DNA double-strand break repair pathway choice is directed by distinct MRE11 nuclease activities.
Mol Cell
; 53(1): 7-18, 2014 Jan 09.
Article
em En
| MEDLINE
| ID: mdl-24316220
ABSTRACT
MRE11 within the MRE11-RAD50-NBS1 (MRN) complex acts in DNA double-strand break repair (DSBR), detection, and signaling; yet, how its endo- and exonuclease activities regulate DSBR by nonhomologous end-joining (NHEJ) versus homologous recombination (HR) remains enigmatic. Here, we employed structure-based design with a focused chemical library to discover specific MRE11 endo- or exonuclease inhibitors. With these inhibitors, we examined repair pathway choice at DSBs generated in G2 following radiation exposure. While nuclease inhibition impairs radiation-induced replication protein A (RPA) chromatin binding, suggesting diminished resection, the inhibitors surprisingly direct different repair outcomes. Endonuclease inhibition promotes NHEJ in lieu of HR, while exonuclease inhibition confers a repair defect. Collectively, the results describe nuclease-specific MRE11 inhibitors, define distinct nuclease roles in DSB repair, and support a mechanism whereby MRE11 endonuclease initiates resection, thereby licensing HR followed by MRE11 exonuclease and EXO1/BLM bidirectional resection toward and away from the DNA end, which commits to HR.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Fase G2
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Proteínas de Ligação a DNA
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Inibidores Enzimáticos
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Quebras de DNA de Cadeia Dupla
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Reparo do DNA por Junção de Extremidades
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Reparo de DNA por Recombinação
Limite:
Humans
Idioma:
En
Revista:
Mol Cell
Assunto da revista:
BIOLOGIA MOLECULAR
Ano de publicação:
2014
Tipo de documento:
Article
País de afiliação:
Japão