Erythroproliferation in vitro can be induced by abl, fes, src, ras, bas, raf, raf/myc, erb B and cbl oncogenes but not by myc, myb and fos.

To assess the erythroproliferative effects of a variety of retroviruses in vitro, hemopoietic precursors were incubated with the viruses then plated in methylcellulose. Only replication defective transforming viruses were active in this assay and produced colonies of erythroid cells. The effective transforming viruses were: Friend virus and viruses containing the abl, fes, src, Ha-ras, Ki-ras, bas, raf, raf/myc, erb B and cbl oncogenes. Replication competent viruses and those bearing the myc, myb and fos oncogenes were unable to initiate colony formation. Significant differences were observed in the colonies induced by several of the transforming genes based on (i) colony size, (ii) morphology, (iii) time course of development and (iv) sensitivity to erythropoietin. The oncogene-expressing retroviruses appeared to have the same target cell, which may be less differentiated erythroid precursor than the target cell for Friend virus.