TFIID component TAF7 functionally interacts with both TFIIH and P-TEFb.
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.
Gegonne
Anne
A
Experimental Immunology Branch and Virus Tumor Biology Section, Basic Research Laboratory, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA.
Weissman
Jocelyn D
JD
Lu
Hanxin
H
Zhou
Meisheng
M
Dasgupta
Arindam
A
Ribble
Robert
R
Brady
John N
JN
Singer
Dinah S
DS
D002460:Cell Line; D005786:Gene Expression Regulation; D006801:Humans; D046912:Multiprotein Complexes; D042925:Positive Transcriptional Elongation Factor B / Q000378:metabolism*; D011485:Protein Binding; D035381:TATA-Binding Protein Associated Factors / Q000378:metabolism* / Q000502:physiology*; D035362:Transcription Factor TFIID / Q000378:metabolism* / Q000502:physiology; D051758:Transcription Factor TFIIH / Q000378:metabolism*; D014158:Transcription, Genetic; D014162:Transfection
D046912:Multiprotein Complexes; C091537:TAF7 protein, human; D035381:TATA-Binding Protein Associated Factors; D035362:Transcription Factor TFIID; D051758:Transcription Factor TFIIH; D042925:Positive Transcriptional Elongation Factor B