ABSTRACT
Spermatogonial stem cells (SSCs) transmit genetic information to the next progeny in males. Thus, SSCs are a potential target for germline modifications to generate transgenic animals. In this study, we report a technique for the generation of transgenic rats by in vivo manipulation of SSCs with a high success rate. SSCs in juvenile rats were transduced in vivo with high titers of lentivirus harboring enhanced green fluorescent protein and mated with wild-type females to create founder rats. These founder rats expressed the transgene and passed on the transgene with an overall success rate of 50.0%. Subsequent generations of progeny from the founder rats both expressed and passed on the transgene. Thus, direct modification of SSCs in juvenile rats is an effective means of generating transgenic rats through the male germline. This technology could be adapted to larger animals, in which existing methods for gene modification are inadequate or inapplicable, resulting in the generation of transgenic animals in a variety of species.
ABSTRACT
Spermatogonial stem cells (SSCs) transmit genetic information to the next progeny in males. Thus, SSCs are a potential target for germline modifications to generate transgenic animals. In this study, we report a technique for the generation of transgenic rats by in vivo manipulation of SSCs with a high success rate. SSCs in juvenile rats were transduced in vivo with high titers of lentivirus harboring enhanced green fluorescent protein and mated with wild-type females to create founder rats. These founder rats expressed the transgene and passed on the transgene with an overall success rate of 50.0%. Subsequent generations of progeny from the founder rats both expressed and passed on the transgene. Thus, direct modification of SSCs in juvenile rats is an effective means of generating transgenic rats through the male germline. This technology could be adapted to larger animals, in which existing methods for gene modification are inadequate or inapplicable, resulting in the generation of transgenic animals in a variety of species.
Subject(s)
Animals , Male , Rats , Green Fluorescent Proteins , Lentivirus , Rats, Transgenic , Spermatogonia/metabolismABSTRACT
Spermatogonial stem cells (SSCs) are essential for spermatogenesis throughout the lifespan of the male. However, the rarity of SSCs has raised the need for an efficient selection method, but little is known about culture conditions that stimulate monkey SSC proliferation in vitro. In this study, we report the development of effective enrichment techniques and in vitro culturing of germ cells from pre-pubertal monkey testes. Testis cells were analyzed by fluorescence-activated cell sorting techniques and were transplanted into the testes of nude mice to characterize SSCs. Thy-1-positive cells showed a higher number of colonies than the unselected control after xenotransplantation. Extensive colonization of monkey cells in the mouse testes indicated the presence of highly enriched populations of SSCs in the Thy-1-positive sorted cells. Furthermore, monkey testis cells were enriched by differential plating using extracellular matrix, laminin, and gelatin, and then cultured under various conditions. Isolation of monkey testicular germ cells by differential plating increased germ cell purity by 2.7-fold, following the combinational isolation method using gelatin and laminin. These enriched germ cells actively proliferated under culture conditions involving StemPro medium supplemented with bFGF, GDNF, LIF, and EGF at 37 ℃. These results suggest that the enrichment and in vitro culture method proposed in the present study for harvesting a large number of functionally active monkey SSCs can be applied as the basis for efficient in vitro expansion of human SSCs.