BTB (Broad-Complex, Tramtrack and Bric a brac) /POZ (poxvirus and zinc finger) domain found in Drosophila melanogaster proteins bric-a-brac 1 (BAB1), bric-a-brac 2 (BAB2), modifier of mdg4 (doom), and similar proteins
BAB1 and BAB2 probably act as transcriptional regulators that are required for specification of the tarsal segment and are involved in antenna development. Doom is a product of the Drosophila mod(mdg4) gene. It induces apoptosis and binds to baculovirus inhibitor-of-apoptosis proteins. This subfamily also includes Drosophila melanogaster sex determination protein fruitless (FRU), protein jim lovell (LOV), zinc finger protein chinmo, transcription factor GAGA, transcription factor Ken, and longitudinals lacking proteins (LOLA). FRU probably acts as a transcriptional regulator that plays a role in male courtship behavior and sexual orientation, and enhances male-specific expression of takeout in brain-associated fat body. LOV, also called tyrosine kinase-related (TKR), has a regulatory role during midline cell development. Chinmo is a functional effector of the JAK/STAT pathway that regulates eye development, tumor formation, and stem cell self-renewal in Drosophila. GAGA is a transcriptional activator that functions by regulating chromatin structure. Ken, also termed protein Ken and Barbie, is a transcription factor required for Terminalia development. LOLA proteins are putative transcription factors required for axon growth and guidance in the central and peripheral nervous systems. Proteins in this subfamily contain a BTB domain. The BTB/POZ domain is a common protein-protein interaction motif of about 100 amino acids.