Metnase promotes restart and repair of stalled and collapsed replication forks.
Nucleic Acids Res
; 38(17): 5681-91, 2010 Sep.
Article
em En
| MEDLINE
| ID: mdl-20457750
ABSTRACT
Metnase is a human protein with methylase (SET) and nuclease domains that is widely expressed, especially in proliferating tissues. Metnase promotes non-homologous end-joining (NHEJ), and knockdown causes mild hypersensitivity to ionizing radiation. Metnase also promotes plasmid and viral DNA integration, and topoisomerase IIα (TopoIIα)-dependent chromosome decatenation. NHEJ factors have been implicated in the replication stress response, and TopoIIα has been proposed to relax positive supercoils in front of replication forks. Here we show that Metnase promotes cell proliferation, but it does not alter cell cycle distributions, or replication fork progression. However, Metnase knockdown sensitizes cells to replication stress and confers a marked defect in restart of stalled replication forks. Metnase promotes resolution of phosphorylated histone H2AX, a marker of DNA double-strand breaks at collapsed forks, and it co-immunoprecipitates with PCNA and RAD9, a member of the PCNA-like RAD9-HUS1-RAD1 intra-S checkpoint complex. Metnase also promotes TopoIIα-mediated relaxation of positively supercoiled DNA. Metnase is not required for RAD51 focus formation after replication stress, but Metnase knockdown cells show increased RAD51 foci in the presence or absence of replication stress. These results establish Metnase as a key factor that promotes restart of stalled replication forks, and implicate Metnase in the repair of collapsed forks.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Histona-Lisina N-Metiltransferase
/
Reparo do DNA
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Replicação do DNA
Limite:
Humans
Idioma:
En
Revista:
Nucleic Acids Res
Ano de publicação:
2010
Tipo de documento:
Article
País de afiliação:
Estados Unidos