title: Requirement for XRCC4 and DNA ligase IV in alignment-based gap filling for nonhomologous DNA end joining in vitro.
abstract: In the nonhomologous end joining pathway of DNA double-strand break repair, the ligation step is catalyzed by a complex of XRCC4 and DNA ligase IV. Extracts of CHO-K1 cells are able to accurately rejoin a site-specific free radical-mediated double-strand break with partially complementary overhangs, by a mechanism involving alignment-based gap filling followed by ligation. Extracts of XR-1 cells, which lack XRCC4 and DNA ligase IV, carried out neither gap filling nor ligation. Supplementation of the extracts with recombinant XRCC4/ligase IV, but not with XRCC4 alone, restored gap filling and accurate end joining. The results imply that XRCC4 and ligase IV are essential for alignment-based gap filling, as well as for final ligation of the breaks.
authors.affiliation: Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia 23298, USA.
authors.forename: Jae Wan
authors.initials: JW
authors.lastname: Lee
authors.forename: Steven M
authors.initials: SM
authors.lastname: Yannone
authors.forename: David J
authors.initials: DJ
authors.lastname: Chen
authors.forename: Lawrence F
authors.initials: LF
authors.lastname: Povirk
mesh_terms: D000818:Animals; D001483:Base Sequence; D016466:CHO Cells; D006224:Cricetinae; D000072481:DNA Ligase ATP; D011088:DNA Ligases / Q000378:metabolism*; D004260:DNA Repair; D004268:DNA-Binding Proteins / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism; D016415:Sequence Alignment; D014162:Transfection
chemical_list: D004268:DNA-Binding Proteins; C000607893:LIG4 protein, human; D011994:Recombinant Proteins; C101467:XRCC4 protein, human; D011088:DNA Ligases; D000072481:DNA Ligase ATP