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.

한국의 기후에 적응성이 높은 초연, 내한, 다수성 Triticale을 육성하기 위하여 단간조숙성인 밀 품종 중국 8001(Triticale aestivum)와 내한, 내병성 재래종 호밀(S. Cereale)간의 속간교잡 F1 의 염색체배가로 8배체 Primary Triticale의 육성결과는 다음과 같다. 1. 조숙성 및 중국 8001와 (AABBDD)와 내한, 내병성 재래종 메밀(RR)간의 속간교잡 F1 의 염색체배가로 8배체 Primary Triticale(AABBDDRR)이 육성되었다. 2. 육성된 8배체 Triticale은 양친보다 형태적으로 크고 강건하였다. 특히 수장이 길고 일수영화수가 많았으나 결실율은 24% 정도로 낮았으며 수수에는 호밀에서 유래된 것으로 보이는 모용가 있었다. 3. Primary Triticale의 체세포내 염색체 행동은 규즉적이었으나 Univalent가 많았고 정상적인 분열을 보인 것은 22% 정도였다.