NONHISTONE PROTEIN REORGANIZATION IN NORMAL AND HEPATOMA-CELLS

Previously we described (Dong et al., 1990) a nuclear protein (mol, wt . 112 kD) which is expressed abundantly in hepatoma cells and also in hepatocyte cells committed to carcinogenesis. In this report, we furth er characterize its chemical properties and cellular localization in n ormal and hepatoma cells. 112 kD hepatoma-associate nonhistone protein is not a cytokeratin-related protein as described by Fukuda et al. (1 991). Protein purification experiments revealed that 112 kD protein is a dimer of 56 kD polypeptide present in normal rat liver nuclei. Intr anuclear distribution pattern indicated that 112 kD nonhistone protein localizes exclusively in hepatoma nuclear matrix. The data from this study suggest that dimerization of 56 kD nonhistone protein is involve d in nuclear matrix reorganization during neoplastic transformation.