ABSTRACT
The dbl oncogene was initially isolated from a human diffuse B-cell lymphoma. Antisera from mice bearing tumors induced by this oncogene specifically detected a protein of about 66 kDa (p66) in dbl transformants. dbl cDNA-selected poly(A)+ RNA isolated from a transfectant clone expressing p66 directed the in vitro synthesis of this protein, establishing that it is encoded by dbl. Subcellular localization studies revealed that p66 is a cytoplasmic protein distributed between cytosol and crude membrane fractions. Moreover, p66 was shown to be a phosphoprotein, with phosphorylation specific to serine residues. Our characterization of the dbl-encoded protein appears to distinguish this transforming gene product from those of other known oncogenes.
