Schiestl R H, Gietz R D, Hastings P J, Wintersberger U
Department of Tumor Biology-Cancer Research, University of Vienna, Wien, Austria.
Mol Gen Genet. 1990 Jun;222(1):25-32. doi: 10.1007/BF00283018.
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.
在RAD18、rad18缺失和rad18 - 3突变菌株中测定了染色体内和染色体间重组的频率。结果发现，与RAD +菌株相比，rad18 - 3和rad18缺失突变体中trp5、his1、ade2和MAT位点的自发染色体间重组频率提高了10至70倍。另一方面，rad18缺失突变体中his3δ3'、his3δ5'以及his4C -、his4A -重复序列的自发染色体内重组频率和异宗配合型转换频率仅略有升高，而rad18 - 3突变体中核糖体DNA重复序列之间的重组频率仅升高了2倍。这些差异可能是由于单倍体与二倍体的特异性差异。然而，在rad18缺失的纯合二倍体中，染色体间重组频率提高了40倍，而染色体内重组频率仅略有升高（1.5倍），这与单倍体与二倍体的特异性差异不符。文中讨论了染色体内与染色体间自发重组水平升高差异的可能解释。
