Mutational Activation of pp60c-src Leads to a Tumorigenic Phenotype in a Preneoplastic Syrian Hamster Embryo Cell Line

摘要: Previous studies indicated that overexpression of wild-type avian c-src cannot induce neoplastic transformation NIH 3T3 cells. In this study, we isolated and characterized novel spontaneously derived transforming mutants pp60c- src from a Syrian hamster embryo-derived cell line, 10W, transfected with the c- gene. Seventeen independently 10W clones were injected into athymic nude mice. After latency period, tumors eventually arose established in culture. The tumorigenic phenotype was always accompanied by presence DNA functional expression . However, most tumor-derived lines expressed an electrophoretically altered form , suggesting mutations src. Consistent hypothesis, DNAs lines, but not parental morphologically transformed cells focus-forming assay. We detail three lines: 4AT, 4BT, E2T. Two these contained within exogenous coding region. Line 4AT has internal repeat 29 amino acids immediately following Gln-513, which disrupts spacing between end kinase domain Tyr-527, negative regulatory site 4BT 5-bp deletion Phe-520, results loss Tyr-527. sequence region third E2T, completely wild type. Cyanogen bromide cleavage analyses showed regulation is phosphorylated, Tyr-416, vitro autophosphorylation, phosphorylated. line Tyr-527 Tyr-416 phosphorylated to lesser extent. Additionally, two proteins indicate activation p85 cortactin p120cas, are at least six although extent These suggest dephosphorylation phosphorylation correlate respectively. high levels combination partial protein as appear be involved process, rather than mutation.