TRANSFORMATION OF CHICKEN BONE-MARROW CELLS BY THE V-SKI ONCOGENE

The effect of the v-ski oncogene on the transformation of chicken hematopoietic cells was examined. In initial experiments viruses encoding the v-ski oncoprotein did not transform chicken bone marrow cells. However, whereas viruses encoding the ts-v-sea oncoprotein transform solely erythroid cells, viruses encoding both the v-ski and the ts-v-sea oncogenes were found capable of transforming myeloid cells from the monocytic and/or granulocytic lineages in addition to erythroid cells. Analysis of cell clones transformed by the v-ski/ts-v-sea virus identified one clone that no longer expressed the v-sea protein, indicating that this protein was necessary for the initiation but not the maintenance of transformation. Subsequent experiments testing the effects of various growth factors on transformation of bone marrow cells by the v-ski oncogene product alone identified the avian c-kit ligand (stem cell factor; SCF) as being able to co-operate with the v-ski protein to cause transformation of chicken hematopoietic cells of both myeloid and erythroid lineages.