[Fractionation and biosynthesis of rat liver and Zajdela hepatoma nuclear matrix proteins].

A comparative study of the nuclear matrix proteins of rat liver and Zajdela hepatoma cells was performed. The polyacrylamide SDS electrophoretic profile of the hepatoma nuclear matrix proteins differed from those of the liver by the presence of high molecular weight (over 135 KD) bands. Four nuclear matrix fractions were isolated by a subsequent treatment of the preparation with an aqueous solution of EDTA and 0,025 N sodium hydroxide. The bulk of the nuclear matrix proteins of both liver and hepatoma were alkali-soluble. The percentage of the alkali-insoluble residue and of the water-soluble fraction in the Zajdela hepatoma nuclear matrix was 3.5 and 1.7 times that of the liver, respectively. In the course of 60 min incubation of the liver mince or Zajdela hepatoma cells with 14C-Chlorella protein hydrolyzate in vitro the nuclear matrix proteins incorporated by 10-20% more label than did the total nuclear protein, the specific activity of the alkali-insoluble residue being twice higher that of the whole nuclear matrix protein. After 15 min of incubation the label was rather evenly spread along the gel, containing labelled protein bands separated according to their molecular weight. However, after 30 min and especially 60 min of incubation the label markedly prevailed in the high molecular weight proteins.