The role of mismatch repair in the prevention of base pair mutations in Saccharomyces cerevisiae
AUTOR(ES)
Earley, Marie C.
FONTE
The National Academy of Sciences
RESUMO
In most organisms, the mismatch repair (MMR) system plays an important role in substantially lowering mutation rates and blocking recombination between nonidentical sequences. In Saccharomyces cerevisiae, the products of three genes homologous to Escherichia coli mutS—MSH2, MSH3, and MSH6—function in MMR by recognizing mispaired bases. To determine the effect of MMR on single-base pair mismatches, we have measured reversion rates of specific point mutations in the CYC1 gene in both wild-type and MMR-deficient strains. The reversion rates of all of the point mutations are similar in wild-type cells. However, we find that in the absence of MSH2 or MSH6, but not MSH3, reversion rates of some mutations are increased by up to 60,000-fold, whereas reversion rates of other mutations are essentially unchanged. When cells are grown anaerobically, the reversion rates in MMR-deficient strains are decreased by as much as a factor of 60. We suggest that the high reversion rates observed in these MMR-deficient strains are caused by misincorporations opposite oxidatively damaged bases and that MMR normally prevents these mutations. We further suggest that recognition of mispairs opposite damaged bases may be a more important role for MMR in yeast than correction of errors opposite normal bases.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=28069Documentos Relacionados
- Repair of specific base pair mismatches formed during meiotic recombination in the yeast Saccharomyces cerevisiae.
- The Prevention of Repeat-Associated Deletions in Saccharomyces Cerevisiae by Mismatch Repair Depends on Size and Origin of Deletions
- Some Features of Base Pair Mismatch and Heterology Repair in Escherichia coli
- Evidence for short-patch mismatch repair in Saccharomyces cerevisiae
- Single base-pair mutations in centromere element III cause aberrant chromosome segregation in Saccharomyces cerevisiae.