title: Xrs2 Dependent and Independent Functions of the Mre11-Rad50 Complex.
abstract: The Mre11-Rad50-Xrs2/Nbs1 (MRX/N) complex orchestrates the cellular response to DSBs through its structural, enzymatic, and signaling roles. Xrs2/Nbs1 is essential for nuclear translocation of Mre11, but its role as a component of the complex is not well defined. Here, we demonstrate that nuclear localization of Mre11 (Mre11-NLS) is able to bypass several functions of Xrs2, including DNA end resection, meiosis, hairpin resolution, and cellular resistance to clastogens. Using purified components, we show that the MR complex has equivalent activity to MRX in cleavage of protein-blocked DNA ends. Although Xrs2 physically interacts with Sae2, we found that end resection in its absence remains Sae2 dependent in vivo and in vitro. MRE11-NLS was unable to rescue the xrs2Δ defects in Tel1/ATM kinase signaling and non-homologous end joining, consistent with the role of Xrs2 as a chaperone and adaptor protein coordinating interactions between the MR complex and other repair proteins.
authors.affiliation: Department of Biological Sciences, Columbia University, New York, NY 10027, USA; Department of Microbiology & Immunology, Columbia University Medical Center, New York, NY 10032, USA.
authors.forename: Julyun
authors.initials: J
authors.lastname: Oh
authors.affiliation: Department of Biological Sciences, Columbia University, New York, NY 10027, USA; Department of Microbiology & Immunology, Columbia University Medical Center, New York, NY 10032, USA.
authors.forename: Amr
authors.initials: A
authors.lastname: Al-Zain
authors.affiliation: Institute of Molecular Cancer Research, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland.
authors.forename: Elda
authors.initials: E
authors.lastname: Cannavo
authors.affiliation: Institute of Molecular Cancer Research, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland.
authors.forename: Petr
authors.initials: P
authors.lastname: Cejka
authors.affiliation: Department of Microbiology & Immunology, Columbia University Medical Center, New York, NY 10032, USA. Electronic address: lss5@cumc.columbia.edu.
authors.forename: Lorraine S
authors.initials: LS
authors.lastname: Symington
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000235:genetics / Q000378:metabolism; D001665:Binding Sites; D002166:Camptothecin / Q000494:pharmacology; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism; D002868:Chromosomal Proteins, Non-Histone / Q000235:genetics / Q000378:metabolism; D053903:DNA Breaks, Double-Stranded / Q000187:drug effects; D059766:DNA End-Joining Repair; D004271:DNA, Fungal / Q000235:genetics* / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D004706:Endodeoxyribonucleases / Q000235:genetics* / Q000378:metabolism; D004720:Endonucleases / Q000172:deficiency / Q000235:genetics; D005090:Exodeoxyribonucleases / Q000235:genetics* / Q000378:metabolism; D015966:Gene Expression Regulation, Fungal; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism; D008741:Methyl Methanesulfonate / Q000494:pharmacology; D011485:Protein Binding; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism; D021381:Protein Transport; D012441:Saccharomyces cerevisiae / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics* / Q000378:metabolism; D015398:Signal Transduction
chemical_list: C091561:ATM1 protein, S cerevisiae; D018528:ATP-Binding Cassette Transporters; D002868:Chromosomal Proteins, Non-Histone; D004271:DNA, Fungal; D004268:DNA-Binding Proteins; D047908:Intracellular Signaling Peptides and Proteins; C086930:RAD50 protein, S cerevisiae; C107849:SAE2 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; C086929:XRS2 protein, S cerevisiae; D008741:Methyl Methanesulfonate; D017346:Protein Serine-Threonine Kinases; C513623:TEL1 protein, S cerevisiae; D004706:Endodeoxyribonucleases; D004720:Endonucleases; D005090:Exodeoxyribonucleases; C094191:MRE11 protein, S cerevisiae; D002166:Camptothecin
keywords: DNA repair; Mre11; Rad50; Sae2; Xrs2; end resection; homologous recombination