Temperature-sensitive mutant of Schizosaccharomyces pombe exhibiting enhanced radiation sensitivity

Abstract

A conditional lethal and radiation-sensitive mutant of Schizosaccharomyces pombe is described in which both characteristics result from a single gene mutation. Confirmation of the pleiotropic nature of this mutant was obtained by tetrad analysis and by testing the radiation sensitivity of a large number of revertants that grew normally at the restrictive temperature. The colony-forming ability of the mutant after ultraviolet radiation, gamma radiation, and ethyl methane sulfonate treatment is considerably altered by the post-treatment incubation temperature, showing higher survival at 25 than at 30degreesC. The radiosensitivity of the mutant is also influenced by the stage of growth. The difference in radiation sensitivity between the wild type and mutant is greater when log-phase cultures are compared. The characteristics of this mutant suggest that it is defective in a step common to both deoxyribonucleic acid replication and repair.

Cloning and characterization of therad4gene ofSchizosaccharomyces pombe; a gene showing short regions of sequence similarity to the human XRCC1 gene

“…Pulse field gel electrophoresis studies reported elsewhere (24) have shown that the gene is located on the 1.2 Mb Not I fragment D (25) on chromosome 1. The complete gene is able to correct both the temperature-sensitivity of the rad4.116 mutant and its UV sensitivity (Figure 3), confirming that both these properties result from a single mutation (7). The first plasmid that we identified by its ability to complement the temperature sensitivity of the rad4.116 mutant contained a truncated gene, missing the Cterminal 37 amino acids.…”

“…The cells have a very high level of sister chromatid exchanges and a reduced rate ofjoining singlestrand breaks following treatment with ionizing radiation or ethyl methanesulphonate (26). In contrast, the hypersensitivities of the rad4 mutant to UV, -y-rays and EMS were similar for each mutagen (7). No biochemical characterisation of the defect in rad4 mutants has been reported.…”

Duplicated region of sequence similarity to the humanXRCC1DNA repair gene in the Schizosaccharomyces pomberad4/cut5gene

“…Mutation in the rad4 gene of Schizosaccharomyces pombe confers sensitivity to both UV and ionizing radiation damage, as well as a temperature-sensitive phenotype (1). We previously reported the cloning of the rad4 gene (EMBL Accession no.…”