REPLICATION PROTEIN-A BINDS TO REGULATORY ELEMENTS IN YEAST DNA-REPAIR AND DNA METABOLISM GENES

Saccharomyces cerevisiae responds to DNA damage by arresting cell cycl e progression (thereby preventing the replication and segregation of d amaged chromosomes) and by inducing the expression of numerous genes, some of which are involved in DNA repair, DNA replication, and DNA met abolism. Induction of the S. cerevisiae 3-methyladenine DNA glycosylas e repair gene (MAG) by DNA-damaging agents requires one upstream activ ating sequence (UAS) and two upstream repressing sequences (URS1 and U RS2) in the MAG promoter. Sequences similar to the MAG URS elements ar e present in at least 11 other S. cerevisiae DNA repair and metabolism genes. Replication protein A (Rpa) is known as a single-stranded-DNA- binding protein that is involved in the initiation and elongation step s of DNA replication, nucleotide excision repair, and homologous recom bination. We now show that the MAG URS1 and URS2 elements form similar double-stranded, sequence-specific, DNA-protein complexes and that bo th complexes contain Rpa. Moreover, Rpa appears to bind the MAG URS1-l ike elements found upstream of 11 other DNA repair and DNA metabolism genes. These results lead us to hypothesize that Rpa may be involved i n the regulation of a number of DNA repair and DNA metabolism genes.