• 한국가축번식학회지
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• 제14권3호
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• pp.191-197
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• 1990

The transgenic mice were produced by microinjection of human growth hormone gene fused with mouse metallothionein Ⅰ promoter. They were mated with momal mice by backcross or brother-sister mating. The reproduction efficiencies of female and male n the FO transgenic mice were 17.6%(3/17 mice) and 31.2%(5/16 mice), respectively, and were very lower than that in normal mice(85.7% and 100%, respectively). Interestingly, a few of female transgenic mice were fertile which was different from the previous reports. Of 6 fertile transgenic mice, 2 mice were identified as mosaic type by the reduced frequency of genetic transmission to successive generation below Mendelian levle and the enhanced copy numbers of transgene in progeny mice compared with the transgenic parent. In the group of F1, F2, F3 transgenic mice the reproduction efficiencies of males were gradually improved, whereas females were absolutely infertile. It was consequently shown that the transgenic mice expressing human growth hormone gene were frequently infertile, but the genotypic and phenotypic characteristics of the fertile transgenic mice were normally passed on to the progeny through herm line. Therefore it must be considered wheter or not the products of foreign DNA introduced into animals will detrimentally affect their physiological aspects.

• Reproductive and Developmental Biology
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• 제33권2호
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• pp.113-117
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• 2009

Animals produced by somatic cell nuclear transfer (SCNT) using genetically modified cells are almost always transgenic, implying that this method is more efficient than the traditional pronuclear microinjection method. Most somatic cells for SCNT in animals are fetus-derived primary cells and successful gene integration in somatic cells will depend on transfection condition. The objective of this study is to evaluate the efficiency of electroporation (Microporator) and liposome reagents (F-6, F-HD, W-EX, W-Q, W-M) for tissue-type plasminogen activator (tPA) gene transfection and to estimate the overall efficiency of transfection of Korean native pig fetal fibroblast cells (KNPFF). Electroporation showed significantly higher transfection efficiency than liposome reagents with regard to the transfection of in vitro cultures in the early stages of development (41.7% with Microporator vs. 18.3% with F-6, 20.0% with F-HD 18.5% with W-EX, 5.0% with W-M and 6.3% W-Q,). Colonies identified as tPA-positives were treated once more with G418 for 10 to 14 days and growing colonies were selected again. When the cells of newly selected colonies were subjected to single-cell PCR, reselection of colonies following second round of G418 selection increased the rate of transgene integration per each colony. These results suggest that transfection with electroporation is the most efficient and the second rounds of G418 selection may be an effective method for transfection of porcine fetal fibroblast cells.

• Toxicological Research
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• 제17권
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• pp.293-297
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• 2001

The international pharmaceutical and regulatory communities had been recognizing the limited utility of conventional rodent carcinogenicity study particularly on the second species, mouse, after intense investigation of carcinogenicity data base worldwide, and a new scheme for carcinogenicity testing for pharmaceuticals was proposed at the Expert Working Group on Safety in the International Conference on Harmonization (ICH) in 1996. CB6F 1-Tg rasH2 mouse carrying human prototype c-Ha-ras gene with its own promoter/enhancer is one oj the new carcinogenicity assay model for human cancer risk assessment. Studies have been conducted since 1992 to validate the transgenic (Tg) mice for rapid carcinogenicity test-ing, short term (26 weeks) studies with genotoxic (by Salmonella), non-genotoxic carcinogens, genotoxic non-carcinogens, non-genotoxic non-carcinogens revealed relatively high concordance oj the response of the Tg mouse with classical bioassay across classes of carcinogenic agents. Mechanistic basis for carcinogensis in the model are being elucidated in terms of the role of overexpression and/or point mutation of the transgene. This report review the initial studies of validation of the model and preliminary results of on-going ILSI HESI ACT project will be presented.

• 한국가축번식학회지
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• 제27권2호
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• pp.179-185
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• 2003

본 연구는 생체 내 세포 및 조직배양기로서의 면역결핍동물을 개발할 목적으로 proximal Ick promoter와 DT-A유전자를 이용하여 형질전환생쥐를 생산하였고 형질전환생쥐의 면역기관에서 Di-phteria toxin이 발현되어 T-cell이 결핍되는지를 분석하였다. 총 암수 2마리의 형질전환생쥐를 PCR과 South-ern blotting으로 분석하여 얻었으며 이식유전자의 copy수는 약 2∼3 copy가 정착된 것으로 확인되었다. 형질전환생쥐의 thymus, spleen, liver 조직을 분리한 후 total RNA를 추출하여 poly(dT) primer 와 DT 특이적 primer를 이용하여 RT-PCR수행 결과 형질전환생쥐의 thymus, spleen, liver에서 DT gene이 발현되고 있는 것을 확인할 수 있었다. 형질전환생쥐의 이들 조직간에 DT 발현량에는 큰차이는 없는 것으로 확인되었다. 형질전환생쥐의 혈액에서 적혈구, 백혈구 ,혈소판, 헤모글로빈 등이 정상생쥐보다 감소되었고 특히 백혈구수와 혈소판의 수가 크게 감소되어 있는 것으로 나타났다. 또한 형질전환생쥐의 혈액을 CD3 antibody를 이용하여 FACS 분석을 실시하여 형질전환생쥐의 혈액 중 T-cell이 수가 비정상적으로 줄어든 것을 확인할 수 있었다. 본 연구에서는 Ick-DT 형질전환생쥐에서 DT유전자의 발현에 의한 T-cell 결핍을 유도할 수 있는 것으로 나타나 이를 바탕으로 돼지를 이용한 사람의 이종장기 배양용 형질전환동물을 생산하여 응용될 수 있을 것으로 사료된다.

• BMB Reports
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• 제44권8호
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• pp.535-540
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• 2011

Reprogramming errors, which appear frequently in cloned animals, are reflected by aberrant gene expression. We previously reported the aberrant expression of TIMP-2 and PBEF in cloned placenta and differential expression of PBEF genes during pregnancy. To examine the epigenetic modifications that regulate dynamic gene expression in developing placentae, we herein analyzed the mRNA and protein expression levels of PBEF and TIMP-2 in the placentae of normal mice during pregnancy and then examined potential correlations with epigenetic modifications. DNA methylation pattern analysis revealed no difference, but ChIP assays using antibodies against H3-K9/K14 and H4-K5 histone acetylation revealed that the H3-K9/K14 acetylation levels, but not the H4-K5 acetylation levels, of the TIMP-2 and PBEF loci were significantly correlated with their gene expression levels during placentation in normal mice. These results suggest that epigenetic changes may regulate gene expression level in the developing placentae of normal mice and that inappropriate epigenetic reprogramming might be one cause of the abnormal placentae seen in cloned animals.

• 한국가축번식학회지
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• 제18권3호
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• pp.191-197
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• 1994

광수용기에서 특이적 발현을 유도하는 로돕신 유전자에 존재하는 다양한 점 돌연변이 의해서 일반적으로 색소성 망막염을 초래한다. 이 질병의 측징은 광수용기 세포의 퇴화로 인한 광수용기의 기능상실을 초래하고, 결과적으로 시각상실을 유발한다. 로돕신 유전자는 광수용기의 바깥분절에 존재하며, 빛 에너지를 흡수하여, 시각반응을 야기한다. 본 실험에 사용된 로돕신 유전자는 총 12.5kb의 돼지 로돕신 게놈 유전자로서, 망막에서 특이발현을 유도하는 4kb의 프로모터, 돌연변이를 지닌 5.6kb의 유전자, 그리고 poly A site로 구성되어 있다. 호르몬 투여에 의해 과배란이 유기된 C57BL/6J 생쥐 난자의 웅성전핵에 미세주입법에 의해 도입한 후, 위임신한 생쥐의 난관에 이식하였다. 그 결과 태어난 산자로부터 돌연변이 로돕신 유전자를 지닌 6마리의 형질전환동물을 PCR과 Southern blot analysis를 통하여 확인할 수 있었다. 또한, 이 형질전환 동물들은 로돕신 유전자를 그 자손에게 안정적으로 전달하는 것을 확인하였다. 본 연구는 광수용기 퇴화의 원인규명 및 치료방법을 연구하기 위하여 돌연변이를 지닌 질환모델동물을 생산하는데 있다. 이들 형질전환 동물은 로돕신 유전자의 돌연변이에 의해 야기되는 시각상실의 기전에 관한 연구와 사람의 장님을 치료하기 위한 질환모델동물로서 유용하게 이용될 것이다.

• 한국발생생물학회지:발생과생식
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• 제13권3호
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• pp.191-198
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• 2009

In an attempt to simultaneously produce two human proteins, hGH and hG-CSF, in the milk of transgenic mice, we constructed goat $\beta$-casein-directed hGH and hG-CSF expression cassettes individually and generated transgenic mice by co-injecting them into mouse zygotes. Out of 33 transgenic mice, 29 were identified as double transgenic harboring both transgenes on their genome. All analyzed double transgenic females secreted both hGH and hG-CSF in their milks. Concentrations ranged from 2.1 to $12.4\;mg/m{\ell}$ for hGH and from 0.04 to $0.13\;mg/m{\ell}$ for hG-CSF. hG-CSF level was much lower than hGH level but very similar to that of single hG-CSF mice, which were introduced with hG-CSF cassette alone. In order to address the causes of concentration difference between hGH and hG-CSF in milk, we examined mRNA level of hGH and hG-CSF in the mammary glands of double transgenic mice and tissue specificity of hG-CSF mRNA expression in both double and single transgenic mice. Likewise protein levels in milk, hGH mRNA level was much higher than hG-CSF mRNA, and hG-CSF mRNA expression was definitely specific to the mammary glands of both double and single transgenic mice. These results demonstrated that two transgenes have distinct transcriptional potentials without interaction each other in double transgenic mice although two transgenes co-integrated into same genomic sites and their expressions were directed by the same goat $\beta$-casein promoter. Therefore goat $\beta$-casein promoter is very useful for the multiple production of human proteins in the milk of transgenic animals.

• Reproductive and Developmental Biology
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• 제29권4호
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• pp.235-239
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• 2005

This study was conducted to test whether the transgenic cattle pass the transgene to their progeny through germ cells, and whether the transgene is expressed in the mammary gland of ransgenic cows. Two male ransgenic calves were born from IVF-derived embryos injected with bovine $\beta-casein/human$ lactoferrin fusion gene and then grew up to be reproducible. Semen was collected from a transgenic bull after 18 mon of age and then frozen. Bovine oocytes matured in vitro were fertilized with spermatozoa of the transgenic bull and cultured in $50\;{\mu}L$ drops of CRlaa medium supplemented with 3 mg/mL BSA. After 48 h of culture, cleaved embryos were determined for the presence of transgenes by DNA polymerase chain reaction (PCR). Proportion of transgene positives among bovine embryos fertilized with sperm of the transgenic bull was $20.9\%$ (28/134). One of transgenic bulls did not produce transgenic sperm. Out of 34 calves produced from recipient heifers inseminated with semen of the other bull, 3 $(8.8\%)$ were transgenic animals (2 females and 1 male). Thus, one transgenic bull showed a low transmission frequency below Mendelian levels in both the IVF-derived embryos and his progeny. It was demonstrated by Southern blot that copy numbers of the transgene in the transgenic progeny enhanced about 1.8 times as compared to those of the founder bull The results demonstrate that the transgenic bull carrying human lactoferrin gene could pass his transgene to the progeny through germ cells, although he is a germ-line mosaic.

• Reproductive and Developmental Biology
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• 제40권1호
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• pp.7-13
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• 2016

Effectiveness of transgene transfer into genome is crucially concerned in mass production of the bio-pharmaceuticals using genetically modified transgenic animals as a bioreactor. Recently, the mammary gland has been considered as a potential bioreactor for the mass production of the bio-pharmaceuticals, which appears to be capable of appropriate post-translational modifications of recombinant proteins. The mammary gland tissue specific vector system may be helpful in solving serious physiological disturbance problems which have been a major obstacle in successful production of transgenic animals. In this study, to minimize physiological disturbance caused by constitutive over-expression of the exogenous gene, we constructed new retrovirus vector system designed for mammary gland-specific expression of the hEPO gene. Using piggyBac vector system, we designed to express hEPO gene under the control of mammary gland tissue specific and lactogenic hormonal inducible goat ${\beta}$-casein or mouse Whey Acidic Protein (mWAP) promoter. Inducible expression of the hEPO gene was confirmed using RT-PCR and ELISA in the mouse mammary gland cells treated with lactogenic hormone. We expect the vector system may optimize production efficiency of transgenic animal and reduce the risk of global expression of transgene.

• Reproductive and Developmental Biology
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• 제37권2호
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• pp.85-89
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• 2013

For more than two decades, the intracytoplasmic sperm injection (ICSI) technique has been used as a valuable tool to provide opportunities for studying fertilization, treating human infertility, and producing transgenic animals. Not only in facilitating fertilization but also in propagating mammalian species, ICSI has enhanced the potential of assisted reproductive technologies in human. Polyspermic fertilization has been one of major problems in pig reproduction, but the ICSI helped to solve the problem, and used widely to generate transgenic piglets. Although the ICSI technique is considered to be a very useful tool in assisted reproductive technologies, including generation of transgenic animals, there are some disadvantages using the technique. In this review, we describe the ICSI technique and its application in animal production and human infertility, and discuss advantage and disadvantage of the technique in mammals.