The two activation domains of the CCAAT-binding factor CBF interact with the dTAFII110 component of the Drosophila TFIID complex

• Published in: Biochemical journal 1998-04, Vol.331 ( Pt 1) (1), p.291-297
• Main Authors: Coustry, F, Sinha, S, Maity, S N, Crombrugghe, B
• Format: Article
• Language: English
• Subjects: Animals; Binding Sites - genetics; Core Binding Factors; DNA-Binding Proteins - genetics; DNA-Binding Proteins - metabolism; Drosophila; Drosophila Proteins; Neoplasm Proteins; Protein Binding; TATA-Binding Protein Associated Factors; Transcription Factor TFIID; Transcription Factors - genetics; Transcription Factors - metabolism; Transcription Factors, TFII - genetics; Transcription Factors, TFII - metabolism
• ISSN: 0264-6021; 1470-8728
• DOI: 10.1042/bj3310291

The CCAAT-binding factor CBF is a heterotrimeric transcription factor that specifically binds to CCAAT sequences in many eukaryotic genes. Previous studies have shown that CBF contains two transcription activation domains: a glutamine-rich, serine-threonine-rich domain present in the CBF-B subunit and a glutamine-rich domain in the CBF-C subunit. In this study, by using a series of deletion mutations of CBF-B and CBF-C in transcription assay in vitro, we further delineated smaller segments in these domains that were sufficient to support transcriptional activation by CBF. To test whether transcription activation by CBF requires co-activators, we examined the interaction between CBF and dTAF110, a component of the Drosophila TFIID complex. Recent work has demonstrated that glutamine-rich domains of the Sp1 transcription factor interact with dTAF110 and that this interaction has an important role in mediating transcription activation. Here we first demonstrate in a direct interaction assay in vitro that CBF binds dTAF110. By using a yeast two-hybrid system we show that both of the transcription activation domains of CBF interact with dTAF110. A deletion analysis suggests that a segment of CBF-B needed for transcription activation is also involved in interaction with dTAF110. In CBF-C the C-terminal portion of the molecule seems to be needed for these two activities. Our results suggest that TAF110 might represent one of the co-activators that mediate transcriptional activation by CBF.