Release of a globin gene enriched chromatin fraction from chicken erythrocyte nuclei following DNase II digestion.

Mild digestion of chicken erythrocyte nuclei with deoxyribonuclease II results in the release of a chromatin fraction which is 4- to 13-fold enriched for the globin coding sequences when compared to total chicken DNA. The remaining nuclear pellet is depleted in these sequences. A maximum of 25% of the globin genes have been recovered in the released fraction. The addition of 5 mM sodium butyrate to the digestion buffer is required to obtain reproducible globin gene enrichment. The released fraction contains equimolar amounts of the four core histones and a subset of the nonhistone chromosomal proteins. The globin genes are released as large chromatin fragments which exceed the 1.6 kilobase size of the transcribed portion of the gene.