Immortalization of multiple cell types from transgenic mice using a transgene containing the vimentin promoter and a conditional oncogene.

Differentiated clonal cell lines were obtained from transgenic mice carrying a recombinant gene composed of DNA coding for a temperature-sensitive mutant of the simian virus large T antigen under the control of regulatory elements of the human vimentin gene. In response to mitogenic factors the vimentin promoter is activated in the presence of serum in almost all cultured cells independently of their origin. The expression of the T antigen could be controlled both at the level of transcription since the vimentin promoter is growth-regulated and at the level of the protein structure through the temperature stability of the T antigen. Indeed, the switch-off of the oncogene protein is obtained by serum deprivation of the culture and achieved with enhancement of the growth temperature. From transgenic mice several types of clonal differentiated cell lines were established and characterized including melanocytes, macrophages, mesangial, muscle, and endothelial cells. Melanocytes displayed melanin while endothelial cells from brain and heart expressed the related factor VIII and low density lipoprotein absorption capacities. Mesangial cells from kidney exhibited numerous desmosomes. Typical markers of macrophages from bone marrow were observed while skeletal muscle cells fused and contracted.