Meiotic Gene Conversion Mutants in SACCHAROMYCES CEREVISIAE . I. Isolation and Characterization of pms1-1 and pms1-2
AUTOR(ES)
Williamson, Marsha S.
RESUMO
The pms1 mutants, isolated on the basis of sharply elevated meiotic prototroph frequencies for two closely linked his4 alleles, display pleiotropic phenotypes in meiotic and mitotic cells. Two isolates carrying recessive mutations in PMS1 were characterized. They identify a function required to maintain low postmeiotic segregation (PMS) frequencies at many heterozygous sites. In addition, they are mitotic mutators. In mutant diploids, spore viability is reduced, and among survivors, gene conversion and postmeiotic segregation frequencies are increased, but reciprocal exchange frequencies are not affected. The conversion event pattern is also dramatically changed in multiply marked regions in pms1 homozygotes. The PMS1 locus maps near MET4 on chromosome XIV. The PMS1 gene may identify an excision-resynthesis long patch mismatch correction function or a function that facilitates correction tract elongation. The PMS1 gene product may also play an important role in spontaneous mitotic mutation avoidance and correction of mismatches in heteroduplex DNA formed during spontaneous and UV-induced mitotic recombination. Based on meiotic recombination models emphasizing mismatch correction in heteroduplex DNA intermediates, this interpretation is favored, but alternative interpretations involving longer recombination intermediates in the mutants are also considered.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1202584Documentos Relacionados
- Mutations Affecting Sexual Conjugation and Related Processes in SACCHAROMYCES CEREVISIAE. I. Isolation and Phenotypic Characterization of Nonmating Mutants
- 2-Deoxyribose Gene-Enzyme Complex in Salmonella typhimurium I. Isolation and Enzymatic Characterization of 2-Deoxyribose-Negative Mutants1
- Meiosis in Male DROSOPHILA MELANOGASTER I. Isolation and Characterization of Meiotic Mutants Affecting Second Chromosome Disjunction
- Physical Lengths of Meiotic and Mitotic Gene Conversion Tracts in Saccharomyces Cerevisiae
- Mutators in SACCHAROMYCES CEREVISIAE: MUT1–1, MUT1–2 and MUT2–1