Repair of Endonuclease-Induced Double-Strand Breaks in Saccharomyces cerevisiae: Essential Role for Genes Associated with Nonhomologous End-Joining

Corresponding author: Michael A. Resnick, Laboratory of Molecular Genetics, National Institute of Environmental Health Sciences, 111 Alexander Dr., Research Triangle Park, NC 27709., resnick{at}niehs.nih.gov (E-mail)

Communicating editor: L. S. SYMINGTON

Repair of double-strand breaks (DSBs) in chromosomal DNA by nonhomologous end-joining (NHEJ) is not well characterized in the yeast Saccharomyces cerevisiae. Here we demonstrate that several genes associated with NHEJ perform essential functions in the repair of endonuclease-induced DSBs in vivo. Galactose-induced expression of EcoRI endonuclease in rad50, mre11, or xrs2 mutants, which are deficient in plasmid DSB end-joining and some forms of recombination, resulted in G2 arrest and rapid cell killing. Endonuclease synthesis also produced moderate cell killing in sir4 strains. In contrast, EcoRI caused prolonged cell-cycle arrest of recombination-defective rad51, rad52, rad54, rad55, and rad57 mutants, but cells remained viable. Cell-cycle progression was inhibited in excision repair-defective rad1 mutants, but not in rad2 cells, indicating a role for Rad1 processing of the DSB ends. Phenotypic responses of additional mutants, including exo1, srs2, rad5, and rdh54 strains, suggest roles in recombinational repair, but not in NHEJ. Interestingly, the rapid cell killing in haploid rad50 and mre11 strains was largely eliminated in diploids, suggesting that the cohesive-ended DSBs could be efficiently repaired by homologous recombination throughout the cell cycle in the diploid mutants. These results demonstrate essential but separable roles for NHEJ pathway genes in the repair of chromosomal DSBs that are structurally similar to those occurring during cellular development.

This article has been cited by other articles:

				M. Malik, K. C. Nitiss, V. Enriquez-Rios, and J. L. Nitiss Roles of nonhomologous end-joining pathways in surviving topoisomerase II-mediated DNA damage. Mol. Cancer Ther., June 1, 2006; 5(6): 1405 - 1414. [Abstract] [Full Text] [PDF]

				S. Chen, A. A. Davies, D. Sagan, and H. D. Ulrich The RING finger ATPase Rad5p of Saccharomyces cerevisiae contributes to DNA double-strand break repair in a ubiquitin-independent manner Nucleic Acids Res., October 13, 2005; 33(18): 5878 - 5886. [Abstract] [Full Text] [PDF]

				L. K. Lewis, G. Karthikeyan, J. Cassiano, and M. A. Resnick Reduction of nucleosome assembly during new DNA synthesis impairs both major pathways of double-strand break repair Nucleic Acids Res., September 1, 2005; 33(15): 4928 - 4939. [Abstract] [Full Text] [PDF]

				S. E. Liberti and L. J. Rasmussen Is hEXO1 a Cancer Predisposing Gene? Mol. Cancer Res., August 1, 2004; 2(8): 427 - 432. [Full Text] [PDF]

				J.-L. Ma, E. M. Kim, J. E. Haber, and S. E. Lee Yeast Mre11 and Rad1 Proteins Define a Ku-Independent Mechanism To Repair Double-Strand Breaks Lacking Overlapping End Sequences Mol. Cell. Biol., December 1, 2003; 23(23): 8820 - 8828. [Abstract] [Full Text] [PDF]

				M. van den Bosch, J. B. M. Zonneveld, K. Vreeken, F. A. T. de Vries, P. H. M. Lohman, and A. Pastink Differential expression and requirements for Schizosaccharomyces pombeRAD52 homologs in DNA repair and recombination Nucleic Acids Res., March 15, 2002; 30(6): 1316 - 1324. [Abstract] [Full Text] [PDF]

				L. K. Lewis, G. Karthikeyan, J. W. Westmoreland, and M. A. Resnick Differential Suppression of DNA Repair Deficiencies of Yeast rad50, mre11 and xrs2 Mutants by EXO1 and TLC1 (the RNA Component of Telomerase) Genetics, January 1, 2002; 160(1): 49 - 62. [Abstract] [Full Text] [PDF]

				G. M. Chin and A. M. Villeneuve C. elegans mre-11 is required for meiotic recombination and DNA repair but is dispensable for the meiotic G2 DNA damage checkpoint Genes & Dev., March 1, 2001; 15(5): 522 - 534. [Abstract] [Full Text]

				J. A. Clikeman, G. J. Khalsa, S. L. Barton, and J. A. Nickoloff Homologous Recombinational Repair of Double-Strand Breaks in Yeast Is Enhanced by MAT Heterozygosity Through yKU-Dependent and -Independent Mechanisms Genetics, February 1, 2001; 157(2): 579 - 589. [Abstract] [Full Text]

				R. G. Sargent, J. L. Meservy, B. D. Perkins, A. E. Kilburn, Z. Intody, G. M. Adair, R. S. Nairn, and J. H. Wilson Role of the nucleotide excision repair gene ERCC1 in formation of recombination-dependent rearrangements in mammalian cells Nucleic Acids Res., October 1, 2000; 28(19): 3771 - 3778. [Abstract] [Full Text] [PDF]

				D. Gebow, N. Miselis, and H. L. Liber Homologous and Nonhomologous Recombination Resulting in Deletion: Effects of p53 Status, Microhomology, and Repetitive DNA Length and Orientation Mol. Cell. Biol., June 1, 2000; 20(11): 4028 - 4035. [Abstract] [Full Text]

				C. W. Moore, J. McKoy, M. Dardalhon, D. Davermann, M. Martinez, and D. Averbeck DNA Damage-Inducible and RAD52-Independent Repair of DNA Double-Strand Breaks in Saccharomyces cerevisiae Genetics, March 1, 2000; 154(3): 1085 - 1099. [Abstract] [Full Text]

				T. T. Paull and M. Gellert A mechanistic basis for Mre11-directed DNA joining at microhomologies PNAS, June 6, 2000; 97(12): 6409 - 6414. [Abstract] [Full Text] [PDF]