Analysis of mitotic and meiotic defects in Saccharomyces cerevisiae SRS2 DNA helicase mutants.

The hyper-gene conversion srs2-101 mutation of the SRS2 DNA helicase gene of Saccharomyces cerevisiae has been reported to suppress the UV sensitivity of rad18 mutants. New alleles of SRS2 were recovered using this suppressor phenotype. The alleles have been characterized with respect to suppression of rad18 UV sensitivity, hyperrecombination, reduction of meiotic viability, and definition of the mutational change within the SRS2 gene. Variability in the degree of rad18 suppression and hyperrecombination were found. The alleles that showed the severest effects were found to be missense mutations within the consensus domains of the DNA helicase family of proteins. The effect of mutations in domains I (ATP-binding) and V (proposed DNA binding) are reported. Some alleles of SRS2 reduce spore viability to 50% of wild-type levels. This phenotype is not bypassed by spo13 mutation. Although the srs2 homozygous diploids strains undergo normal commitment to meiotic recombination, this event is delayed by several hours in the mutant strains and the strains appear to stall in the progression from meiosis I to meiosis II.

[1]  T. Hodgman,et al.  A new superfamily of replicative proteins , 1988, Nature.

[2]  S. Kohalmi,et al.  Role of neighbouring bases and assessment of strand specificity in ethylmethanesulphonate and N-methyl-N'-nitro-N-nitrosoguanidine mutagenesis in the SUP4-o gene of Saccharomyces cerevisiae. , 1988, Journal of molecular biology.

[3]  M. Resnick,et al.  The Role of Radiation (rad) Genes in Meiotic Recombination in Yeast. , 1980, Genetics.

[4]  H. Klein.  Different types of recombination events are controlled by the RAD1 and RAD52 genes of Saccharomyces cerevisiae. , 1988, Genetics.

[5]  R. Knippers,et al.  DNA helicase activity of SV40 large tumor antigen. , 1986, The EMBO journal.

[6]  M. Hoekstra,et al.  Relationships between a hyper-rec mutation (REM1) and other recombination and repair genes in yeast. , 1984, Genetics.

[7]  Z. Horii,et al.  Genetic analysis of the recF pathway to genetic recombination in Escherichia coli K12: isolation and characterization of mutants. , 1973, Journal of molecular biology.

[8]  A. Mildvan,et al.  ATP-binding site of adenylate kinase: mechanistic implications of its homology with ras-encoded p21, F1-ATPase, and other nucleotide-binding proteins. , 1986, Proceedings of the National Academy of Sciences of the United States of America.

[9]  S. Fogel,et al.  Meiotic recombination and sporulation in repair-deficient strains of yeast. , 1985, Genetics.

[10]  R. E. Esposito,et al.  Recombination and chromosome segregation during the single division meiosis in SPO12-1 and SPO13-1 diploids. , 1980, Genetics.

[11]  R. E. Esposito,et al.  Recombinationless meiosis in Saccharomyces cerevisiae , 1981, Molecular and cellular biology.

[12]  J. Beggs,et al.  A suppressor of a yeast splicing mutation (prp8-l) encodes a putative ATP-dependent RNA helicase , 1991, Nature.

[13]  R. Schiestl,et al.  The SRS2 suppressor of rad6 mutations of Saccharomyces cerevisiae acts by channeling DNA lesions into the RAD52 DNA repair pathway. , 1990, Genetics.

[14]  F. Winston,et al.  A ten-minute DNA preparation from yeast efficiently releases autonomous plasmids for transformation of Escherichia coli. , 1987, Gene.

[15]  N. M. Hollingsworth,et al.  HOP1: a yeast meiotic pairing gene. , 1989, Genetics.