The mismatch DNA repair heterodimer, hMSH2/6, regulates BLM helicase.

Autor: Qin Yang, Ran Zhang, Xin W. Wang, Linke, Steven P., Sengupta, Sagar, Hickson, Tan D., Pedrazzi, Graziella, Perrera, Claudia, Stagljar, Igor, Littman, Susan J., Modrich, Paul, Harris, Curtis C.
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Zdroj: Oncogene; 5/6/2004, Vol. 23 Issue 21, p3749-3756, 8p
Abstrakt: The human MSH2/6 complex is essential for mismatch recognition during the repair of replication errors. Although mismatch repair components have been implicated in DNA homologous recombination repair, the exact function of hMSH2/6 in this pathway is unclear. Here, we show that the recombinant hMSH2/6 protein complex stimulated the ability of the Bloom's syndrome gene product, BLM, to process Holliday junctions in vitro, an activity that could also be regulated by p53. Consistent with these observations, hMSH6 colocalized with BLM and phospho-ser15-p53 in hydroxyurea-induced RAD51 nuclear foci that may correspond to the sites of presumed stalled DNA replication forks and more likely the resultant DNA double-stranded breaks. In addition, we show that hMSH2 and hMSH6 coimmunoprecipitated with BLM, p53, and RADS1. Both the number of RADS1 foci and the amount of the BLM-p53-RADS1 complex are increased in hMSH2- or hMSH6-deficient cells. These data suggest that hMSH2/6 formed a complex with BLM-p53-RADS 1 in response to the damaged DNA forks during double-stranded break repair. [ABSTRACT FROM AUTHOR]
Databáze: Complementary Index