Plasma membrane proteins exposed on the outer surface of control and Rous sarcoma virus (RSV)-transformed baby hamster kidney (BHK) fibroblasts were selectively labelled with the probe trinitrobenzene sulphonic acid. Labelled proteins were solubilized with detergent and purified by affinity chromatography on insoluble anti-probe antibodies. Analysis in sodium dodecylsulphate polyacrylamide gel electrophoresis showed that at the surface control cells expose seven major groups of components, peaks A, B, C, D, E, F, and s, with approximate molecular weights of 200, 100, 75, 50, 45, 40, 23 K D. The same number of peaks was observed in RSV-transformed fibroblasts. However, in transformed cells one peak (C) was shifted to a backward position (C′) showing a difference in relative mobility of 4%. Comparison of TNP-labelled cell surface proteins after further separation on SDS-hydroxylapatite chromatography showed that the shift of peak C to C′ in transformed cells was due to the presence of an extra component of molecular weight between 80-100 K D undetectable in control cells. The shift of peak C to C′ was independent of cell growth; moreover, in fibroblasts transformed by a temperature-sensitive mutant of the RSV, it was observed at the permissive but not at the restrictive temperature, showing correlation with the expression of the transforming gene.
ASJC Scopus subject areas
- Cell Biology