Dark repair inhibitors and pathways for repair of radiation damage in Schizosaccharomyces pombe

TLDR: Observations indicate that the presently available radiation sensitive mutants represent defects in only two major pathways for repair of radiation damage in the wild type S. pombe.

Abstract: Different compounds known to inhibit dark repair in bacterial and mammalian systems have been tested for a similar effect in the yeast Schizosaccharomyces pombe. A marked inhibition of growth by these different drugs indicated that these were taken up by the cell, yet none except caffeine reduced the colony forming ability when present in the post-irradiation plating medium. The response of 22 different radiation sensitive mutants to the presence of caffeine in the plating medium was tested to investigate the probable number of pathways for repair of radiation damage in this organism. In some of the genetic crosses among single gene mutants showing a differential caffeine-response, supersensitive double mutants were obtained. Strains obtained either by additional crosses or by further mutagenic treatment of the supersensitive double mutants did not show a highly significant increase in radiation sensitivity. These observations indicate that the presently available radiation sensitive mutants represent defects in only two major pathways for repair of radiation damage in the wild type S. pombe.