Fertility and Germline Transmission of Donor Haplotype Following Germ Cell Transplantation in Immunocompetent Goats

Abstract

Transplantation of spermatogonial stem cells into syngeneic or immunosuppressed recipient mice or rats can result in donor-derived spermatogenesis and fertility. Recently, this approach has been employed to introduce a transgene into the male germline. Germ-cell transplantation in species other than laboratory rodents, if successful, holds great promise as an alternative to the inefficient methods currently available to generate transgenic farm animals that can produce therapeutic proteins in their milk or provide organs for transplantation to humans. To explore whether germ-cell transplantation could result in donor-derived spermatogenesis and fertility in immunocompetent recipient goats, testis cells were transplanted from transgenic donor goats carrying a human alpha-1 antitrypsin expression construct to the testes of sexually immature wild-type recipient goats. After puberty, sperm carrying the donor-derived transgene were detected in the ejaculates of two out of five recipients. Mating of one recipient resulted in 15 offspring, one of which was transgenic for the donor-derived transgene. This is the first report of donor cell-derived sperm production and transmission of the donor haplotype to the next generation after germ-cell transplantation in a nonrodent species. Furthermore, these results indicate that successful germ-cell transplantation is feasible between immunocompetent, unrelated animals. In the future, transplantation of genetically modified germ cells may provide a more efficient alternative for production of transgenic domestic animals.

Efficient nonmeiotic allele introgression in livestock using custom endonucleases

“…Pigs edited to disrupt the DAZL gene can serve as a model for studying the restoration of human fertility by germ cell transplantation or for producing genetically modified offspring by transfer of genetically modified germline stem cells, as has been demonstrated in pigs (45), goats (46), and rodents (47,48). Gene-edited alleles of APC also could provide a size-relevant model of colon cancer for preclinical evaluation of therapeutics, surgical intervention, or detection modalities.…”

Male germ cell transplantation in livestock

“…Successful germ cell transplantation in rodents, and perhaps cattle, requires that recipient animals are either closely related to the donor or immunosuppressed (Izadyar et al 2003a;Kanatsu-Shinohara et al 2003a;Zhang et al 2003), whereas germ cell transplantation in pigs and goats was also successful between unrelated individuals (Honaramooz et al 2002b(Honaramooz et al , 2003a(Honaramooz et al , 2003b. The results obtained from this latter research indicate that successful germ cell transplantation is feasible between immunocompetent, unrelated animals and that this process can produce live offspring in non-rodent species.…”

“…The germ cell transfer technique used in pigs and goats is readily adapted to cattle (Honaramooz et al 2002b(Honaramooz et al , 2003a(Honaramooz et al , 2003bIzadyar et al 2003a;Joerg et al 2003;Hill et al 2005) and the approach in cattle is schematically summarised in Fig. 1.…”

“…Transgenic animals can be produced via the transfer of transgenic donor germ cells (Honaramooz et al 2003a). The advantage over inducing transgenesis using nuclear transfer technology is the reduced interval to producing 'founder' transgenic sires, because the recipient animals will be capable of mating and sperm production in a much shorter time than animals generated by nuclear transfer.…”

“…Transplanted germ cells are able to produce 'normal' sperm, as demonstrated by fertilisation in vivo and in vitro (Brinster and Avarbock 1994;Goossens et al 2003;Honaramooz et al 2003a). Time to sperm production can also be markedly accelerated because even mouse primordial germ cells transferred to a post-natal testis were shown to support spermatogenesis (Chuma et al 2005).…”