Transcriptional activator that functions by regulating chromatin structure. Overcomes the repressive effects of chromatin by promoting the open chromatin conformation in promoter gene regions, thereby allowing access to other transcription factors. Binds to DNA Polycomb response elements (PREs) at the bithorax complex and to the proximal region of the engrailed promoter, and positively regulates transcription of many genes including homeotic ones. Binds to the DNA sequence (GA)n, with optimal binding to the pentamer 5'-GAGAG-3'. Binds DNA as an oligomer. May also act as a transcriptional repressor, maintaining the repressed state of genes including lolal, and down-regulating its own transcription. Required for dosage compensation in males and may be involved in oogenesis. Also has a role in nuclear division. Interacts with Bin1, lolal, corto, ttk and ph-p (PubMed:11256608, PubMed:12384587, PubMed:12834867, PubMed:12771214). Interacts with FACT subunits Ssrp and dre4/SPT16 (PubMed:12815073). Interacts with E(bx) (PubMed:11583616). Upon ecdysone stimulation, interacts with Nup98 (PubMed:28366641). Expressed in the central nervous system throughout development. Expressed ubiquitously during embryogenesis with higher levels found from 9-12 hours after egg laying. Low levels are found in larvae and adults. The N-terminal BTB domain mediates protein oligomerization. The C-terminal glutamine-rich region is required for transcriptional activation activity. The N-terminus is blocked.