Reconstitution of Transcription Factor SL1: Exclusive Binding of TBP by SL1 or TFIID Subunits
Abstract
RNA polymerase I and II transcription factors SL1 and TFIID, respectively, are composed of the TATA-binding protein (TBP) and a set of TBP-associated factors (TAFs) responsible for promoter recognition. How the universal transcription factor TBP becomes committed to a TFIID or SL1 complex has not been known. Complementary DNAs encoding each of the three TAF_Is that are integral components of SL1 have now been isolated. Analysis of subunit interactions indicated that the three TAF_Is can bind individually and specifically to TBP. In addition, these TAF_Is interact with each other to form a stable TBP-TAF complex. When TBP was bound first by either TAF_I110, 63, or 48, subunits of TFIID such as TAFII250 and 150 did not bind TBP. Conversely, if TBP first formed a complex with TAFII250 or 150, the subunits of SL1 did not bind TBP. These results suggest that a mutually exclusive binding specificity for TBP intrinsic to SL1 and TFIID subunits directs the formation of promoter- and RNA polymerase-selective TBP-TAF complexes.
- Publication:
-
Science
- Pub Date:
- December 1994
- DOI:
- 10.1126/science.7801123
- Bibcode:
- 1994Sci...266.1966C