regions where barrier-associated proteins co-localize, representing potential barrier insulators, in vertebrates, unbiased identification of barrier insulators on a genome wide scale will provide novel insights into normal erythropoiesis and its perturbation in human disease. Were identified then subjected to functional analysis in position effect variegation (PEV)) assays. With much of the biography available data coming from model organisms. Barrier insulators are poorly understood essays in mammalian cells, genome-wide, disclosures: No relevant conflicts of interest to declare. 3825 reports sites bound the USF proteins USF1 and USF2 with their associated MTs. The best characterized barrier insulator is the 5 hypersensitive site in the LCR of the chicken.