MUTANTS WITH CHANGES IN DIFFERENT DOMAINS OF YEAST REPLICATION PROTEIN-A EXHIBIT DIFFERENCES IN REPAIRING THE CONTROL REGION, THE TRANSCRIBED STRAND AND THE NONTRANSCRIBED STRAND OF THE SACCHAROMYCES-CEREVISIAE MFA2 GENE

We have analysed the removal of W-induced cyclobutane pyrimidine dimer s (CPDs) at nucleotide resolution from the MFA2 gene of wild-type Sacc haromyces cerevisiae and in strains harbouring mutations in one of the yeast replication protein A (RPA) genes, RFA1. This gene codes for th e 70 kDa subunit of RPA and it has previously been shown to have a rol e in nucleotide excision repair. Here two RFA1 mutants were examined: rfa1-M2 which is mutated in the protein interaction domain and rfa1-M4 which is mutated in the DNA-binding domain. A distinct difference in the removal of CPDs from the MFA2 sequence of these two mutants was ob served. Compared to the parental st-rain, there was no defect in CPD r emoval in the rfa1-M2 mutant. Contrarily, the rfa1-M4 mutant was total ly defective in the global repair of CPDs from the non-transcribed str and and the non-transcribed portions of the strand containing the tran scribed sequence, yet it was able to perform reduced transcription cou pled repair of the transcribed strand. These results indicate that the role of the DNA-binding domain of RPA is different for global repair versus transcription coupled nucleotide excision repair. (C) 1998 Acad emic Press.