Effect of pre-treatment with 5-bromouracil in an ultraviolet sensitive strain ofNeurospora crassa

Abstract

SUMMARY5-Bromouracil was shown to enhance the mutation frequency in an ultraviolet sensitive strain ofNeurospora crassa (uvs-2) that was previously irradiated with ultraviolet light. The design of the experiment eliminated light or dark repair as possible hypotheses to account for the observed enhancement. Since a similar effect was noted at therib-1 locus inN. crassa, which is not a UV-sensitive strain, it appears that the error prone repair mechanism inN. crassamay be related to post-replication repair. This enhancement may be attributed to the interference of 5-bromouracil with post-replication repair. It is also postulated that the maximum increase in the mutation frequency occurs when the greatest number of unrepaired pre-mutational UV lesions are repaired in the presence of 5-bromouracil.