title: Mutations in RNA polymerase II enhance or suppress mutations in GAL4.
abstract: The activation domains of eukaryotic DNA-binding transcription factors, such as GAL4, may regulate transcription by contacting RNA polymerase II. One potential site on RNA polymerase II for such interactions is the C-terminal tandemly repeated heptapeptide domain in the largest subunit (RPO21). We have changed the number of heptapeptide repeats in this yeast RPO21 C-terminal domain and have expressed these mutant RNA polymerase II polypeptides in yeast cells containing either wild-type or defective GAL4 proteins. Although the number of RPO21 heptapeptide repeats had no effect on the activity of wild-type GAL4, changing the length of the C-terminal domain modified the ability of mutant GAL4 proteins to activate transcription. Shorter or longer RPO21 C-terminal domains enhanced or partially suppressed, respectively, the effects of deletions in the transcriptional-activation domains of GAL4. The same RPO21 mutations also affected transcriptional activation by a GAL4-GCN4 chimera. These data suggest that the activation domains of DNA-binding transcription factors could interact, either directly or indirectly, with the heptapeptide repeats of RNA polymerase II.
authors.affiliation: Banting and Best Department of Medical Research, University of Toronto, ON, Canada.
authors.forename: L A
authors.initials: LA
authors.lastname: Allison
authors.forename: C J
authors.initials: CJ
authors.lastname: Ingles
mesh_terms: D000595:Amino Acid Sequence; D004252:DNA Mutational Analysis; D004268:DNA-Binding Proteins / Q000235:genetics*; D012319:RNA Polymerase II / Q000235:genetics* / Q000276:immunology; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D013329:Structure-Activity Relationship; D013489:Suppression, Genetic; D014157:Transcription Factors / Q000235:genetics*; D014158:Transcription, Genetic; D001616:beta-Galactosidase / Q000235:genetics
chemical_list: D004268:DNA-Binding Proteins; D014157:Transcription Factors; D012319:RNA Polymerase II; D001616:beta-Galactosidase