question: How many DNaseI hypersensitive sites (DHS) mark the murine beta globin locus region?
answer: The expression of genes both from the endogenous locus and from transgenes is strongly influenced by a linked 15-kilobase region of clustered DNaseI hypersensitive sites (HSs) known as the locus control region (LCR) Targeted deletion of 5'HS1 and 5’HS4 of the beta-globin locus Control region reveals additive activity of the sites . The LCR is composed of a series of 5 DNase . sites (5'HSs), that form in the nucleus of erythroid precursors .