Antibodies to the evolutionarily conserved amino-terminal region of the v-myb-encoded protein detect the c-myb protein in widely divergent metazoan species.

Antibodies directed against a bacterial fusion protein that contains the domain encoded by the highly evolutionarily conserved 5' one-third of the v-myb oncogene of avian myeloblastosis virus (AMV) detect the protein products of various members of the myb gene family. Immunoprecipitation or immunoblot analyses with these antibodies yielded the following information. First, the products of the v-myb oncogenes of AMV (p48v-myb) and of E26 virus (p135gag-myb-ets) contain this highly conserved amino acid sequence, as previously hypothesized. Second, p75c-myb, the product of the chicken c-myb protooncogene, also contains this protein domain. Third, these antibodies have identified the products of the human, murine, and Drosophila c-myb genes, which were all found to be nuclear proteins of Mr 75,000-80,000. The human c-myb protein product is present in immature cells of the erythroid, myeloid, and lymphoid lineages.