Abstract
Nuclear proteins of rat liver and rat ascites hepatoma were fractionated by extraction in solutions of different salt concentration and analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis. The difference between the electrophorograms of the different fractions of nuclear proteins isolated from liver and from hepatoma was found in the bands which have the same electrophoretic mobility as the main proteins of informofers and are extracted from nuclei at salt concentrations which extract informofers. These changes in the electrophoretic patterns of proteins with the solubility and mobility of the proteins of informofers could be related to the defective processing of heterogeneous nuclear RNA in the hepatoma. In addition the identity of electrophorograms of nuclear proteins isolated from liver and from hepatoma and the identity of most bands in the electrophorrgrams of nuclear proteins which are soluble in 0.35 M NaCl and chromosomal proteins which are not soluble at this salt concentration support the notion that these nonhistone nuclear proteins which can be identified as the major bands in electrophorograms of chromosomal proteins are not the specific regulators of gene expression.