Genome-wide distribution of proteins Pita, ZIPIC, Zw5 in Drosophila embryos

According to recent models, as yet poorly studied architectural proteins appear to be required for local regulation of enhancer–promoter interactions, as well as for global chromosome organization. Transcription factors ZIPIC, Pita, and Zw5 belong to the class of chromatin insulator proteins and preferentially bind to promoters near the TSS. They are structurally similar in containing the N-terminal zinc finger-associated domain (ZAD) and different numbers of C2H2-type zinc fingers at the C-terminus. We have shown that the ZAD domains of ZIPIC, Pita, and Zw5 usually form homodimers. In Drosophila transgenic lines, these proteins can support long-distance interaction between GAL4 activator and the reporter gene promoter. However, no functional interaction between binding sites for different proteins has been revealed, suggesting that such interactions are highly specific. ZIPIC facilitates long-distance stimulation of reporter gene by GAL4 activator in yeast. Thus, ZAD-containing zinc-finger proteins probably belong to the class of architectural proteins. Overall design: ChIP-Seq for Pita, ZIPIC, Zw5 proteins from Drosophila embryos