Interchromosomal and intrachromosomal recombination in rad 18 mutants of Saccharomyces cerevisiae.
The frequency of intra- and interchromosomal recombination was determined in RAD18 and rad18 deletion and rad18-3 mutant strains. It was found that spontaneous interchromosomal recombination at trp5, his1, ade2, and MAT was elevated 10- to 70-fold in the rad18-3 and rad18 delta mutants as compared to the RAD+ strains. On the other hand the frequencies of spontaneous intrachromosomal recombination for the his3 delta 3', his3 delta 5' and the his4C-, his4A- duplications and for heterothallic mating type switching were only marginally elevated in the rad18 deletion mutant, and recombination between ribosomal DNA repeats was only 2-fold elevated in the rad18-3 mutant. These differences may be due to a haploid versus diploid specific difference. However interchromosomal recombination was elevated 40-fold and intrachromosomal recombination was only marginally (1.5-fold) elevated in a diploid homozygous for rad18 delta, arguing against a haploid versus diploid specific difference. Possible explanations for the difference in the elevated levels of intra- versus interchromosomal spontaneous recombination are discussed.
Schiestl
R H
RH
Department of Tumor Biology-Cancer Research, University of Vienna, Wien, Austria.
Gietz
R D
RD
Hastings
P J
PJ
Wintersberger
U
U
D015825:Chromosomes, Fungal; D004260:DNA Repair; D004171:Diploidy; D005800:Genes, Fungal; D049770:Genes, Mating Type, Fungal; D005838:Genotype; D009154:Mutation; D011995:Recombination, Genetic; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000528:radiation effects; D012854:Sister Chromatid Exchange; D014466:Ultraviolet Rays