CELLULAR PROTEINS IN ONCOGENE TRANSFORMED RAT LIVER EPITHELIAL CELLS

点击翻译按钮获取中文摘要

In order to identify the cellular proteins that are associated with neoplastic development, we have used an in vitro transforming system consisting of helper-dependent retroviruses containing either v-raf or v-raf/v-myc as the transforming agents and rat liver epithelial (RLE) cell line as the reporter cell. Both v-raf (3611) and v-raf/v-myc (J2) viruses were efficient in vitro transforming agents of the RLE cells and the infected cells formed tumors upon transplantation in nude mice. Neither the uninfected nor helper virus-infected RLE cells formed tumors in nude mice. Cellular protein patterns in normal RLE cells, helper-infected (RLE-H), 3611 (RLE-3611T)- and J2 (RLE-J2)-transformed RLE cells have been analyzed by two-dimensional polyacrylamide gel electrophoresis (2D-PAGE). Comparison of the autoradiograms from the RLE-H, RLE-3611T and RLE-J2, nine proteins which are either suppressed or induced were selected for closer study and purification. Polypeptides 1 - 4 (Mr/pI) (1. 145/5.9-7.2; 2. 130/6.5-7.5; 3. 100/4.0; 4. 30/6.0) were found be present in negligible amounts in the tumorigenic cells from both autoradiograms and silver-stained 2-dimensional polyacrylamide gels and polypeptides 5 - 9 (Mr/pI) (5. 27/5.0; 6. 26/4.9; 7. 25/4.9; 8. 25/5.2; 9. 27/6.6) were found to be present in negligible amounts in the nontumorigenic RLE-H cells. Protein 1 appears to be associated with both soluble and membrane fractions; polypeptides 2, 3, 4, 8 and 9 appear to be associated with membrane and polypeptides 5, 6 and 7 appear in the cytosolic fraction.