Temperature-sensitive mutant of Schizosaccharomyces pombe exhibiting enhanced radiation sensitivity

Abstract

A conditional lethal and radiation-sensitive mutant of S. pombe is described in which both characteristics result from a single gene mutation. Confirmation of the pleiotropic nature of this mutation 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 UV radiation, .gamma. radiation, and ethyl methane sulfonate treatment is considerably altered by the post-treatment incubation temperature, showing higher survival at 25 than at 30.degree. C. 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 DNA replication and repair.