Identification of transformation-specific proteins synthesized in cryptovirogenic mammalian cells.

The cryptovirogenic PR-RSH-19 (H-19) hamster cell line, derived originally from a tumour induced by the virus rescued from XC cells by transfection, was studied. The pp60v-src protein was detected by immunoprecipitation with sera from tumour-bearing rabbits (TBR sera) from lysates of H-19 cells. A closely related protein p60 was precipitated by antiserum obtained from hamsters with tumours induced by H-19 cells. The pp60v-src of H-19 cells possesses an associated kinase activity. These results are consistent with the notion that the detected pp60v-src protein is a product of the cryptic sequences in H-19 cells.