CORE HISTONE HYPERACETYLATION CO-MAPS WITH GENERALIZED DNASE-I SENSITIVITY IN THE CHICKEN BETA-GLOBIN CHROMOSOMAL DOMAIN

The distribution of core histone acetylation across the chicken beta-g lobin locus has been mapped in 15 day chicken embryo erythrocytes by i mmunoprecipitation of mononucleosomes with an antibody recognizing ace tylated histones, followed by hybridization probing at several points in the locus. A continuum of acetylation was observed, covering both g enes and intergenic regions. Using the same probes, the generalized se nsitivity to DNase I was mapped by monitoring the disappearance of int act genomic restriction fragments from Southern transfers. Close corre spondence between the 33 kb of sensitive chromatin and the extent of a cetylation indicates that one role of the modification could be the ge neration and/or maintenance of the open conformation. The precision of acetylation mapping makes it a possible approach to the definition of chromosomal domain boundaries.