The dTAFII80 subunit of Drosophila TFIID contains β-transducin repeats

• Published in: Nature (London) Vol. 363; no. 6425; pp. 176 - 179
• Main Authors: DYNLACHT, B. D, WEINZIERL, R. O. J, ADMON, A, TJIAN, R
• Format: Journal Article
• Language: English
• Published: London Nature Publishing 13.05.1993; Nature Publishing Group
• Subjects: Amino Acid Sequence; Animals; Arabidopsis - genetics; Biological and medical sciences; Chromosome Mapping; Cloning; Cloning, Molecular; Deoxyribonucleic acid; DNA; DNA-Binding Proteins - chemistry; DNA-Binding Proteins - genetics; Drosophila; Fundamental and applied biological sciences. Psychology; Genetic engineering; Histone Acetyltransferases; Insects; Molecular and cellular biology; Molecular genetics; Molecular Sequence Data; Nuclear Proteins - chemistry; Nuclear Proteins - genetics; Protein Binding; Sequence Homology, Amino Acid; TATA-Binding Protein Associated Factors; Transcription Factor TFIID; Transcription Factors - chemistry; Transcription Factors - genetics; Transcription. Transcription factor. Splicing. Rna processing; Transducin - chemistry; Transducin - genetics; Insecta; Drosophila; Transducin; Homology; Subunit; Drosophilidae; Binding capacity; Arthropoda; DNA; Electrophoretic mobility; Molecular complex; Invertebrata; Molecular cloning; Transcription factor; Diptera; Comparative study; Physicochemical properties; Aminoacid sequence
• ISSN: 0028-0836; 1476-4687
• DOI: 10.1038/363176a0

A key component of the RNA polymerase II transcriptional apparatus, TFIID, is a multi-protein complex containing the TATA box-binding protein (TBP) and at least seven tightly associated factors (TAFs). Although the functions of most TFIID subunits are unknown, it is clear that TAFs are not necessary for basal activity but that one or more are required for regulated transcription, and so behave as coactivators. The presence of multiple subunits indicates that there is an intricate assembly process and that TAFs may be responsible for other activities. We have described the properties of the subunit dTAFII110, which can interact directly with the transcriptional activator Sp1 (ref. 5). In addition, the largest subunit, dTAFII250, binds directly to TBP and links other TAFs to the complex. Here we describe the cloning, expression and partial characterization of the Drosophila TAF of M(r) 80,000, dTAFII80. Sequence analysis reveals that dTAFII80 contains several copies of the WD40 (beta-transducin) repeat. Moreover, dTAFII80 shares extended sequence similarity with an Arabidopsis gene, COP1, which encodes a putative transcription factor that is though to regulate development. We have expressed recombinant dTAFII80 and begun to characterize its interaction with other members of the TFIID complex. Purified recombinant dTAFII80 is unable to bind TBP directly or to interact strongly with the C-terminal domain of dTAFII250 (delta N250). Instead, dTAFII80 is only able to recognize and interact with a higher-order complex containing TBP, delta N250, 110 and 60. These findings suggest the formation of TFIID may require an ordered assembly of the TAFs, some of which bind directly to TBP and others that are tethered to the complex as a result of specific TAF/TAF interactions.