1999 Volume 45 Issue 2 Pages 111-118
A transgenic pig carrying MMTV/v-Ha-ras was produced by microinjection of DNA into pronuclear stage embryos. Reproductive technologies, such as superovulation, insemination methods and synchronization of recipients were also investigated to establish the efficient systems to obtain pronuclear stage embryos and transgenic pigs aiming at improving efficiency of the protocol for producing transgenic pigs. Integration of the transgene was detected by Southern hybridization analysis in one female among 29 piglets which had been born after transfer of 195 DNA-injected embryos to 8 recipients. Expression of the transgene was detected by RT-PCR in 8 of 17 organs of the founder transgenic pig examined. The transgenic pig transmitted the transgene to 42.3% of 26 offspring. However, development of tumour was not found either in the founder or its progeny during the observation period for 30 and 1-8 months, respectively. The average number of ova collected from donors superovulated with 1500 IU eCG was significantly higher than the number collected from gilts which were superovulated with 1000 IU (26.3 vs 6.8, P<0.05). Donors served by artificial insemination yielded nearly the same number of embryos per head as those mated naturally (14.8 vs 16.1 ). Recipients of which the estrus was synchronized through administration of either 1500 or 750 IU eCG gave rise to pregnancies (5/5 vs 3/4). These data indicate that transgenic pigs carrying activated oncogene can be produced, though induction of the developmental disorders is yet to be investigated.
