Highly glycosylated PDGF-like molecule secreted by simian sarcoma virus-transformed cells

Antiserum to human platelet-derived growth factor (PDGF) recognized a simian sarcoma virus transformation-specific glycopeptide, now termed gp200sis, thereby establishing an immunological relationship between PDGF and this highly glycosylated molecule. The same antibodies as well as an antiserum against SSV-NP cells reacted with isolated gp200sis after immunoprecipitation, SDS-PAGE, and electroelution. In analogy to PDGF, the gp200sis protein backbone is shown here to consist of disulfide-linked polypeptide chains. On SDS-PAGE under nonreducing conditions, the deglycosylated molecule migrated as two dimers with molecular weights of 26 and 28 kDa, respectively. Preliminary functional studies indicate that SSV nonproducer cells secrete high-molecular-weight mitogens (greater than 150 kDa) that are specific for SSV-induced transformation. We suggest that gp200sis acts as a PDGF-like growth factor.