Mapping long-range chromatin organization within the chicken α-globin gene domain using oligonucleotide DNA arrays

We have analyzed the organization of the chicken α-globin gene domain using DNA miniarrays and have found two novel chromatin loop attachment regions. We have found a 40-kb loop domain that includes all the α-globin genes in cells of erythroid origin. One of the domain borders colocalizes almost exactly with a strong MAR element and with a block of enhancer-blocking elements found earlier at the upstream end of the α-globin gene domain. The domain structure was found to be different in a lymphoid cell line DT40. We propose to use the technique of DNA arrays to map the nuclear matrix attachment sites that define the borders of chromosome loop domains. The technique of DNA arrays permits a large number of DNA sequences to be immobilized on a glass or nylon matrix. This may prove useful for mapping chromatin loop positions within the human genome by using a pool of chromatin loop attachment regions as a probe in a hybridization with a DNA chip containing a specific DNA region.