• Proceedings of the KSAR Conference
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• 2000.10a
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• pp.7-8
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• 2000

Transgenic animals are very useful for scientific, pharmaceutical, and agricultural purposes. In livestock, transgenic technology has been used forthe genetic alteration of farm animals, the production of human proteins inlarge quantities in the milk of transgenic farm animals, and the generation of animals with organs suitable for xenotransplantation. To date, the transfer of foreign genes into farm animals has been performed mainly by microinjection of DNA into the pronuclei of fertilized eggs. However, the overall success rate of transgenic animals in livestock so far has been disappointingly low, eg., the efficiency is 0∼5% in swine, and less than 1% in sheep and cattle, compared with the rate in mice where 5% microinjected develop into transgenic animals. Recently, McGreath et al. (2000) have succeeded in producing the gene targeted sheep by the use of nuclear transfer from cultured somatic cells transfected with a foreign gene in vitro. However, we may need plenty of time until currently employ this method for gene transfer to farm animals. We have been studying to exploit the method for improving production efficiencies of transgenic animals with emphasis of its application to farm animals. The present paper describes three approaches that we have made in our laboratory to improve production efficiencies of transgenic animals, based on the DNA microinjection method. 1. Co-injection of restriction enzyme with foreign DNA into the pronucleus for elevating production efficiencies of transgenic animals. 2. Efficient selection of transgenic mouse embryos using EGFP as a marker gene. 3. Phenotypes of tansgenic mice expressing WAP/hGH-CAG/EGFP fusion gene produced by selecting transgenic embryos. 4. Efficient site-specific integration of the transgene targeting an endogenous lox like site in early mouse embryos.

• Korean Journal of Animal Reproduction
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• v.24 no.4
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• pp.343-346
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• 2000

Transgenic animals are very useful for scientific, pharmaceutical, and agricultural purposes. In livestock, transgenic technology has been used forth genetic alteration of farm animals, the production of human proteins inlarge quantities in the milk of transgenic farm animals (Clark et al., 1989; Ebert et al., 1991; Kimpenfort et al., 1991; Wall et al., 1991; Kimpenfort et al., Well et al,m 1991; Hill et al., 1992; Velander et al., 1994; Chen et al.), and the generation of animals with organs suitable for xenotransplantation (Pinkert, 1994; Chen et al., 1999). (omitted)

• Proceedings of the Korean Society of Embryo Transfer Conference
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• 1998.05a
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• pp.12-28
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• 1998

The technology of creating transgenic animals has a potential value in improving productivity and disease resistance of animals, gene therapy, drug pharming and production of model animals for certain diseases. Up to date, fairly low success rate of production of transgenic animals and a pronounced variability with respect to the expression of transgenes have been much observed. The mechanisms how to integrate the injected genes with a certain part of the genomes are unknown yet. Many techniques in gene transfer, beside microinjection, have been introduced and explored thus to improve the production efficiency of transgenic animals. In this article, the methods and efficiency of gene-transfer techniques, the detection and preselection of transgenes in embryos by PCR- and GFP-screenings and cloning of preselected transgenic embryos by nuclear transplantation are described and discussed. Some experimental results showed that the early screening and selection of integration of the injected gene with embryonic genome by polymerase chain reaction(PCR) and green fluorecence protein(GFP) were promising methods. Further, the application of nuclear transplantation technology to cloning and multiplication of the positively integrated genes in the cleaving embryos and embryonic cells will be beneficially used for the mass production of transgenic embryos and consequently improving the production efficiency in transgenic animals.

• Asian-Australasian Journal of Animal Sciences
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• v.13 no.2
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• pp.244-257
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• 2000

Recent progress in molecular biology has made it possible to transfer genes of interest into cells and target tissues of living animals. This enables one to manipulate phenotype of cells and whole animals in selected and intended ways. The consequence of such gene transfer attempts have been the production of various types of "transgenic" animals that cannot be classified by classical nomenclature of exclusively either "transgenic" or "nontransgenic". Emphasis was placed on characterizing two transgenic categories, i.e., "transfectgenic and somatotransgenic" and "genuine transgenic" animals basically from a view point of their use for therapeutic purposes. Current state of art and possible solutions for problems encountered at present are discussed.

• Asian-Australasian Journal of Animal Sciences
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• v.7 no.1
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• pp.1-17
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• 1994

There are several gene transfer methods available to introduce foreign DNA into animal. The most common method at present is microinjection. However, the overall efficiency of producing practical application of gene transfer technology to livestock species is production of pharmaceuticals. Rare human proteins, which cannot be produced into milk of transgenic animals. Large amount of biologically active protein may be obtained from transgenic farm animals using this system. Growth-related application to livestock species using growth hormone genes or factor genes have been disappointing. There were many undesirable side effects noted in the transgenic animals. More sophisticated on or off transgene expression are needed to control expression of transgenes in the transgenic animals. Turning positive effects while circumventing potentially harmful effects.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.6
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• pp.910-927
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• 2003

Transgenesis is a very powerful tool not only to help understanding the basics of life science but also to improve the efficiency of animal production. Since the first transgenic mouse was born in 1980, rapid development and wide application of this technique have been made in laboratory animals as well as in domestic animals. Although pronuclear injection is the most widely used method and nuclear transfer using somatic cells broadens the choice of making transgenic domestic animals, the demand for precise manipulation of the genome leads to the utilization of gene targeting. To make this technique possible, a pluripotent embryonic cell line such as embryonic stem (ES) cell is required to carry genetic mutation to further generations. However, ES cell, well established in mice, is not available in domestic animals even though many attempt to establish the cell line. An alternate source of pluripotent cells is embryonic germ (EG) cells derived from primordial germ cells (PGCs). To make gene targeting feasible in this cell line, a better culture system would help to minimize the unnecessary loss of cells in vitro. In this review, general methods to produce transgenic domestic animals will be mentioned. Also, it will focus on germ cell engineering and methods to improve the establishment of pluripotent embryonic cell lines in domestic animals.

• Korean Journal of Animal Reproduction
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• v.22 no.2
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• pp.145-152
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• 1998

Many trials have been made to produce transgenic animals using sperm cells as a vector transferring foreign DNA into eggs, but reliable results are yet to be obtained (Brinster et al., 1989; Lavitrano et al., 1989; Bachiller et al., 1991; Sato et al., 1994). Recently, one of author(SO) demonstrated that mouse blastocysts derived from eggs fertilized by spermatozoa of male mice single injected with liposome-DNA complexes within the testis expressed thegene (Ogawa et al., 1995.) Here we report that a single injection of liposome-encapsulated DNAs into the testis of either male rats or mice resulted in successfully gene transfer to the postpartum progeny. The expression of mRNA derived from transgenes was also demonstrated in transgenic animals thus obtained. Further, the transmission of the exogenous gene to the descedants was confirmed in one line of transgenic rat up to F4 generation, indicating that the gene was stably incorporated into the germ line. Thus, direct single injection of foreign DNA into the testis provides a novel and convenient means to generate transgenic animals.

• Korean Journal of Animal Reproduction
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• v.23 no.4
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• pp.381-391
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• 1999

During the last 20 years, transgenic animal technology has provided revolutionary new opportunities in many aspects of agriculture and biotechnology. Several gene delivery systems including pronuclear injection, retroviral vectors, sperm vectors, and somatic cell cloning have developed for making transgenic animals. In the future major improvements in transgenic animal generation will be mainly covered by somatic cell cloning technology. Many factors affecting integration frequency and expression of the transgenes should be overcome to facilitate the industrial applications of transgenic technology. Transgenic animal technology has settled down in some areas of the biotechnology, especially the mass production of valuable human proteins and xenotransplantation. In the 21st century animal biotechnology will further contribute to welfare of human being.

• Journal of Animal Reproduction and Biotechnology
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• v.34 no.2
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• pp.65-69
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• 2019

Since the development of the first genetically-modified mouse, transgenic animals have been utilized for a wide range of industrial applications as well as basic research. To date, these transgenic animals have been used in functional genomics studies, disease models, and therapeutic protein production. Recent advances in genome modification techniques such zinc finger nuclease (ZFN), transcription activator-like effector nucleases (TALEN), and clustered regularly interspaced short palindromic repeats (CRIPSR)-Cas9, have led to rapid advancement in the generation of genome-tailored livestock, as well as experimental animals; however, the development of genome-edited poultry has shown considerably slower progress compared to that seen in mammals. Here, we will focus primarily on the technical strategies for production of transgenic and gene-edited chickens, and their potential for future applications.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.12
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• pp.1732-1737
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• 2003

An experiment was conducted to investigate the effect of feeding transgenic cottonseed (Bt.) vis-a-vis non-transgenic (non-Bt.) cottonseed on blood biochemical constituents in lactating Murrah buffaloes. Twenty Murrah buffaloes in mid-lactation were divided into 2 groups of 10 each. Animals of group I were fed with 39.5% non-transgenic cottonseed in concentrate mixture while the same percentage of transgenic (Bt.) cottonseed was included in the concentrate mixture fed to the animals of group II. Animals of both groups were fed with concentrate mixture to support their milk production requirements. Each buffalo was also offered 20 kg mixed green fodder (oats and berseem) and wheat straw ad libitum. The experimental feeding trial lasted for 35 days. There was no significant difference in the dry matter intake between the two groups of buffaloes. All the buffaloes gained body weight, however, the differences were non significant. Total erythrocyte count, hemoglobin content and packed cell volume were $9.27{\pm}0.70${\times}10^6/{\mu}l$, $13.01{\pm}0.60gdl$ and $34.87{\pm}1.47%$, respectively in group I with the corresponding figures of $8.88{\pm}0.33$, $12.99{\pm}0.52$ and $31.08{\pm}1.52$ in group II. The values of total erythrocyte count, haemoglobin content and packed cell volume did not differ significantly between the two groups of buffaloes. The concentration of plasma glucose, serum total proteins, albumin, globulin, triglycerides and high density lipoprotein were non significantly higher in buffaloes fed non-transgenic cottonseed than in buffaloes fed transgenic cottonseed. The cholesterol concentration was significantly (p<0.01) higher in buffaloes of group I ($136.84{\pm}8.40mg/dl$) than in buffaloes of group II ($105.20{\pm}1.85mg/dl$). The serum alkaline phosphotase, glutamic-oxaloacetate transaminase and glutamic-pyruate transaminase activities did not differ significantly between two groups of buffaloes. However, serum glutamic-pyruate transaminase activity was considerably high in buffaloes fed nontransgenic cottonseed as compared to buffaloes fed transgenic cottonseed. Bt. proteins in serum samples of animals of group II were not detected after 35 days of feeding trial. It was concluded that transgenic cottonseed and non-transgenic cottonseed have similar nutritional value without any adverse effects on health status of buffaloes as assessed from haematobiochemical constituents.