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Genetic interactions between error-prone and error-free postreplication repair pathways in Saccharomyces cerevisiae
1Department of Microbiology and Immunology, University of Saskatchewan, Saskatoon, Canada. xiaow@sask.usask.ca
Mutation Research
|October 20, 1999
Summary
The MMS2 gene in yeast plays a crucial role in error-free DNA repair. Mutations in MMS2, when interacting with REV3, suggest two distinct DNA repair pathways, error-free (MMS2) and mutagenic (REV3).
Area of Science:
- Molecular Biology
- Genetics
- Biochemistry
Background:
- The Saccharomyces cerevisiae RAD6 DNA repair group includes error-free postreplication repair (PRR) and mutagenesis pathways.
- The MMS2 gene is essential for error-free PRR; its mutation elevates spontaneous mutation rates.
Purpose of the Study:
- To investigate the mutational spectrum of the mms2 mutator.
- To examine the mutagenic effects and genetic interactions between mms2 and rev3 mutations.
- To elucidate the roles of MMS2 and REV3 in DNA repair pathways.
Main Methods:
- Comparative analysis of mutational spectra between mms2 mutator and wild-type yeast strains.
- Assessment of mutagenic effects and genetic interactions concerning forward mutations, frameshift reversions, and suppressions (amber, ochre).
- Evaluation of synergistic effects of mms2 and rev3 mutations on cell survival following DNA damage.
Main Results:
- The mms2 mutator phenotype is significantly influenced by the functional REV3 gene.
- Synergistic effects of mms2 and rev3 mutations on cell killing by DNA-damaging agents were observed.
- Evidence supports MMS2 and REV3 as components of alternative subpathways within the RAD6 DNA repair pathway.
Conclusions:
- MMS2 and REV3 function in two distinct subpathways of the RAD6 DNA repair pathway.
- These pathways, represented by MMS2 (error-free) and REV3 (mutagenesis), handle similar DNA damage but yield different outcomes.
- MMS2 does not merely suppress REV3 activity; they represent parallel repair mechanisms.