TRANSFORMATION OF FDC-P1 CELLS TO IL-3 INDEPENDENCE BY A RECOMBINANT MURINE RETROVIRUS CONTAINING V-ERB-B

The oncogene v-erb-B has been shown to transform pre-B lymphocytes and early erythroid precursor cells and has been implicated in leukemogen esis. We have examined the effect of this oncogene on the growth of a murine myeloid interleukin-3 (IL-3)-dependent cell line, FDC-P1. FDC-P 1 cells were infected with a recombinant murine retrovirus containing v-erb-B. As a result, clonal IL-3-independent cell lines (FI-v-erb-B) were generated with a high level of v-erb-B expression and an altered morphology compared to parental FDC-P1 cells. The FI-v-erb-B cells wer e tumorigenic and did not express or secrete IL-3, suggesting the acqu isition of IL-3 independence by a non-autocrine mechanism. In addition to the formation of myeloid colonies, FI-v-erb-B cells, when grown in semi-solid medium with exogenous IL-3, erythropoietin (Epo), or IL-3 plus Epo, could also form erythroid and mixed-erythroid colonies. By c ontrast, parental FDC-P1 cells formed only myeloid colonies under the same conditions. Our results indicate that v-erb-B abrogates growth fa ctor dependence in these cells and may cause Lineage modulation by act ing to allow the induction of erythroid differentiation in FI-v-erb-B cells.