The BTB/POZ domain of the regulatory proteins Bric a brac 1 (BAB1) and Bric a brac 2 (BAB2) interacts with the novel Drosophila TAF(II) factor BIP2/dTAF(II)155

The BTB/POZ domain is an evolutionarily conserved protein-protein interacti on domain present in the N-terminal region of numerous transcription factor s involved in development, chromatin remodeling, and human cancers. This do main is involved in homomeric and heteromeric associations with other BTB/P OZ domains. The Drosophila BTB/POZ proteins Brie A brac I (BAB1) and Brie A brac 2 (BAB2) are developmentally regulated transcription factors which ar e involved in pattern formation along the proximo-distal axis of the leg an d antenna, in the morphogenesis of the adult ovaries, and in the control of sexually dimorphic characters. We have identified partners of the BABI pro tein by using the two-hybrid system. The characterization of one of these p roteins, called BIP2 for BAB Interacting Protein 2, is presented. BIP2 is a novel Drosophila TATA-box Protein Associated Factor (TAF(II)), also named dTAF(II)155. We show that the BTB/POZ domains of BABI and BAB2 are sufficie nt to mediate a direct interaction with BIP2/dTAF(II)155. This provides a d irect link between these BTB/POZ transcription factors and the basal transc riptional machinery. We discuss the implications of the interaction between a BTB/POZ domain and a TAF(II) for the molecular mechanisms of transcripti onal control mediated by BTB/POZ transcription factors. (C) 2001 Academic P ress.