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Updated: Aug 3, 2026
Genetic Studies of Human DNA Repair Proteins Using Yeast as a Model System
Published on: March 18, 2010
Isolation and characterization of MMS-sensitive mutants of Saccharomyces cerevisiae
Abstract:
We have isolated mutants sensitive to methyl methanesulfonate (MMS) in Saccharomyces cerevisiae. Alleles of rad1, rad4, rad52, rad55 and rad57 were found amoung these mms mutants. Twenty-nine of the mms mutants which complement the existing radiation-sensitive (rad and rev) mutants belong to 22 new complementation groups. Mutants from five complementation groups are sensitive only to MMS. Mutants of 11 complementation groups are sensitive to UV or X rays in addition to MMS, mutants of six complementation groups are sensitive to all three agents. The cross-sensitivities of these mms mutants to UV and X rays are discussed in terms of their possible involvement in DNA repair. Sporulation is reduced or absent in homozygous diploids of mms mutants from nine complementation groups.
Insights
Researchers identified new methyl methanesulfonate (MMS) sensitive mutants in yeast. Many of these mutants reveal novel genes involved in DNA repair pathways, impacting cellular resistance and reproduction.
Area of Science:
- Molecular Biology
- Genetics
- Yeast Genetics
Background:
- Methyl methanesulfonate (MMS) is a potent DNA alkylating agent, necessitating robust cellular defense mechanisms.
- Understanding DNA repair pathways is crucial for comprehending cellular responses to genotoxic stress.
Purpose of the Study:
- To isolate and characterize novel mutants in Saccharomyces cerevisiae exhibiting sensitivity to methyl methanesulfonate (MMS).
- To investigate the genetic basis of MMS sensitivity and its relationship with other DNA repair pathways.
Main Methods:
- Isolation of MMS-sensitive mutants in Saccharomyces cerevisiae.
- Complementation analysis with existing radiation-sensitive (rad and rev) mutants.
- Determination of cross-sensitivity profiles to UV and X-rays.
Main Results:
- Identified 29 MMS-sensitive mutants belonging to 22 new complementation groups.
- Found alleles of known DNA repair genes (rad1, rad4, rad52, rad55, rad57).
- Characterized distinct sensitivity patterns: some mutants were MMS-specific, while others showed cross-sensitivity to UV and X-rays.
Conclusions:
- The study identified novel genes involved in methyl methanesulfonate (MMS) resistance and DNA repair in yeast.
- Cross-sensitivity data suggests the involvement of these new genes in multiple DNA repair pathways.
- Several MMS-sensitive mutants exhibited defects in sporulation, indicating a link between DNA repair and meiotic progression.
