A previous study has revealed that undifferentiated progenitor type-A spermatogonia originating from a spermatogenic stem cell proliferate and extend horizontally onto the basement membrane. Serial distribution along the tubules of sper-matogenic stem cells has recently been reported in the testes of transgenic mice carrying a lacZ reporter driven by a specific promoter of a mouse retrotransposon gene that is specifically expressed in the spermatogenic stem cell. Judging from these data, we believe that our EP transfection method is sufficiently efficient for introducing a foreign gene even into spermatogenic stem cells, and also that the transgene can be transmitted to the progenitor spermat-ogenic cells as development proceeds. ventolin 100 mcg
We have not examined whether the transgene was integrated into chromosomal DNA; however, it probably was since apparently stable expression of the transfected DNA was detected in stem germ cells and in their daughter cells. Further improvement of this method, in particular by raising the transfection efficiency into self-renewal stem cells, should allow us to perform in vivo functional analyses of a foreign gene during spermatogenesis in living testes, and ultimately this method could provide us with a new tool for producing transgenic animals.