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Brc1-dependent recovery from replication stress

journal contribution
posted on 2023-06-08, 14:12 authored by Kirstin L Bass, Jo Murray, Matthew J O'Connell
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 brc1? 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 brc1? cells, and brc1? 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 ?H2A. 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

History

Publication status

  • Published

Journal

Journal of Cell Science

ISSN

0021-9533

Publisher

Company of Biologists

Issue

11

Volume

125

Page range

2753-2764

Department affiliated with

  • Biochemistry Publications

Full text available

  • No

Peer reviewed?

  • Yes

Legacy Posted Date

2013-01-11

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