A role of the TATA box and the general co-activator hTAF(II)130/135 in promoter-specific trans-activation by simian virus 40 small t antigen.
The small t antigen (st-ag) of simian virus 40 can exert pleiotropic effects on biological processes such as DNA replication, cell cycle progression and gene expression. One possible mode of achieving these effects is through stimulation of NFkappaB-responsive genes encoding growth factors, cytokines, transcription factors and cell cycle regulatory proteins. Indeed, a previous study has shown that st-ag enhanced NFkappaB-mediated transcription. This study demonstrates that promoters possessing a consensus TATA box (i.e. TATAAAAG) in the context of either NFkappaB- or Sp1-binding sites are trans-activated by st-ag. Overexpressing the general transcription factor hTAF(II)130/135, but not hTAF(II)28 or hTAF(II)80, stimulated the activity of promoters in a consensus TATA box-dependent mode. Converting the consensus TATA motif into a non-consensus TATA box strongly impaired activation by st-ag and hTAF(II)130/135. Conversely, mutating a non-consensus TATA motif into the consensus TATA box rendered the mutated promoter inducible by st-ag and hTAF(II)130/135. Mutation of the TATA box had no effect on TNFalpha- or RelA/p65-mediated induction of NFkappaB-responsive promoters, indicating a specific st-ag effect on hTAF(II)130/135. St-ag stimulated the intrinsic transcriptional activity of hTAF(II)130/135. Substitutions in the conserved HPDKGG motif in the N-terminal region or a mutation that impaired the interaction with protein phosphatase 2A abrogated the ability of st-ag to activate hTAF(II)130/135-mediated transcription. These results indicate that trans-activation of promoters by st-ag may depend on a consensus TATA motif and suggest that such promoters recruit the general transcription factor hTAF(II)130/135.
Johannessen
Mona
M
Department of Biochemistry, Section for Molecular Genetics, Institute of Medical Biology, University of Tromsø, N-9037 Tromsø, Norway.
Olsen
Petter Angell
PA
Department of Biochemistry, Section for Molecular Genetics, Institute of Medical Biology, University of Tromsø, N-9037 Tromsø, Norway.
Sørensen
Rita
R
Department of Biochemistry, Section for Molecular Genetics, Institute of Medical Biology, University of Tromsø, N-9037 Tromsø, Norway.
Johansen
Bjarne
B
Department of Biochemistry, Section for Molecular Genetics, Institute of Medical Biology, University of Tromsø, N-9037 Tromsø, Norway.
Seternes
Ole Morten
OM
Department of Biochemistry, Section for Molecular Genetics, Institute of Medical Biology, University of Tromsø, N-9037 Tromsø, Norway.
Moens
Ugo
U
Department of Biochemistry, Section for Molecular Genetics, Institute of Medical Biology, University of Tromsø, N-9037 Tromsø, Norway.
D016475:3T3 Cells; D000818:Animals; D000952:Antigens, Polyomavirus Transforming / Q000502:physiology*; D001483:Base Sequence; D005786:Gene Expression Regulation; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D016328:NF-kappa B / Q000235:genetics / Q000378:metabolism; D011401:Promoter Regions, Genetic / Q000235:genetics*; D013539:Simian virus 40 / Q000276:immunology* / Q000472:pathogenicity; D016385:TATA Box / Q000502:physiology*; D035381:TATA-Binding Protein Associated Factors / Q000235:genetics / Q000378:metabolism*; D035362:Transcription Factor TFIID / Q000235:genetics / Q000378:metabolism*; D015533:Transcriptional Activation
D000952:Antigens, Polyomavirus Transforming; D016328:NF-kappa B; C101882:TAF4 protein, human; C523528:TAF4 protein, mouse; D035381:TATA-Binding Protein Associated Factors; D035362:Transcription Factor TFIID