TFIID component TAF7 functionally interacts with both TFIIH and P-TEFb
- Anne Gegonne*,
- Jocelyn D. Weissman*,
- Hanxin Lu*,
- Meisheng Zhou†,
- Arindam Dasgupta†,
- Robert Ribble†,
- John N. Brady†, and
- Dinah S. Singer*,‡
- *Experimental Immunology Branch and
- †Virus Tumor Biology Section, Basic Research Laboratory, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892
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Communicated by Gregory A. Petsko, Brandeis University, Waltham, MA, February 20, 2008 (received for review January 14, 2008)
Abstract
Transcription consists of a series of highly regulated steps: assembly of the preinitiation complex (PIC) at the promoter, initiation, elongation, and termination. PIC assembly is nucleated by TFIID, a complex composed of the TATA-binding protein (TBP) and a series of TBP-associated factors (TAFs). One component, TAF7, is incorporated in the PIC through its interaction with TFIID but is released from TFIID upon transcription initiation. We now report that TAF7 interacts with the transcription factors, TFIIH and P-TEFb, resulting in the inhibition of their Pol II CTD kinase activities. Importantly, in in vitro transcription reactions, TAF7 inhibits steps after PIC assembly and formation of the first phosphodiester bonds. Further, in vivo TAF7 coelongates with P-TEFb and Pol II downstream of the promoter. We propose a model in which TAF7 contributes to the regulation of the transition from PIC assembly to initiation and elongation.
Footnotes
- ‡To whom correspondence should be addressed. E-mail: dinah.singer{at}nih.gov
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Author contributions: A.G., J.N.B., and D.S.S. designed research; A.G., J.D.W., H.L., and M.Z. performed research; A.D. and R.R. contributed new reagents/analytic tools; A.G., J.D.W., and D.S.S. analyzed data; and A.G. and D.S.S. wrote the paper.
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The authors declare no conflict of interest.
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This article contains supporting information online at www.pnas.org/cgi/content/full/0801637105/DCSupplemental.
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Freely available online through the PNAS open access option.
