Patching and single-strand ligation in nonhomologous DNA end joining despite persistence of a closely opposed 3'-phosphoglycolate-terminated strand break.

ABSTRACT: Previous work showed that in human nuclear extracts, double-strand break substrates bearing partially complementary (-ACG) 3'-phosphoglycolate (PG)-terminated 3' overhangs are joined by a mechanism involving annealing of the terminal CG dinucleotides, PG removal, single-base gap filling and ligation. However, in these extracts only a minority of the breaks are rejoined, and most of the 3'-PG termini remain intact even after several hours. To determine whether the presence of a persistent 3'-PG prevents patching and ligation of the opposite strand, a substrate was constructed with two -ACG overhangs, one PG-terminated and one hydroxyl-terminated. after incubation in HeLa cell nuclear extracts, two major repair products of similar yield were formed: a fully repaired duplex and a nicked duple

SUBMITTER: Zhou RZ 

PROVIDER: S-EPMC2956515 | biostudies-literature | 2010 Sep

REPOSITORIES: biostudies-literature