Electrophoretic separation of a class of nucleosomes enriched in HMG 14 and 17 and actively transcribed globin genes.

Monomer nucleosomes from chick erythrocytes can be fractionated according to their electrophoretic mobility in (comparatively) high salt acrylamide gels. We show that the fractionation is based predominantly on differences in charge. The monomer heterogeneity persists even when the nucleosomes are trimmed down to 145 bp with Exo III or when H1 and H5 are removed. The slowest migrating monomers are associated with HMG 14 and 17; however, we do not believe that these proteins are entirely responsible for the altered mobility since the nucleosome heterogeneity persists even after removal of HMG 14 and 17. The DNA associated with the HMG 14 and 17 containing nucleosomes is shown to be enriched in actively transcribed globin sequences.