Purification and properties of a high molecular weight acid soluble nuclear protein from mouse ascites sarcoma cells

A high molecular weight acid soluble nuclear protein (HAN-1) was isolated in a electrophoretically homogeneous state from mouse ascites sarcoma cells (SR-C3H cells) by the exclusion chromatography in Sephacryl S-200 and the DEAE-Sephadex chromatography of the nuclear 0.2M H(2)SO(4) extract. The content of HAN-1 in SR-C3H nuclei was about 4.3% per total histone, the highest among the cell types tested. The molecular weight of HAN-1 was estimated to be 125,000 by SDS-polyacrylamide gel electrophoresis. The amino acid composition of HAN-1 was rich in glutamic acid, alanine, lysine and aspartic acid, the acidic/basic amino acid ratio 1.8. The in vitro RNA synthesizing activity of SR-C3H cell RNA polymerases Ⅰ and Ⅱ on a naked DNA template was differentially affected by HAN-1; the reaction with polymerase I was inhibited and that with polymerase Ⅱ stimulated.