Role of transcription factor TFIIF in serum response factor-activated transcription.
We have found that the general transcription factor TFIIF has an important role in serum response factor (SRF)-activated transcription in vitro. A low amount of TFIIF was sufficient for basal transcription, whereas higher amounts were required for SRF, but not Sp1, activation. High TFIIF levels also increased activation by GAL4-VP16, whereas none of the other general transcription factors had these properties. TFIIF could also relieve squelching by SRF in vitro, suggesting that SRF may directly bind TFIIF. We found more direct evidence for SRF-TFIIF interaction by DNA binding assays where the RAP74 subunit of TFIIF bound DNA in conjunction with SRF, but not alone. RAP74 also bound DNA with GAL4-VP16, but not with Sp1 or the DNA binding domain of GAL4. These results suggest that the mechanism of transcriptional activation by SRF, and perhaps some other activators, involves their interaction with TFIIF.
Zhu
H
H
Department of Biological Sciences, Columbia University, New York, New York 10027.
Joliot
V
V
Prywes
R
R
D002467:Cell Nucleus / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000302:isolation & purification / Q000378:metabolism* / Q000494:pharmacology*; D015870:Gene Expression / Q000187:drug effects; D006367:HeLa Cells; D006801:Humans; D007700:Kinetics; D046911:Macromolecular Substances; D009687:Nuclear Proteins / Q000494:pharmacology*; D011994:Recombinant Proteins / Q000378:metabolism / Q000494:pharmacology; D026362:Serum Response Factor; D014157:Transcription Factors / Q000302:isolation & purification / Q000378:metabolism*; D019473:Transcription Factors, TFII; D014158:Transcription, Genetic / Q000187:drug effects
D004268:DNA-Binding Proteins; D046911:Macromolecular Substances; D009687:Nuclear Proteins; D011994:Recombinant Proteins; D026362:Serum Response Factor; D014157:Transcription Factors; D019473:Transcription Factors, TFII; C056604:transcription factor TFIIF