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

• Journal of Plant Biotechnology
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• v.36 no.2
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• pp.115-123
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• 2009

In recent years, several genetically modified (GM) crops have been developed worldwide through the recombinant DNA technology and commercialized by various agricultural biotechnological companies. Commercialization of GM crops will be required the assesment of risks associated with the release of GM crops. In advance of the commercial release of GM crops, developer should submit the several information on GM crops for approval. In this study, we carried out to provide the molecular data for the risk assessment of GM rice containing insect-resistant gene, modified Cry1Ac (CryIAc1). Through the molecular analysis with CryIAc1 induced GM rice, we confirmed the steady integration and expression of transgene, the transgene copy number, the adjacent region sequences of inserted gene into rice genome, and the transgene stability in progenies. For the qualitative PCR detection methods, specific primer pairs were designed on the basis of integration sequences, and construct- and event-specific detection markers were developed for leaf folder-resistant rice, Cr7-1 line. From these results, we demonstrated that the molecular data and the PCR detection methods of leaf folderresistant GM rice could be acceptable to conduct the biosafety and environment risk assessment.

• Plant Biotechnology Reports
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• v.3 no.4
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• pp.325-331
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• 2009

To efficiently express a gene of interest in transgenic plants, the choice of promoter is a crucial factor as it directly affects the expression of the transgene that will yield the desired phenotype. The Arabidopsis ${\beta}-carotene$ hydroxylase 1 gene (AtBch1) shows constitutive and ubiquitous expression and was thus selected as one of best candidates for constitutive promoter analysis by both in silico northern blotting and semi-quantitative RT-PCR analysis. To investigate AtBch1 promoter activity, the 1,981-bp 5'-upstream region of this gene was fused with ${\beta}-glucuronidase$ (GUS) and transformed into Arabidopsis. Through the molecular characterization of transgenic leaf tissues, the AtBch1 promoter generated strong activity that drives 1.8- and 2-fold higher GUS expression than the cauliflower mosaic virus 35S (35S) promoter at the transcriptional and translational levels, respectively. Furthermore, the GUS enzyme activity driven by the AtBch1 promoter was 2.8-fold higher than that produced by the 35S promoter. By histochemical GUS staining, the ubiquitous expression of the AtBch1 promoter was observed in all tissues of Arabidopsis. Semi-quantitative RT-PCR analysis with different tissues further showed that this promoter serves as a strong constitutive driver of transgene expression in dicot plants.

• Horticultural Science & Technology
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• v.29 no.2
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• pp.123-129
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• 2011

To identify unintended vertical gene-transfer rates from the developed transgenic plants, rapid and unequivocal techniques are needed to identify event-specific markers based on flanking sequences around the transgene and to distinguish zygosity such as homo- and hetero-zygosity. To facilitate evaluation of zygosity, a polymerase chain reaction technique was used to analyze a transgenic pepper line B20 (homozygote), P915 wild type (null zygote), and their F1 hybrids, which were used as transgene contaminated plants. First, we sequenced the 3'-flanking region of the T-DNA (1,277 bp) in the transgenic pepper event B20. Based on sequence information for the 3'- and 5'-flanking region of T-DNA provided in a previous study, a primer pair was designed to amplify full length T-DNA in B20. We successfully amplified the full length T-DNA containing 986 bp from the flanking regions of B20. In addition, a 1,040 bp PCR product, which was where the T-DNA was inserted, was amplified from P915. Finally, both full length T-DNA and the 1,040 bp fragment were simultaneously amplified in the F1 hybrids; P915 ${\times}$ B20, Pungchon ${\times}$ B20, Gumtap ${\times}$ B20. In the present study, we were able to identify zygosity among homozygous transgenic event B20, its wild type P915, and hemizygous F1 hybrids. Therefore, this novel zygosity identification technique, which is based on PCR, can be effectively used to examine gene flow for transgenic pepper event B20.

• Proceedings of the Botanical Society of Korea Conference
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• 1996.07a
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• pp.48-60
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• 1996

We previously identified and characterized a predominantly pollen-expressed gene of Petunia inflata that encodes a receptor-like kinase named PRK1. The extracellular domain of PRK1 contains leucine-rich repeats which have been implicated in protein-protein interactions, and the cytoplasmic domain was found to autophosphorylate on serine and tyrosine. To investigate the function PRK1 in pollen development, we transformed P. inflata plants with a construct containing the promoter of a predominantly pollen-expressed gene of tomato, LAT52, fused to an antisense PRK1 cDNA corresponding to part of the extracellular domain of PRK1, There transgenic plants were found to each produce approximately equal amounts of normal and aborted pollen. Analysis of the inheritance of the transgene inserts in two of the transgenic plants, ASRK-13 and ASRK-20, to their progeny revealed that certain transgene inserts cosegregated with the pollen abortion phenotype. Microscopic examination of the aborted pollen grains showed that their outer wall, the exine, was essentially normal, but that their cytoplasm contained only starch-like granules. Staining of the nuclei of the microspores at different stages of uninucleate stage. However, at subsequent stages half of the microspores completed mitosis and developed into normal binucleate pollen, but the other half initially remained uninucleate, then lost their nucleio. Analysis of the amounts of PRK1 mRNA and the antisense PRK1 transcript suggested that the pollen abortion phenotype most likely resulted from down-regulation of the PRK1 gene by the antisense PRK1 transgene. These results suggest that PRK1 plays an essential role in a signal transduction pathway that mediates post-meiotic development of microspores.

• Journal of Plant Biotechnology
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• v.33 no.3
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• pp.185-194
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• 2006

Chloroplasts are believed to be descended from certain cyanobacteria, which were taken up by phagocytosis into a host cell and lived there in a symbiotic relationship. In contrast to the current static concept on the chloroplast genome, its dynamism has been recently demonstrated: the chloroplast genome is active in intramolecular homolgous recombination, producing subgenomic circles when it obtains homolgous sequences via genetic transformation. Chloroplast tranformation in higher plants provides many advantages over nuclear transformation that include higher expression levels of transgenes, polycistronic expression of transgenes, and maternal transmission of transgenes. Tobacco has been used as a model for chloroplast genetic transformation. However, it is recently possible to transform the chloroplasts of other major food and economic crops including rice, soybean, and cotton. Chloroplast-transformed crops will be able to replace bioreactors using microorganisms for production of value-added proteins in future.

• Korean Journal of Ichthyology
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• v.9 no.1
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• pp.91-98
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• 1997

The transgene, pFV4CAT, containing CAT reporter gene regulated by carp $\beta$-actin promoter, was expressed in independent transgenic mud loach germ lines, determined by reverse transcriptase-PCR (RT-PCR) and enzyme-linked immunosorbant assay (ELISA). Expression of the transmitted transgene was found to be tissue-specific in F1 and F2 generations. Tissue specificity of the expression was dependent on each transgenic line with reproducible patterns. Liver and spleen did express the transgene more frequently than other tissues tested, and muscle and heart revealed the higher amount of CAT than other tissues, while testes showed the lowest expression level. The highest level of CAT expression in muscle from a transgenic F1 line was corresponding to 68-fold compared to the basal levels of controls.

• Journal of Plant Biotechnology
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• v.34 no.4
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• pp.375-380
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• 2007

This study was conducted to develop herbicide-resistance domestic maize plants by introducing the CP4 5-enol-pyruvylshikimate-3-phosphate synthase (CP4 EPSPS) gene using Agrobacterium tumefaciens-mediated immature embryo transformation. Immature embryos of five genotypes (HW1, KL103, HW3, HW4, HW7) were co-cultivated with strains Agrobacterium tumefaciens (strain C58C1) containing the binary vector (pCAMBIA2300) carrying Ubiquitin promoter-CP4 EPSPS gene and Cauliflower mosaic virus 35S (CaMV35S) promoter-nptll gene conferring resistance to paromomycin as a selective agent. The presence and expression of CP4 EPSPS transgene were confirmed by PCR, RT-PCR and Northern blot analysis, respectively. Also, the resistance to glyphosate in the transgenic maize ($T_1$) was analyzed by shikimate accumulation assay. The frequency (%) of paromomycin-resistance callus was 0.37, 0.03, 2.20, 2.37, and 0.81% in pure lines HW1, KL103, HW3, HW4 and HW7, respectively. EPSP transgene sequences were amplified in putative transgenic plants that regenerated from paromomycin-resistance calli of two inbred lines (HW3, HW4). Of them, RT-PCR and Northern blot analyses revealed that the transgene was only expressed in two transgenic events (M266, M104) of HW4 inbred line, and a mild glyphosate resistance of transgenic event (M266) was confirmed by the lower shikimate accumulation in leaf segments. These results demonstrate that transgenic maize with herbicide-resistance traits in Korean genotype can be genetically obtained.

• Journal of Plant Biotechnology
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• v.40 no.3
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• pp.135-140
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• 2013

A less simple approach developed for generation of marker-free transgenic plants is to select transformants without the use of selective marker genes. Some results about development of marker-free transgenic plants were obtained using a non-selective approach in several crops such as rice, potato and tobacco. However, the study did not provide evidence on detailed characterization of introduced gene on genome, a critical step for confirming the stable integration and transmission of a foreign gene. In this study, we evaluated structure and integration sites of transgene (mCry1Ac) in the transgenic Bt rice plants which were made via conventional Agrobacterium-mediated transformation by non-selective method. Structure and integration sites of transgene in these transgenic plants had similar fashion as those recovered under selection.

• Korean Journal of Microbiology
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• v.39 no.3
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• pp.128-134
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• 2003

Transformation-associated recombination (TAR) cloning is based on co-penetration into yeast spheroplasts of genomic DNA along with TAR vector DNA that contains 5'- and 3'-sequences (hooks) specific for a gene of interest, followed by recombination between the vector and the human genomic DNA to establish a circular YAC. Typically, the frequency of recombinant insert capture is 0.01-1% for single-copy genes by TAR cloning. To further refine the TAR cloning technology, we determined the effect of GC content on target hooks required for gene isolation utilizing the $Tg\cdot\AC$ mouse transgene as the targeted region. For this purpose, a set of vectors containing a B1 repeated hook and Tg AC-specific hooks of variable GC content (from 18 to 45%) was constructed and checked for efficiency of transgene isolation by radial TAR cloning. Efficiency of cloning decreased approximately 2-fold when the TAR vector contained a hook with a GC content ～${\leq}23$% versus ～40%. Thus, the optimal GC content of hook sequences required for gene isolation by TAR is approximately 40%. We also analyzed how the distribution of high GC content (65%) within the hook affects gene capture, but no dramatic differences for gene capturing were observed.