Testis-Mediated Gene Transfer (TMGT) in Mice: Effects of Repeated DNA Injections on the Efficiency of Gene Delivery and Expression
Masahiro Sato and Shingo Nakamura
We have attempted to establish a new method, “testis-mediated gene transfer, TMGT,” based upon gene transfer via direct introduction of exogenous plasmid DNA into a testis as an alternative to microinjectionmediated transgenesis. Relatively high gene delivery into F0 offspring was achieved when males were singly injected with DNA/liposome complex and subsequently mated to superovulated females. However, the number of DNA in those offspring was below 1 copy per diploid cell. In an attempt to increase the copy number of exogenous DNA in offspring, repeated injections (singly, 3 or 6 times 3 days apart) into adult murine testes were performed. A high rate of gene transfer was achieved with multiple injections, although introduction of high numbers of copies (more than 1 copy per diploid cell) of DNA failed. Expression of transgene-derived mRNA was observed, although its strength appeared still to be very low. These findings suggest that repeated injections are not critical to introduction of high numbers of copies of DNA into ova in this TMGT system.