Stable oncogenic transformation induced by microcell-mediated gene transfer

Oncogenes have been identified using DNA-mediated transfection, but the size of the transferable and unrearranged DNA, gene rearrangement and amplification which occur during the transfection process limit the use of the techniques. We have evaluated microcell-mediated gene transfer techniques for the transfer and analysis of dominant oncogenes. MNNG-HOS, a transformed human cell line which contained the met oncogene mapping to human chromosome 7 was infected with retroviruses carrying drug resistance markers and used to optimize microcell preparation and transfer. Stable and drug-resistant hybrids containing single human chromosomes as well as the foci of the transformed cells containing the activated met oncogene and intact human chromosomes were obtained. Hybridization analysis with probes (i.e. col1A2, pJ3.11) mapping up to 1 Mb away from met shows that the cells from the individual foci contain different amounts of apparently unrearranged human DNA associated with the oncogene, and the microcell-generated transformants retain more distal markers than those observed in either DNA- or chromosome-mediated transfers. In conjunction with other techniques, microcell fusion should be useful for gene mapping as well as the study of gene function and expression in cell transformation and malignancy.