The interaction of H1 histone with nucleosome core

The structural changes caused by H1 histone depletion of calf thymus chromatin or nucleosome monomer were studied by using the criterion of accessibility to micrococcal nuclease. When H1 histone was depleted from monomer, the DNS structure unfolded and became sensitive to the nuclease at a particular site on the nucleosome core, 105 base pairs from a chain terminus of core DNA. In reconstitution experiments with chromatin, this sensitive site on the core could be protected from the attack of the nuclease only when H1 histone was present. These results indicate that H1 histone interacts not only with the nucleosome linker region, but also with the core particle.