Incision of UV (Ultraviolet) Irradiated DNA in Yeast: Progress Report, November 1, 1988-June 7, 1989

摘要

Our objectives are to determine the details of the incision step of excision repair following exposure to UV light in the eucaryotic organism, the yeast Saccharomyces cerevisiae. We have focused on three of the ten genes involved in this process -- RAD1, RAD3, and RAD10. We have purified RAD3 protein to near homogeneity, and it possesses single-stranded DNA-dependent ATPase activity and DNA helicase activity which translocates in the 5' implies 3' direction. Site-directed mutagenesis was used to change amino acid residues in a region thought to be required for nucleotide binding and the biological effects of these mutations determined. RAD1 protein is also being purified and RAD10 protein has been purified to near homogeneity. We can now begin to examine RAD10's role in excision repair. A conserved pattern of antisense overlapping transcription has been noted in the yeast RAD10 gene region and in the homologous human ERCC-1 gene. Analysis of the overlapping genes in this region has been carried out. The human RAD3 homolog ERCC-2 is also being studied. Since defective DNA repair and enhanced neoplasia characterize several human genetic diseases, a thorough understanding of the molecular mechanisms of DNA repair may provide a better understanding of the causes of carcinogenesis.