Cotransfer of thymidine kinase and galactokinase genes by chromosome-mediated gene transfer.

Abstract

The Chinese hamster genes for thymidine kinase (ATP:thymidine 5''-phosphotransferase, EC 2.7.1.75) and galactokinase (ATP:D-galactose 1-phosphotransferase, EC 2.7.1.6) were co-transferred to mouse cells by chromosome-mediated gene transfer. Hamster metaphase chromosomes were incubated with mouse B82 cells and 22 independent colonies were isolated in a selective medium. All of the 12 colonies analyzed expressed the donor form of thymidine kinase; the hamster form of galactokinase was also expressed in 2 of these colonies, indicating co-transfer with a frequency of about 20%. There was coordinate loss of both transferred genes from each colony when selection was applied for the loss of thymidine kinase alone. Comparison of the regional localization of these 2 linked genes with the frequency of co-transfer suggests that the transgenome is probably not larger than about 0.25% of the donor genome.