The Yeast α2 Protein Can Repress Transcription by RNA Polymerases I and II but Not III

Abstract

The α2 protein of the yeast Saccharomyces cerevisiae normally represses a set of cell-type-specific genes (the a-specific genes) that are transcribed by RNA polymerase II. In this study, we determined whether α2 can affect transcription by other RNA polymerases. We find that α2 can repress transcription by RNA polymerase I but not by RNA polymerase III. Additional experiments indicate that α2 represses RNA polymerase I transcription through the same pathway that it uses to repress RNA polymerase II transcription. These results implicate conserved components of the transcription machinery as mediators of α 2 repression and exclude several alternate models.