ABSTRACT
It is shown that heterogeneity of the high-mobility -group proteins (HMG-proteins) in the rat liver does not depend on the animal age, while relative content of certain classes of these proteins and the HMG-proteins H1 histones ratio obeys age specificity. Metabolism of HMG 1 and 2 proteins in animals who have not achieved sexual maturity is low; the intensity of inclusion of labelled predecessors to proteins HMG 14', 17 and 17' decreases in the postnatal ontogenesis. The highest of HMG-proteins is observed in the liver of young (3 months) animals. In old (24 months) rats this process is inhibited. At all the stages of postnatal ontogenesis in the ribosylation intensity of HMG-proteins 14', is higher than that of the other classes of these proteins. The intensity of ribosylation of most fractions of HMG-proteins increases after 12 months.
Subject(s)
Aging/metabolism , High Mobility Group Proteins/metabolism , Acetylation , Animals , Electrophoresis, Polyacrylamide Gel , Histones/metabolism , Rats , Rats, Inbred Strains , Ribose/metabolismABSTRACT
The metabolism of various classes of histones and nonhistone proteins in intact nuclei and in liver chromatin of albino Wistar rats aged 1, 3, 12 and 24 months, was studied. It was shown that in the course of postnatal development the metabolism of nonhistone proteins extracted with 0.14 M NaCl in murine liver is increased. Later in ontogenesis, the incorporation of labeled precursors into proteins HMG 14 and HMG 17 decreases; the specific radioactivity of proteins HMG 1 + 2 is higher in 3- and 24-month-old animals. The intensity of metabolism of nonhistone proteins and histones is higher within the composition of the chromatin complex than in the intact nucleus at all stages of postnatal development. Among other histone proteins, histones H1 are characterized by the highest level specific radioactivity in rats of all age groups.
