Genetics, Vol. 168, 1855-1865, December 2004, Copyright © 2004
doi:10.1534/genetics.104.032771

Examination of the Roles of Sgs1 and Srs2 Helicases in the Enforcement of Recombination Fidelity in Saccharomyces cerevisiae

Department of Biology, Emory University, Atlanta, Georgia 30322

1 Corresponding author: Department of Biology, Emory University, 1510 Clifton Rd., Atlanta, GA 30322.
E-mail: sue.jinks-robertson{at}emory.edu

Mutation in SGS1, which encodes the yeast homolog of the human Bloom helicase, or in mismatch repair (MMR) genes confers defects in the suppression of mitotic recombination between similar but nonidentical (homeologous) sequences. Mutational analysis of SGS1 suggests that the helicase activity is required for the suppression of both homologous and homeologous recombination and that the C-terminal 200 amino acids may be required specifically for the suppression of homeologous recombination. To clarify the mechanism by which the Sgs1 helicase enforces the fidelity of recombination, we examined the phenotypes associated with SGS1 deletion in MMR-defective and recombination-defective backgrounds. Deletion of SGS1 caused no additional loss of recombination fidelity above that associated with MMR defects, indicating that the suppression of homeologous recombination by Sgs1 may be dependent on MMR. However, the phenotype of the sgs1 rad51 mutant suggests a MMR-independent role of Sgs1 in the suppression of RAD51-independent recombination. While homologous recombination levels increase in sgs1{Delta} and in srs2{Delta} strains, the suppression of homeologous recombination was not relaxed in the srs2 mutant. Thus, although both Sgs1 and Srs2 limit the overall level of mitotic recombination, there are distinct differences in the roles of these helicases with respect to enforcement of recombination fidelity.




This article has been cited by other articles:


Home page
Nucleic Acids ResHome page
M. Kappeler, E. Kranz, K. Woolcock, O. Georgiev, and W. Schaffner
Drosophila bloom helicase maintains genome integrity by inhibiting recombination between divergent DNA sequences
Nucleic Acids Res., December 1, 2008; 36(21): 6907 - 6917.
[Abstract] [Full Text] [PDF]


Home page
GeneticsHome page
A. Deem, K. Barker, K. VanHulle, B. Downing, A. Vayl, and A. Malkova
Defective Break-Induced Replication Leads to Half-Crossovers in Saccharomyces cerevisiae
Genetics, August 1, 2008; 179(4): 1845 - 1860.
[Abstract] [Full Text] [PDF]


Home page
GeneticsHome page
C. Welz-Voegele and S. Jinks-Robertson
Sequence Divergence Impedes Crossover More Than Noncrossover Events During Mitotic Gap Repair in Yeast
Genetics, July 1, 2008; 179(3): 1251 - 1262.
[Abstract] [Full Text] [PDF]


Home page
J. Biol. Chem.Home page
Y. Wu, N. Kantake, T. Sugiyama, and S. C. Kowalczykowski
Rad51 Protein Controls Rad52-mediated DNA Annealing
J. Biol. Chem., May 23, 2008; 283(21): 14883 - 14892.
[Abstract] [Full Text] [PDF]


Home page
GeneticsHome page
J. E. Stone, R. G. Ozbirn, T. D. Petes, and S. Jinks-Robertson
Role of Proliferating Cell Nuclear Antigen Interactions in the Mismatch Repair-Dependent Processing of Mitotic and Meiotic Recombination Intermediates in Yeast
Genetics, March 1, 2008; 178(3): 1221 - 1236.
[Abstract] [Full Text] [PDF]


Home page
Mol. Cell. Biol.Home page
J. A. Smith, L. A. Bannister, V. Bhattacharjee, Y. Wang, B. C. Waldman, and A. S. Waldman
Accurate Homologous Recombination Is a Prominent Double-Strand Break Repair Pathway in Mammalian Chromosomes and Is Modulated by Mismatch Repair Protein Msh2
Mol. Cell. Biol., November 15, 2007; 27(22): 7816 - 7827.
[Abstract] [Full Text] [PDF]


Home page
Mol. Cell. Biol.Home page
S. Flott, C. Alabert, G. W. Toh, R. Toth, N. Sugawara, D. G. Campbell, J. E. Haber, P. Pasero, and J. Rouse
Phosphorylation of Slx4 by Mec1 and Tel1 Regulates the Single-Strand Annealing Mode of DNA Repair in Budding Yeast
Mol. Cell. Biol., September 15, 2007; 27(18): 6433 - 6445.
[Abstract] [Full Text] [PDF]


Home page
Proc. Natl. Acad. Sci. USAHome page
Y. W. Kow, G. Bao, J. W. Reeves, S. Jinks-Robertson, and G. F. Crouse
Oligonucleotide transformation of yeast reveals mismatch repair complexes to be differentially active on DNA replication strands
PNAS, July 3, 2007; 104(27): 11352 - 11357.
[Abstract] [Full Text] [PDF]


Home page
Proc. Natl. Acad. Sci. USAHome page
K. H. Schmidt and R. D. Kolodner
Suppression of spontaneous genome rearrangements in yeast DNA helicase mutants
PNAS, November 28, 2006; 103(48): 18196 - 18201.
[Abstract] [Full Text] [PDF]


Home page
GeneticsHome page
D. Yang, E. B. Goldsmith, Y. Lin, B. C. Waldman, V. Kaza, and A. S. Waldman
Genetic Exchange Between Homeologous Sequences in Mammalian Chromosomes Is Averted by Local Homology Requirements for Initiation and Resolution of Recombination
Genetics, September 1, 2006; 174(1): 135 - 144.
[Abstract] [Full Text] [PDF]


Home page
Mol. Cell. Biol.Home page
K. H. Schmidt, J. Wu, and R. D. Kolodner
Control of Translocations between Highly Diverged Genes by Sgs1, the Saccharomyces cerevisiae Homolog of the Bloom's Syndrome Protein.
Mol. Cell. Biol., July 1, 2006; 26(14): 5406 - 5420.
[Abstract] [Full Text] [PDF]


Home page
Mol. Cell. Biol.Home page
C. D. Putnam, V. Pennaneach, and R. D. Kolodner
Saccharomyces cerevisiae as a Model System To Define the Chromosomal Instability Phenotype
Mol. Cell. Biol., August 15, 2005; 25(16): 7226 - 7238.
[Abstract] [Full Text] [PDF]


Home page
GeneticsHome page
T. Goldfarb and E. Alani
Distinct Roles for the Saccharomyces cerevisiae Mismatch Repair Proteins in Heteroduplex Rejection, Mismatch Repair and Nonhomologous Tail Removal
Genetics, February 1, 2005; 169(2): 563 - 574.
[Abstract] [Full Text] [PDF]