Error-prone repair of stalled replication forks drives mutagenesis and loss of heterozygosity in haploinsufficient BRCA1 cells.
Mol Cell
; 82(20): 3781-3793.e7, 2022 10 20.
Article
em En
| MEDLINE
| ID: mdl-36099913
ABSTRACT
Germline mutations in the BRCA genes are associated with a higher risk of carcinogenesis, which is linked to an increased mutation rate and loss of the second unaffected BRCA allele (loss of heterozygosity, LOH). However, the mechanisms triggering mutagenesis are not clearly understood. The BRCA genes contain high numbers of repetitive DNA sequences. We detected replication forks stalling, DNA breaks, and deletions at these sites in haploinsufficient BRCA cells, thus identifying the BRCA genes as fragile sites. Next, we found that stalled forks are repaired by error-prone pathways, such as microhomology-mediated break-induced replication (MMBIR) in haploinsufficient BRCA1 breast epithelial cells. We detected MMBIR mutations in BRCA1 tumor cells and noticed deletions-insertions (>50 bp) at the BRCA1 genes in BRCA1 patients. Altogether, these results suggest that under stress, error-prone repair of stalled forks is upregulated and induces mutations, including complex genomic rearrangements at the BRCA genes (LOH), in haploinsufficient BRCA1 cells.
Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Proteína BRCA1
/
Replicação do DNA
Limite:
Humans
Idioma:
En
Revista:
Mol Cell
Assunto da revista:
BIOLOGIA MOLECULAR
Ano de publicação:
2022
Tipo de documento:
Article
País de afiliação:
Estados Unidos