THE YEAST ALPHA-2 PROTEIN CAN REPRESS TRANSCRIPTION BY RNA POLYMERASE-I AND POLYMERASE-II BUT NOT POLYMERASE-III

The alpha2 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 alpha2 can affect transcription by other RNA polymerases. We find that alpha2 can repress transcription by RNA polymerase I but not by RNA polymerase III. Additional experiments indicate that alpha2 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 alpha2 repression and exclude several alternate models.