• Journal of Sericultural and Entomological Science
• /
• v.51 no.1
• /
• pp.73-77
• /
• 2013

Silkworm transgenesis scientists have done some genetic modification work on multivoltine silkworms, but that type of silkworms is less commercial feasible. They are easy to manipulate, because they breed all year round. But the commercial silkworm variety must undergo hydrochloric acid treatment at a high temperature to be artificially hatched. Hydrochloric acid penetrates through the holes in the silkworm eggs, fatally damaging their reproduction. So it had been thought that altering the properties of the commercial silkworm variety would be very difficult. So we have tried to make from diapause to non-diapause eggs using diapauses varieties, 'Backokjam' and 'Jam 124'. At present, our group has establishing the conditions for non-diapause eggs. Oviposited eggs after 40 ~ 60 hours were incubated for 24 hours at $15{\sim}20^{\circ}C$ with dark condition. Non-diapause eggs were completely induced. The hatching rate, molting rate and pupation rate of non-diapause 'Jam 124' and 'Backokjam' eggs showed no differences compared to diapause eggs. When transgenic silkworm using the non-diapause eggs, the hatching rate showed that non-diapause eggs induced from diapause were 40 ~ 70%, diapause eggs treated with artificial incubation were 10 ~ 30%, and polyvoltine strains, HM eggs were 30 ~ 50%. Therefore, we suggest that modification techniques of the commercial silkworm eggs adequate for silkworm transgenesis can be used to develop transgenic silkworms more easily.

• Proceedings of the Korean Society of Embryo Transfer Conference
• /
• 2003.10a
• /
• pp.20-21
• /
• 2003

• BMB Reports
• /
• v.51 no.9
• /
• pp.437-443
• /
• 2018

Non-homologous end joining (NHEJ), and to a lesser extent, the error-free pathway known as homology-directed repair (HDR) are cellular mechanisms for recovery from double-strand DNA breaks (DSB) induced by RNA-guided programmable nuclease CRISPR/Cas. Since NHEJ is equivalent to using a duck tape to stick two pieces of metals together, the outcome of this repair mechanism is prone to error. Any out-of-frame mutations or premature stop codons resulting from NHEJ repair mechanism are extremely handy for loss-of-function studies. Substitution of a mutation on the genome with the correct exogenous repair DNA requires coordination via an error-free HDR, for targeted transgenesis. However, several practical limitations exist in harnessing the potential of HDR to replace a faulty mutation for therapeutic purposes in all cell types and more so in somatic cells. In germ cells after the DSB, copying occurs from the homologous chromosome, which increases the chances of incorporation of exogenous DNA with some degree of homology into the genome compared with somatic cells where copying from the identical sister chromatid is always preferred. This review summarizes several strategies that have been implemented to increase the frequency of HDR with a focus on somatic cells. It also highlights the limitations of this technology in gene therapy and suggests specific solutions to circumvent those barriers.

• Asian-Australasian Journal of Animal Sciences
• /
• v.16 no.6
• /
• pp.910-927
• /
• 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
• /
• v.17 no.3
• /
• pp.263-267
• /
• 1993

Transgenic animals have become an important tool in the basic and applied sectors of genetic and biomedical sciences. In particular transgenes provide clear-cut markers in the spatial and temporal analysis of developing embryos for the understanding of developmental mechanisms. For the long-term use of plasmid vector in a particular purpose it would be necessary to develop one's own vector system which can be properly expressed in eukaryotic system. Plasmids were constructed from ori region of pUC19 and early region of SV40 through various steps. LacZ gene coding for $\beta$-galactosides was fused to early gene of SV40 in translational in-frame. Poly(A) tailing site of SV40 was inserted at the 3' lacZ so that initiation, elongation and terminatin be controlled by SV40 transcription (pSS4). Biological function of the constructed pSS4 was demonstrated via microinjection of the plasmid into fertilized loach eggs and subsequent detection of $\beta$-galactosidase in developing embryos. The result indicate that the newly constructed pSS4 is functional in a eukaryotic system in vivo. Thus pSS4 may be used as an efficient tool for the study of embryogenesis and a basic carrier for various genes for animal transgenesis.

• Journal of Microbiology and Biotechnology
• /
• v.28 no.12
• /
• pp.1955-1970
• /
• 2018

Several genetic strategies have been proposed for the successful transformation and expression of microbial transgenes in model and crop plants. Here, we bring into focus the prominent applications of microbial transgenes in plants for the development of disease resistance; mitigation of stress conditions; augmentation of food quality; and use of plants as "bioreactors" for the production of recombinant proteins, industrially important enzymes, vaccines, antimicrobial compounds, and other valuable secondary metabolites. We discuss the applicable and cost-effective approaches of transgenesis in different plants, as well as the limitations thereof. We subsequently present the contemporary developments in targeted genome editing systems that have facilitated the process of genetic modification and manifested stable and consumer-friendly, genetically modified plants and their products. Finally, this article presents the different approaches and demonstrates the introduction and expression of microbial transgenes for the improvement of plant resistance to pathogens and abiotic stress conditions and the production of valuable compounds, together with the promising research progress in targeted genome editing technology. We include a special discussion on the highly efficient CRISPR-Cas system helpful in microbial transgene editing in plants.

• Proceedings of the KSAR Conference
• /
• 2004.06a
• /
• pp.170-170
• /
• 2004

First of all, in vitro production (IVP) of porcine embryos is an important as initial step to improve bio-technical applications such as transgenesis and cloning for xenotransplantation. In recent years, considerable progress has been achieved in the IVP embryos using advanced methods for in vitro maturation (IVM) and fertilization (IVF). (omitted)

• Proceedings of the Korean Society of Developmental Biology Conference
• /
• 2005.10a
• /
• pp.122-123
• /
• 2005

• Proceedings of the Korean Society of Embryo Transfer Conference
• /
• 2005.10a
• /
• pp.122-123
• /
• 2005

• Proceedings of the KSAR Conference
• /
• 2003.06a
• /
• pp.98-98
• /
• 2003

Direct gene transfer to mammalian tissues has significant potential for gene therapy and transgenesis. Liposome-mediated in vivo transfection has begun to gain attention as an alternative to viral vectors, and may also be a good mode of transfection in gene transfer. Interestingly, polymerized cationic liposomes are reported to be very stable in the bloods and efficient for in vivo gene transfer. To examine a possible gene delivery in vivo, we investigated the efficacy and safety of the liposome-mediated gene transfer using vein injection in chick or mouse as model animals. The number of injected pGFP-LacZ using either a commercial or home-made liposomes was 8 and 19 at 16 and 7 day of hatch, respectively. One of injected chick of each experiments was analyzed and the rest is being bred. In mouse, 4/22 showed expression of pGFP-LacZ but 8/22 showed no expression and the remaining animals are also being bred. After injection of liposome/pGFP-LacZ complex into wing vein of 7 or 16 day-old chick, pGFP-LacZ was detected in various tissues isolated from not only young chick but also old chick were turned out to possess. exogenous DNA. Transcripts and proteins of the transgene were also detected by RT-PCR or histochemical analysis, respectively. These results suggest that injected DNA were inserted to genome and produced mRNA and proteins in various tissues and may give an important tools for effective gene delivery in gene therapy or transgenesis.