Drosophila TAFII40 interacts with both a VP16 activation domain and the basal transcription factor TFIIB.
Enhancement of RNA polymerase II transcription by the viral transactivator VP16 requires the TFIID complex, which consists of the TATA-binding protein (TBP) and TBP-associated factors (TAFs). Here we report the molecular cloning, expression, and biochemical characterization of Drosophila TAFII40 (dTAFII40), a subunit of TFIID. In vitro protein-protein interaction assays revealed direct binding between dTAFII40 and a 39 amino acid VP16 activation domain. In addition, affinity chromatography indicated a direct binding of the basal factor TFIIB to immobilized dTAFII40. Since VP16 also binds TFIIB, our results suggest a ternary interaction among an activator, a coactivator, and a basal transcription factor. Antibodies directed against dTAFII40 inhibited activation by GAL4-VP16 without affecting basal transcription. These results, taken together with previous studies of Sp1 and dTAFII110, establish that different activators interact with distinct TAFs in the TFIID complex and that TAFs can contact both activators and basal factors.
Goodrich
J A
JA
Howard Hughes Medical Institute, Department of Molecular and Cell Biology, University of California, Berkeley 94720.
Hoey
T
T
Thut
C J
CJ
Admon
A
A
Tjian
R
R
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D004268:DNA-Binding Proteins / Q000378:metabolism; D004330:Drosophila / Q000235:genetics*; D029721:Drosophila Proteins; D017405:Herpes Simplex Virus Protein Vmw65 / Q000378:metabolism; D006801:Humans; D008957:Models, Genetic; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000378:metabolism; D011994:Recombinant Proteins / Q000096:biosynthesis; D017422:Sequence Analysis, DNA; D035381:TATA-Binding Protein Associated Factors; D035181:TATA-Box Binding Protein; D015534:Trans-Activators / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D035581:Transcription Factor TFIIB; D035362:Transcription Factor TFIID; D014157:Transcription Factors / Q000378:metabolism*; D014158:Transcription, Genetic
D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D017405:Herpes Simplex Virus Protein Vmw65; D010446:Peptide Fragments; D011994:Recombinant Proteins; D035381:TATA-Binding Protein Associated Factors; D035181:TATA-Box Binding Protein; D015534:Trans-Activators; D035581:Transcription Factor TFIIB; D035362:Transcription Factor TFIID; D014157:Transcription Factors; C084120:e(y)1 protein, Drosophila