Production of transgenic mice expressing tumor virus A under ovarian‑specific promoter 1 control using testis‑mediated gene transfer.

The aim of the present study was to produce transgenic mice expressing tumor virus A (TVA) in the ovary under ovarian specific promoter 1 (OSP1) control. A transgenic mouse model was established in which TVA, an avian retroviral receptor gene driven by OSP1, was selectively expressed in the ovary. A recombinant plasmid containing TVA cDNA and an OSP1 promoter was constructed. The DNA fragment was repeatedly injected into male mouse testes at multiple sites. At 4‑7, 7‑10 and 10‑13 weeks following the final injection, two DNA‑injected male mice were mated with four wild‑type female mice to produce transgenic mice. The transgenic positive rate in mouse F1 offspring was 39.69%. When the positive F1 individuals were mated with wild‑type Imprinting Control Region mice (PxW) or with positive F1 individuals (PxP), the F2 individuals had a transgenic rate of 12.44%. The transgenic rates in the F1 offspring, produced following mating at the three time intervals, were 55.71 (39/70), 30.77 (4/13) and 18.75% (9/48), respectively. The transgenic rates of the F2 offspring decreased with the age of the F1 offspring, from 26.67% when PxP were mated at 6‑8 weeks of age to 6.52% when PxW were mated at 5‑6 months of age. The results indicate a high efficiency of gene transfer to F1 offspring using testis‑mediated gene transfer (TMGT). The transgenic rate in the F2 offspring was lower than that in the F1 offspring. The results reveal that TMGT is suitable for creating transgenic animals among F1 offspring. Semi‑quantitative reverse transcription-polymerase chain reaction results showed that TVA was expressed in the mice ovaries. The results demonstrate the importance of using the replication‑competent avian sarcoma‑leukosis virus long terminal repeat with a splice acceptor‑TVA system in ovarian tumorigenesis research.