Drosophila CP190- and dCTCF-mediated enhancer blocking is augmented by SUMOylation

Background Chromatininsulators shield promoters and chromatindomains from neighboring enhancers or chromatinregions with opposing activities. Insulator-binding proteins and their cofactorsmediate the boundary function. In general, covalent modification of proteins by the small ubiquitin-like modifier (SUMO) is an important mechanism to control the interaction of proteins within complexes.