The Methylation of the Histones of Rat Liver Nucleiin vitro

Abstract

Rat liver nuclei isolated with Triton X-100, or by the method of Chauveau, are able to incorporate the methyl group of S-adenosyl-methionine into histones, where it becomes the methyl group of N-methyllysine. The CH3-group of methionine is also incorporated, but to a much lesser extent. The process is independent of an energy supply, requires Mg-ions and shows optimum at about pH 9. Incorporation is independent of histone turnover. After fractionation of the methylated histones according to Johns, the highest incorporation is found in the F3-histone fraction followed by the F2b, F2a, and F1. The enzyme activity is found almost exclusively on the nucleolochromosomal part of the nuclei.