TI  - Interaction with <prot>RAP74</prot> subunit of <prot>TFIIF</prot> is required for transcriptional
      activation by <prot>serum response factor</prot>.
PG  - 632-5
AB  - A few general transcription factors, in particular <prot>TFIID</prot> and <prot>TFIIB</prot>, have
      been found to bind transcriptional activators. Here we show that the
      general transcription factor  <prot>TFIIF</prot>  is also a target for a transcriptional
      activator, namely   <prot>serum response factor</prot> (<prot>SRF</prot>)  , which binds to the  <prot>c-fos</prot> 
      promoter. Using a yeast interaction assay, we find that   <prot>SRF</prot>   binds the
       <prot>RAP74</prot>  subunit of  <prot>TFIIF</prot>  and that <prot>SRF</prot>'s transcriptional activation domain is
      the region involved in this binding. Further,  <prot>RAP74</prot> 's central charged
      cluster domain is required for binding to  <prot>SRF</prot> 's activation domain.
      Deletion of this domain impairs <prot>RAP74</prot>'s ability to support <prot>SRF</prot>-activated
      transcription in vitro but has little effect on the protein's basal
      transcription activity or its ability to support <prot>SP1</prot>-activated
      transcription. The correlation of  <prot>SRF</prot> - <prot>RAP74</prot>  binding with transcriptional
      activation suggests that <prot>RAP74</prot> is a critical target for <prot>SRF</prot>-activated
      transcription.
AD  - Department of Biological Sciences, Columbia University, New York, New York
