Similar upstream regulatory elements of genes that encode the two largest subunits of RNA polymerase II in Saccharomyces cerevisiae

Abstract

We have determined the location of cis-acting elements that are important for the expression of RP021 and RP022, genes that encode the two largest subunits of RNA polymerase II (RNAPII) in Saccharomyces cerevisiae. A series of 5'-end deletions and nucleotide substitutions in the upstream regions of RP021 and RP022 were tested for their effect on the expression of lacZ fusions of these genes. Deletion of sequences from -723 to -693 in RP021, which disrupted two Reb1p-binding sites and an Abf1p-binding site, resulted in a 10-fold decrease in expression. A T-rich region downstream of these sites was also important for expression. Deletion of sequences from -437 to -392 in the RP022-upstream, which resulted in a 30-fold decrease in expression, indicated that the Reb1p- and Abf1p-binding sites in this region were important for RP022 expression, as was a T-rich sequence immediately downstream of these sites. The RP021 and RP022 upstream regions were capable of interacting in vitro (gel-mobility-shift assays) with Reb1p and Abf1p. The similarities in the type and organization of elements in the upstream regions of RP021 and RP022 suggest that expression of these genes may be regulated coordinately.