Drosophila TAF(II)230 and the transcriptional activator VP16 bind competitively to the TATA box-binding domain of the TATA box-binding protein.
The transcription initiation factor TFIID, consisting of the TATA box-binding protein (TBP) and many TBP-associated factors (TAFs), plays a central role in both basal and activated transcription. An intriguing finding is that the 80-residue N-terminal region of Drosophila TAF(II)230 [dTAF(II)230-(2-81)] can bind directly to TBP and inhibit its function. Here, studies with mutated forms of TBP demonstrate that dTAF(II)230-(2-81) binds to the concave surface of TBP, which is important for TATA box binding. Previously, it was reported that a point mutation (L114K) on this concave surface destroys the ability of TBP to bind VP16 and to mediate VP16-dependent activation in vitro, but has no effect on basal transcription. Importantly, the same TBP mutation eliminates TBP binding to dTAF(II)230-(2-81). Consistent with these effects of the L114K mutation, dTAF(II)230-(2-81) and the VP16 activation domain compete for binding to wild-type TBP. These results indicate that transcriptional regulation may involve, in part, competitive interactions between transcriptional activators and TAFs on the TBP surface.
Nishikawa
J
J
Laboratory of Molecular Growth Regulation, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA.
Kokubo
T
T
Horikoshi
M
M
Roeder
R G
RG
Nakatani
Y
Y
D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D001667:Binding, Competitive; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004330:Drosophila; D029721:Drosophila Proteins; D017405:Herpes Simplex Virus Protein Vmw65 / Q000378:metabolism*; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000378:metabolism*; D011485:Protein Binding; D016385:TATA Box; D035181:TATA-Box Binding Protein; D035362:Transcription Factor TFIID; D014157:Transcription Factors / Q000378:metabolism*; D019473:Transcription Factors, TFII / Q000378:metabolism*
D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D017405:Herpes Simplex Virus Protein Vmw65; D010446:Peptide Fragments; C103705:TAFII230 (2-81), Drosophila; D035181:TATA-Box Binding Protein; D035362:Transcription Factor TFIID; D014157:Transcription Factors; D019473:Transcription Factors, TFII