• Journal of Aquaculture
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• v.19 no.3
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• pp.166-172
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• 2006

Induced androgenesis, a form of artificial parthenogenesis is an important tool for the generation and use of genetically isogenic or clonal fish strain. An optimized protocol for the genetic inactivation of mud loach (Misgurnus mizolepis) oocytes (i.e. production of androgenetic haploid) was developed using UV-irradiation. Various dose levels of UV significantly affected the fertilizing capacity of the eggs, hatchability of embryos and incidence of haploidy. Based on the extensive examinations of treatment conditions on embryo viability and haploid incidence, the optimum dose level of UV irradiation was turned out to be $10,800ergs/mm^2$ with 56.9% of hatching success and 94.6% of haploidy. The overall yield of putative androgen under optimized treatment condition was more than 50% out of total eggs inseminated. The success of androgenetic reproduction of haploid genome was verified by flow cytometry and PCR amplification of transgene that is exclusive to either one of parental sexes. However, a small portion $(8\sim11%)$ of presumed androgenetic haploid larvae was proven to contain residual DNA fragment(s) from maternal parent.

• Plant Biotechnology Reports
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• v.4 no.4
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• pp.293-301
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• 2010

The feasibility of two strategies for transgene pyramiding using Agrobacterium-mediated transformation was investigated to develop a transgenic potato (Solanum tuberosum L. cv. Iwa) with resistance to potato tuber moth (PTM) (Phthorimaea operculella (Zeller)). In the first approach, cry1Ac9 and cry9Aa2 genes were introduced simultaneously using a kanamycin (nptII) selectable marker gene. The second approach involved the sequential introduction (re-transformation) of a cry1Ac9 gene, using a hygromycin resistance (hpt) selectable marker gene, into an existing line transgenic for a cry9Aa2 gene and a kanamycin resistance (nptII) selectable marker gene. Multiplex polymerase chain reaction (PCR) confirmed the presence of the specific selectable marker gene and both cry genes in all regenerated lines. The relative steady-state level of the cry gene transcripts in leaves was quantified in all regenerated lines by real-time PCR analysis. Re-transformation proved to be a flexible approach to effectively pyramid genes for PTM resistance in potato, since it allowed the second gene to be added to a line that was previously identified as having a high level of resistance. Larval growth of PTM was significantly inhibited on excised greenhouse-grown leaves in all transgenic lines, although no lines expressing both cry genes exhibited any greater resistance to PTM larvae over that previously observed for the individual genes. It is anticipated that these lines will permit more durable resistance by delaying the opportunities for PTM adaptation to the individual cry genes.

• Journal of Plant Biotechnology
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• v.34 no.1
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• pp.31-36
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• 2007

Though higher plants car not metabolize D-amino acid, many prokaryotes and eukaryotes have the D-amino acid metabolism. Therefore, we transformed tobacco plants with D-amino acid oxidase (DAO), which can metabolize D-amino acid, and confirmed that transgenic tobacco plants might metabolize D-amino acid. Transgenic tobacco plants were survived a high concentration of D-serine, however non-transgenic plants were not grown on D-serine medium. From Southern and Northern blot analysis, transgenic tobacco plants selected on D-serine medium were confirmed by insert and expression of transgene. $T_{1}$ tobacco seeds derived $T_{0}$ tobacco plants selfing were grown on D-serine medium and showed normal phenotype compared to wild tobacco plants. Transgenic tobacco plants displayed the metabolic capability of D-serine. Therefore, we suggested that DAO is useful selectable marker gene for plant transformation.

• Plant Biotechnology Reports
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• v.2 no.1
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• pp.47-58
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• 2008

To select agronomically useful transgenic plants, a large number of transgenic events are initially produced, gene transfer confirmed, and advanced to obtain homozygous lines for testing in field trials. Direct in planta assays for identifying the transgene carriers in the segregating progeny are based on the activity of selectable marker gene and are easy, simple and inexpensive. For this purpose, expression of bar gene as measured by tolerance to damage by glufosinate ammonium, the active ingredient in the herbicide BASTA, was investigated. Dose damage curves were generated by leaf paint tests with BASTA on four genotypes of sorghum. Transgenic plants were characterized in terms of sensitivity to the concentration of glufosinate ammonium. In transgenics, symptoms of BASTA swab tests at different growth stages and PCR analysis for cry1B were carried out and correlated. Germination tests could not be employed for large scale evaluation of transgenic progeny because of mortality of tolerant seedlings after transplantation to soil. Based on the above findings, a simple, inexpensive, time-saving, two-step scheme for effective evaluation of transgenics and their progeny containing bar gene as selection marker using BASTA swab tests is described.

• Reproductive and Developmental Biology
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• v.33 no.1
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• pp.63-69
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• 2009

In this study we tried to construct a more efficient tetracycline-inducible gene expression system by replacing previous key elements with more advance ones. At the beginning, we substituted PGK (phophoglycerate kinase) promoter for CMV (cytomegalovirus) promoter to control "$rtTA2^sM2$" which has been known for high induction efficiency in response to tetracycline. With this modification, expression of the EGFP marker gene under the induction condition was significantly increased. Next, we replaced "TRE" fragment with a modified version named "TRE-tighf" which has been reported to have higher affinity and specificity to the transactivator by minor base change of the "TRE" DNA fragment sequence. Use of "TRE-tighf" instead of "TRE" resulted in more than 10 fold increment in terms of induction efficiency and significant decrement of background expression in non-inducible condition. By combining PGK promoter and "TRE-tight" fragment, we could upgrade previous tetracycline-inducible system to show more stringent turn on/off gene switch ability and stronger expression of the gene of our interest. Use of this newly developed system must be very helpful to the studies of gene expression, especially to the transgenic animal study in which non-controllable constitutive expression of the transgene has been one of the urgent problems to be solved.

• International Journal of Oral Biology
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• v.36 no.3
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• pp.135-141
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• 2011

Hertwig's epithelial root sheath (HERS) consists of bi-layered cells derived from the inner and outer dental epithelia and plays important roles in tooth root formation as well as in the maintenance and regeneration of periodontal tissues. With regards to the fate of HERS, and although previous reports have suggested that this entails the formation of epithelial rests of Malassez, apoptosis or an epithelial-mesenchymal transformation (EMT), it is unclear what changes occur in the epithelial cells in this structure. This study examined whether HERS cells undergo EMT using a keratin-14 (K14) cre:ROSA 26 transgenic reporter mouse. The K14 transgene is expressed by many epithelial tissues, including the oral epithelium and the enamel organ. A distinct K14 expression pattern was found in the continuous HERS bi-layer and the epithelial diaphragm were visualized by detecting the ${\beta}$-galactosidase (lacZ) activity in 1 week postnatal mice. The 2 and 4 week old mice showed a fragmented HERS with cell aggregation along the root surface. However, some of the lacZ-positive dissociated cells along the root surface were not positive for pan-cytokeratin. These results suggest that the K14 transgene is a valuable marker of HERS. In addition, the current data suggest that some of the HERS cells may lose their epithelial properties after fragmentation and subsequently undergo EMT.

• Journal of Korean Society of Forest Science
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• v.84 no.1
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• pp.77-86
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• 1995

To effectively modify tree function with genetic engineering, transgenes must be expressed at the proper level in the appropriate tissues at suitable developmental stages. Toward understanding the spatial and temporal expression of transgenes in woody plants, transgene expression was evaluated in three greenhouse-grown, transgenic lines of Populus alba ${\times}$ P. grandidentata hybrid clone 'Hansen'. All transgenic poplar lines possess constructs containing the bacterial nopaline synthase(nos) promoter linked to a neomycin phosphotransferase II(NPT II) selectable marker gene. In addition, each transgenic poplar line contains one of the following gene constructs : 1) a wound-inducible potato proteinase inhibitor II (pin2) promoter linked to a chloramphenicol acetyltransferase(CAT) reporter gene. 2) a nos promoter linked to a PIN2 structural gene : or 3) a Cauliflower Mosaic Virus 35s promoter linked to a PIN2 structural gene. Polymerase chain reaction(PCR) was used to verify the presence of foreign genes in the poplar genome. Enzyme-linked immunosorbent assays(ELISAs) were used to evaluate organ specific expression of the nos-NPT II construct. NPT II expression was detected in leaves, petioles, stems, and roots of transgenic poplar, thereby indicating that the nos promoter is potentially effective for general constitutive expression of transgenes. NPT expression varied among transgenic poplar lines and among organs for one transgenic line, Tr15. With Tr15, NPT II levels were highest in older leaves and petioles. These results indicate that screening of several transgenic lines may be required to identify lines with optimal transgene expression.

• Journal of Plant Biotechnology
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• v.34 no.4
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• pp.347-354
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• 2007

Commercialization of genetically modified (GM) plants will be required the assessment of risks associated with the release of GM plants that should include a detailed risk assessment of their impacts in human health and the environment. Prior to GM plant release, applicants should provide the information on GM crops for approval. We carried out this study to provide the molecular data for risk assessment of the GM Chinese cabbage plants with insect-resistance gene, modified CryIAc, which we obtained by Agrobacterium-transformation. From the molecular analysis with GM Chinese cabbage, we confirmed the transgene copy number and stability, the expression of the transgene, and integration region sequences between the transgene and the Chinese cabbage genome. Based on the unique integration DNA sequences, we designed specific primer set to detect GM Chinese cabbage and set up the GM cabbage detection method by qualitative PCR analysis. Qualitative analysis with GM Chinese cabbage progenies analysis was revealed the same as the result of herbicide treatment. Our results provided the molecular data for risk assessment analysis of GM Chinese cabbage and demonstrated that the primer set proposed could be useful to detect GM Chinese cabbage.

• Animal Bioscience
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• v.34 no.8
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• pp.1321-1330
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• 2021

Objective: Transgenic hens hold a great promise to produce various valuable proteins. Through virus transduction into stage X embryo, the transgene expression under the control of constructed chicken ovalbumin promoters has been successfully achieved. However, a validation system that can evaluate differently developed ovalbumin promoters in in vitro, remains to be developed. Methods: In the present study, chicken oviduct epithelial cells (cOECs) were isolated from oviduct tissue and shortly cultured with keratinocyte complete medium supplemented with chicken serum. The isolated cells were characterized with immunofluorescence, western blot, and flow cytometry using oviduct-specific marker. Chicken mutated ovalbumin promoter (Mut-4.4-kb-pOV) was validated in these cells using luciferase reporter analysis. Results: The isolated cOECs revealed that the oviduct-specific marker, ovalbumin protein, was clearly detected by immunofluorescence, western blot, and flow cytometry analysis revealed that approximately 79.40% of the cells contained this protein. Also, luciferase reporter analysis showed that the constructed Mut-4.4-kb-pOV exhibited 7.1-fold (p<0.001) higher activity in the cOECs. Conclusion: Collectively, these results demonstrate the efficient isolation and characterization of cOECs and validate the activity of the constructed ovalbumin promoter in the cultured cOECs. The in vitro validation of the recombinant promoter activity in cOECs can facilitate the production of efficient transgenic chickens for potential use as bioreactors.

• Journal of Plant Biotechnology
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• v.7 no.4
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• pp.211-218
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• 2005

Genetic transformation was carried out by using biolistic gun method. The hypocotyl derived embryogenic calli (explants) of cotton (Gossypium hirsutum L.) cv. Cocker-312 were transformed with a recombinant pGreen II plasmid, in which both, bar (selection marker) and GUS (${\beta}$-glucuronidase) reporter genes were incorporated. Explants were arranged on osmoticum-containing medium (0.5M mannitol) 4 hours prior to and 16 hours after bombardment that was resulted into an increase about >80% for GUS stable expression. 3 days after bombardment, GUS assay was performed, which exhibited, $18.36{\pm}1.00$ calli showed blue spots. The transformed embryogenic calli were cultured on selection medium (@ 6 mg/L basta) for 3 months. The putative transgenic plants were developed via selective somatic embryogenesis (@1.50 mg/L basta); maximum $27.58{\pm}1.25$ somatic embryos were obtained while $17.47{\pm}1.00$ embryos developed into plantlets (@ 0.75mg/L basta). In five independent experiments, up to 7.24% transformation efficiency was recorded. The presence of the transgenes was analyzed by using PCR and southern hybridization analysis. The transgenic plants were developed with in 6-7 months, but mostly transformants were abnormal in morphology.