Smarcal1 promotes double-strand-break repair by nonhomologous end-joining.
Nucleic Acids Res
; 43(13): 6359-72, 2015 Jul 27.
Article
em En
| MEDLINE
| ID: mdl-26089390
ABSTRACT
Smarcal1 is a SWI/SNF-family protein with an ATPase domain involved in DNA-annealing activities and a binding site for the RPA single-strand-DNA-binding protein. Although the role played by Smarcal1 in the maintenance of replication forks has been established, it remains unknown whether Smarcal1 contributes to genomic DNA maintenance outside of the S phase. We disrupted the SMARCAL1 gene in both the chicken DT40 and the human TK6 B cell lines. The resulting SMARCAL1(-/-) clones exhibited sensitivity to chemotherapeutic topoisomerase 2 inhibitors, just as nonhomologous end-joining (NHEJ) null-deficient cells do. SMARCAL1(-/-) cells also exhibited an increase in radiosensitivity in the G1 phase. Moreover, the loss of Smarcal1 in NHEJ null-deficient cells does not further increase their radiosensitivity. These results demonstrate that Smarcal1 is required for efficient NHEJ-mediated DSB repair. Both inactivation of the ATPase domain and deletion of the RPA-binding site cause the same phenotype as does null-mutation of Smarcal1, suggesting that Smarcal1 enhances NHEJ, presumably by interacting with RPA at unwound single-strand sequences and then facilitating annealing at DSB ends. SMARCAL1(-/-)cells showed a poor accumulation of Ku70/DNA-PKcs and XRCC4 at DNA-damage sites. We propose that Smarcal1 maintains the duplex status of DSBs to ensure proper recruitment of NHEJ factors to DSB sites.
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Bases de dados:
MEDLINE
Assunto principal:
DNA Helicases
/
Quebras de DNA de Cadeia Dupla
/
Reparo do DNA por Junção de Extremidades
Limite:
Animals
/
Humans
Idioma:
En
Revista:
Nucleic Acids Res
Ano de publicação:
2015
Tipo de documento:
Article
País de afiliação:
Japão