Cotransfer of linked eukaryotic genes and efficient transfer of hypoxanthine phosphoribosyltransferase by DNA-mediated gene transfer.

Abstract

The efficiency of DNA-mediated transfer of the gene (hprt) for hypoxanthine phosphoribosyltransferase (HPRT; IMP:pyrophosphate phosphoribosyltransferase, EC 2.4.2.8) is dependent on the recipient cell used. The hprt gene was transferred into mouse TG8 or Chinese hamster CHTG-49 cells at a high frequency, similar to the frequency of the gene (tk) for thymidine kinase (TK; ATP:thymidine 5''-phosphotransferase, EC 2.7.1.21) transfer into mouse LMTK- cells (i.e., 10-6). The frequency of transfer of hprt into mouse A9 cells was about 2 orders of magnitude less. The identification of efficient recipient cells for hprt transfer permits the use of DNA-mediated transfer as a bioassay for the gene. Cotransfer of the linked tk gene and the gene (galk) for galactokinase (ATP:D-galactose 1-phosphotransferase, EC 2.7.1.6) to LMTK- cells was detected once among 87 tk transferrents. The distance between the tk and galk genes in the Chinese hamster genome may be smaller than was previously thought. Significant differences between chromosome-mediated and DNA-mediated gene transfer were observed with respect to both the size of the transferred functional genetic fragment and the recipient cell specificity.