Translesion DNA synthesis-assisted non-homologous end-joining of complex double-strand breaks prevents loss of DNA sequences in mammalian cells.

ABSTRACT: Double strand breaks (DSB) are severe DNA lesions, and if not properly repaired, may lead to cell death or cancer. While there is considerable data on the repair of simple DSB (sDSB) by non-homologous end-joining (NHEJ), little is known about the repair of complex DSBs (cDSB), namely breaks with a nearby modification, which precludes ligation without prior processing. To study the mechanism of cDSB repair we developed a plasmid-based shuttle assay for the repair of a defined site-specific cDSB in cultured mammalian cells. Using this assay we found that repair efficiency and accuracy of a cDSB with an abasic site in a 5' overhang was reduced compared with a sDSB. Translesion DNA synthesis (TLS) across the abasic site located at the break prevented loss of DNA sequences, but was highly mutag

SUBMITTER: Covo S 

PROVIDER: S-EPMC2777433 | biostudies-literature | 2009 Nov

REPOSITORIES: biostudies-literature