoint. DNA repair and recombination protein Rad52 is a homologous recombination protein that loads the Rad51 recombinase at resected double-stranded DNA (dsDNA) breaks and is also recruited to stalled replication forks, where it may stabilize structures through its strand annealing activity. Rad52 is required for the viability of brc1Δ cells, and brc1Δ cells accumulate Rad52 foci late in S phase that are potentiated by replication stress. However, these foci contain the single-stranded DNA (ssDNA) binding protein RPA, but not Rad51 or γH2A. Further, these foci are not associated with increased recombination between repeated sequences, or increased post-replication repair. Thus, these Rad52 foci do not represent sites of recombination. Following the initiation of DNA replication, the induction of these foci by replication stress is suppressed by defects in origin recognition complex (ORC) function, which is accompanied by loss of viability and severe mitotic defects. This suggests that cells lacking Brc1 undergo an ORC-dependent rescue of replication stress, presumably through the firing of dormant origins, and this generates RPA-coated ssDNA and recruits Rad52. However, as Rad51 is not recruited, and the checkpoint effector kinase Chk1 is not activated, these structures must not contain the unprotected primer ends found at sites of DNA damage that are required for recombination and checkpoint activation

Item Type: Article
Schools and Departments: School of Life Sciences > Biochemistry
School of Life Sciences > Biology and Environmental Science
School of Life Sciences > Chemistry
School of Life Sciences > Evolution, Behaviour and Environment
School of Life Sciences > Neuroscience
School of Life Sciences > Sussex Centre for Genome Damage and Stability
Subjects: Q Science
R Medicine
Depositing User: Philippa Erasmus
Date Deposited: 11 Jan 2013 14:14
Last Modified: 11 Jan 2013 14:14
URI: http://sro.sussex.ac.uk/id/eprint/43446
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