On the de novo formation of compact oligonucleosomes at high ionic strength. Evidence for nucleosomal sliding in high salt

Abstract

Histone H 1-depleted chromatin made from acid extracted, intact nuclei was exposed to various ionic strengths. NaCl concentrations above 0.3 M sufficed to generate novel oligonucleosomes formerly characterized as "compact oligomers" and "spacerless dinucleosomes". Such particles could not be identified within H 1-depleted nuclei or chromatin at low ionic strengths. Their formation, proceeding within days at 0 degrees C, was accelerated by increasing ionic strengths. The data was discussed in terms of a salt-induced motion of nucleosomal core particles along the DNA to form compact oligomers.