マウス腹水肉腫細胞核からの高分子量酸可溶性蛋白質の精製とその性質

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.