A highly conserved domain of RNA polymerase II shares a functional element with acidic activation domains of upstream transcription factors.
We report here that the largest subunit of yeast RNA polymerase II contains an acidic domain that is similar to acidic activators of transcription. This domain includes the highly conserved homology box H. A hybrid protein containing this acidic domain fused to the DNA-binding domain of GAL4 is a potent activator of transcription in the yeast Saccharomyces cerevisiae. Interestingly, mutations that reduce the upstream activating activity of this acidic domain also abolish the normal function of RNA polymerase II. Such functional defects can be rescued by the acidic activation domains of VP16 and GAL4 when inserted into the mutant derivatives of RNA polymerase II. We further show that this acidic domain of RNA polymerase II interacts directly with two general transcription factors, the TATA-binding protein and TFIIB, and that the acidic activation domain of VP16 can compete specifically with the acidic domain of the RNA polymerase for these interactions. We discuss the implications of this finding for the mechanisms of transcriptional activation in eucaryotes.
Xiao
H
H
Department of Genetics, Hospital for Sick Children, University of Toronto, Ontario, Canada.
Friesen
J D
JD
Lis
J T
JT
D000595:Amino Acid Sequence; D001483:Base Sequence; D017124:Conserved Sequence; D004271:DNA, Fungal / Q000235:genetics; D004268:DNA-Binding Proteins / Q000378:metabolism; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D008954:Models, Biological; D008969:Molecular Sequence Data; D011487:Protein Conformation; D012319:RNA Polymerase II / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins; D017386:Sequence Homology, Amino Acid; D035181:TATA-Box Binding Protein; D035581:Transcription Factor TFIIB; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism*; D015533:Transcriptional Activation
D004271:DNA, Fungal; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; C052130:GAL4 protein, S cerevisiae; D011993:Recombinant Fusion Proteins; D029701:Saccharomyces cerevisiae Proteins; D035181:TATA-Box Binding Protein; D035581:Transcription Factor TFIIB; D014157:Transcription Factors; D012319:RNA Polymerase II