The DNase I generated disomal series is coherent to 16N. Implications for coiling models of chromatin structure

Davis SJ, Burgoyne LA. (1987), FEBS Lett. 226, 88-90

Abstract

The disomal series generated by the digestion of chromatin with DNase I has been followed to its highest orders using Klenow end-labelling and field-inversion gel electrophoresis to maximise the resolution of large DNA fragments. The series is coherent to the 16N level and as such is incompatible with the most structurally acceptable coiling models. We propose that this is evidence for the general unsuitability of coiling models and is support for the existence of simple ‘back-to-back’ double-stranded structures within chromatin.

Key figure

Standard and field-inversion gel electrophoresis of chromatin fragments from chicken erythrocytes permeabilised and probed with ferritin-DNase I. The DNA was end-labelled with [³²P]dATP using the Klenow fragment of polymerase I. Autoradiographs of the gels were analysed by computer-assisted densitometry.