c-Jun binds the N terminus of human TAF(II)250 to derepress RNA polymerase II transcription in vitro.
c-Jun is an oncoprotein that activates transcription of many genes involved in cell growth and proliferation. We studied the mechanism of transcriptional activation by human c-Jun in a human RNA polymerase II transcription system composed of highly purified recombinant and native transcription factors. Transcriptional activation by c-Jun depends on the TATA-binding protein (TBP)-associated factor (TAF) subunits of transcription factor IID (TFIID). Protein-protein interaction assays revealed that c-Jun binds with high specificity to the largest subunit of human TFIID, TAF(II)250. The region of TAF(II)250 bound by c-Jun lies in the N-terminal 163 amino acids. This same region of TAF(II)250 binds to TBP and represses its interaction with TATA boxes, thereby decreasing DNA binding by TFIID. We hypothesized that c-Jun is capable of derepressing the effect of the TAF(II)250 N terminus on TFIID-driven transcription. In support of this hypothesis, we found that c-Jun increased levels of TFIID-driven transcription in vitro when added at high concentrations to a DNA template lacking activator protein 1 (AP-1) sites. Moreover, c-Jun blocked the repression of TBP DNA binding caused by the N terminus of TAF(II)250. In addition to revealing a mechanism by which c-Jun activates transcription, our studies provide the first evidence that an activator can bind directly to the N terminus of TAF(II)250 to derepress RNA polymerase II transcription in vitro.
Lively
T N
TN
Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO 80309-0215, USA.
Ferguson
H A
HA
Galasinski
S K
SK
Seto
A G
AG
Goodrich
J A
JA
D002846:Chromatography, Affinity; D004247:DNA / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D004789:Enzyme Activation; D004926:Escherichia coli; D051548:Histone Acetyltransferases; D006801:Humans; D009687:Nuclear Proteins / Q000378:metabolism*; D010957:Plasmids; D011485:Protein Binding; D016755:Proto-Oncogene Proteins c-jun / Q000378:metabolism*; D012319:RNA Polymerase II / Q000378:metabolism*; D013379:Substrate Specificity; D035381:TATA-Binding Protein Associated Factors; D018808:Transcription Factor AP-1 / Q000378:metabolism; D035362:Transcription Factor TFIID; D015533:Transcriptional Activation
D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; D016755:Proto-Oncogene Proteins c-jun; D035381:TATA-Binding Protein Associated Factors; D018808:Transcription Factor AP-1; D035362:Transcription Factor TFIID; D004247:DNA; D051548:Histone Acetyltransferases; C069001:TATA-binding protein associated factor 250 kDa; D012319:RNA Polymerase II