Figure 4.

Immunoslot analysis of the reaction of antibodies to the individual core histones H2A, H2B, H3, and H4 and preimmune IgG (0) with covalent histone complexes. H1-depleted oligosomes (essentially monosomes, containing small amount of di- and trisomes, see Fig. 1) and core particles were UV laser irradiated with identical doses, and the covalent complexes were purified on CsCl gradients. A series of 5 μg and 2.5 μg of the complexes (measured as DNA) as well as of the control nonirradiated (CON) CsCl-purified samples were loaded on nitrocellulose filters, and the crosslinked histones were detected with immunopurified antibodies. The slots loaded with H1-depleted oligonucleosomes (ONS) or core particles (CPS) are indicated.