Role of histones H1 and H3 in the maintenance of chromatin in a compact conformation

Abstract

Chromatin polynucleosomes have been digested with trypsin immobilized on collagen membranes. This method allows the mild removal of the most accessible histone fragments simply by dipping the enzymatic membrane into the chromatin solution, without modification of its ionic and chemical composition. These results demonstrate that the removal of H1 does not affect the higher-order structure of chromatin and that only the elimination of the terminal regions of H3 leads to the unfolding of H1-depleted fibres. This observation suggests that structural changes reported in many previous works were not due to only the removal of H1 but to a concomitant unbinding from DNA of the N-terminal domain of H3.