Specific expression of the human cellular fps/fes-encoded protein NCP92 in normal and leukemic myeloid cells.

We have found that both an antibody directed against a synthetic peptide representing an amino acid sequence of the conserved kinase domain of transforming protein P140 of Fujinami sarcoma virus and a regressing tumor antiserum recognized the products of the c-fps/fes genes of both avian and mammalian cells. The anti-peptide antibody also recognized a 94-kilodalton protein that was related to but distinct from the c-fps/fes product in structure and in tissue distribution. A 92-kilodalton protein, NCP92, was found to be the mammalian counterpart of the previously identified avian c-fps/fes protein NCP98 by its structural similarity to NCP98, its associated tyrosine kinase activity, and its similar tissue distribution. The highest levels of NCP92 were found in tissue macrophages and in bone marrow. In bone marrow NCP92 expression was restricted to cells of the monocyte/macrophage and granulocyte lineages. That the expression of NCP92 is limited to these cell types was confirmed by the analysis of murine and human hematopoietic tumors representing different cell lineages: NCP92 was positive in leukemic cells of granulocytic and monocytic origin but not in B-lymphocytic, T-lymphocytic, or erythroid tumor cells. The expression of NCP92 seems to be related to the capacity of myeloid cells to differentiate and to respond to certain colony-stimulating factors.