Controllable transgenic expression systems in transgenic animal model are valuable to the development of therapeutic approaches in human medical fields. The aim of this study was to 1) produce a transgenic cloned dog using inducible tetracycline vector system, and 2) investigate whether the transgenic cloned dog could be induced the transgene expression using doxycycline (Doxy). Canine fetal fibroblasts were infected with retroviral vectors designed to express the enhanced green fluorescent protein (eGFP) gene under the control of tetracycline-inducible promoter. For somatic cell nuclear transfer (SCNT), nucleus of an in vivo matured oocyte was removed and an eGFP expressed cell cultured with 1 ㎍/㎖ of Doxy was injected. After electrical fusion and chemical activation, the reconstructed embryos were transferred to a recipient and pregnancy diagnosis was performed by ultrasonography. Experiment I evaluated the mean fluorescence intensity (MFI) of infected cells while the cells were cultured in the presence of 1 ㎍/㎖ of Doxy for 5 days, and then in the absence of Doxy for 7 days using fluorescence-activated cell sorter. Experiment II was designed to produce an eGFP controllable transgenic cloned dog via SCNT. For verification of transgenic dog, experiment III was performed Southern Blot analysis and observation in vivo regulation of eGFP expression in the cloned dog treated with 100 ㎎/㎏ of Doxy every 2 days for 2 weeks under ultraviolet light. In experiment IV, western blot was used to detect eGFP increase and decrease in skin tissues of transgenic dog under the presence or absence of Doxy. In the results of experiment I, the MFI for infected cells was rapidly increased to approximately 42.3 times after 3 day-treatment compared to pre-treatment and quickly decreased 3 days after ceasing the treatment. In experiment II, a total of 203 embryos were transferred to nine recipients and three pregnant delivered three pups (Tet-on eGFP 0, Tet-on eGFP 1, and Tet-on eGFP 2) by C-sec and Tet-on eGFP 2 among them is still alive. All cloned pups were genetically identical to the donor cell. Tet-on eGFP 2 showed an apparent in vivo eGFP expression on her body after Doxy administration in experiment III. The result of Sothern blotting showed that the transgene insertion was detected from the three cloned dogs and all organs of Tet-on eGFP 1. Experiment IV indicated that a robust eGFP expression in skin tissue of Tet-on eGFP 2 rapidly increased after Doxy treatment and gradually decreased to basal level on 9 weeks after ceasing the treatment. In conclusion, we report here for the first time an inducible transgenic system in canine species and it can stably induce the transgene expression at intended time. This study has demonstrated the capacity to generate transgenic model dog which could regulate the transgene and it would contribute to human medical research fields.

추파대맥 2품종을 재배하여 유식물을 청예사료로 이용할 목적으로 생육시기별로 예취할 때 청초의 생산량과 곡실의 수량이 어떠한가를 구명코저 본실험을 실시하였던바 그 시험을 요약하면 다음과 같다. 1. 생초수량은 수원18호가 올보리(Barsoy)보다 증수되었고 2품종 모두 4월30일 1회 예취구의 수량이 가장 많았다. 2. 적중은 올보리 4월18일 1회예취구가 10a당 935.3kg으로 가장 많았고 다음은 수원18호 928kg, 수원18호의 무예취구 833.3kg및 올보리의 무예취구 723.3kg의 순위였다. 3. 수수는 수원18호가 올보리보다 다수였고 기중 수원18호 4월 18일 1회예취구(10a당)의 8,493개가 가장 많았다. 4. 성숙한 식물체중도 수중, 수수에서와 마찬가지로 4월18일에 한번 예취한 것이 2품종 모두 무예취구보다 훨씬 우월하였다. 5. 대맥 품종을 잘 선택하고 시비를 적당히 하면 생육초기에 청예사료를 목적으로 한번쯤 예취를 해도 좋은 곡립의 수량과 청예사료를 얻을 수 있다고 고려 되어진다.