Expression of human c-raf-1 oncogene proteins in E. coli.

Full length and truncated versions of the human c-raf-1 cDNA were cloned into the inducible E. coli expression vector pJL6. C-raf proteins of 73 kD, 57 kD and 39 kD were produced upon induction. p73 differs from normal p73 c-raf by deletion of the two first N-terminal amino acids and their replacement by 16 amino acids encoded by the vector. The p57 and p39 represent N-terminal deletions which leave the transforming protein kinase domain intact. These proteins could be readily purified from E. coli lysates by immunoprecipitation with raf-specific antisera.