title: Promotion of Dnl4-catalyzed DNA end-joining by the Rad50/Mre11/Xrs2 and Hdf1/Hdf2 complexes.
abstract: S. cerevisiae RAD50, MRE11, and XRS2 genes are required for telomere maintenance, cell cycle checkpoint signaling, meiotic recombination, and the efficient repair of DNA double-strand breaks (DSB)s by homologous recombination and nonhomologous end-joining (NHEJ). Here, we demonstrate that the complex formed by Rad50, Mre11, and Xrs2 proteins promotes intermolecular DNA joining by DNA ligase IV (Dnl4) and its associated protein Lif1. Our results show that the Rad50/Mre11/Xrs2 complex juxtaposes linear DNA molecules via their ends to form oligomers and interacts directly with Dnl4/Lif1. We also demonstrate that Rad50/Mre11/Xrs2-mediated intermolecular DNA joining is further stimulated by Hdf1/Hdf2, the yeast homolog of the mammalian Ku70/Ku80 heterodimer. These studies reveal specific functional interplay among the Hdf1/Hdf2, Rad50/Mre11/Xrs2, and Dnl4/Lif1 complexes in NHEJ.
authors.affiliation: Department of Molecular Medicine and Institute of Biotechnology, The University of Texas Health Science Center at San Antonio, 15355 Lambda Drive, San Antonio, TX 78245, USA.
authors.forename: L
authors.initials: L
authors.lastname: Chen
authors.forename: K
authors.initials: K
authors.lastname: Trujillo
authors.forename: W
authors.initials: W
authors.lastname: Ramos
authors.forename: P
authors.initials: P
authors.lastname: Sung
authors.forename: A E
authors.initials: AE
authors.lastname: Tomkinson
mesh_terms: D002384:Catalysis; D000072481:DNA Ligase ATP; D011088:DNA Ligases / Q000302:isolation & purification / Q000378:metabolism*; D004260:DNA Repair; D004271:DNA, Fungal / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism; D004706:Endodeoxyribonucleases / Q000378:metabolism*; D005090:Exodeoxyribonucleases / Q000378:metabolism*; D005656:Fungal Proteins / Q000378:metabolism*; D006801:Humans; D046911:Macromolecular Substances; D018625:Microscopy, Atomic Force; D011995:Recombination, Genetic; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism
chemical_list: D004271:DNA, Fungal; D004268:DNA-Binding Proteins; C000607891:DNL4 protein, S cerevisiae; D005656:Fungal Proteins; C000607893:LIG4 protein, human; D046911:Macromolecular Substances; C086930:RAD50 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; C086929:XRS2 protein, S cerevisiae; C520769:YKU70 protein, S cerevisiae; C520770:YKU80 protein, S cerevisiae; C081647:high affinity DNA-binding factor, S cerevisiae; D004706:Endodeoxyribonucleases; D005090:Exodeoxyribonucleases; C094191:MRE11 protein, S cerevisiae; D011088:DNA Ligases; D000072481:DNA Ligase ATP