• Journal of Plant Biotechnology
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• v.33 no.1
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• pp.19-25
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• 2006

With the use of Agrobacterium and gene-gun, cold regulated gene (BN115) has been injected in Chrysanthemum leaf disc and transgenic plants have been produced successfully on the selection media containing phytohormone. To determine the presence of the transferred cold regulated gene (BN115) in the transgenic Chrysanthemum, PCR-amplification indicated the presence of that gene. Real-Time PCR for confirmation of the putative transgenic plants was established. The copy number of cold regulated gene (BN115) is extrapolated on the basis of a standard curve. Serial dilutions of known number of gene copies were in triplicates. In this diagram, PCR cycles are plotted against the fluorescence intensity. The cycle at which the fluorescence reaches a threshold cycle is inversely proportional to the starting amount of target DNA.

• Polymer(Korea)
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• v.30 no.4
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• pp.279-285
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• 2006

Non-viral gene carriers continue to attract a great deal of interest due to advantageous safety profile. Among the non-viral gene carriers, cationic liposomes or synthetic gene carriers are efficient DNA carriers in vitro. but their in vivo applications are greatly hampered because of low biocompatibility. On the other hand, chitosan, a natural cationic polysaccharide, is a candidate non-viral vector for gene delivery because of its low cytotoxicity and high positive charges. In this work, targeted gene carrier was synthesized to target artery wall cells using low molecular water-soluble chitosan (LMWSC). The molecular weight $(M_W)$ and degree of de acetylation (DDA) of LMWSC were measured by relative viscometer and Kina titration. respectively. The structure of LMWSC was analyzed by measuring FTIR, $^1H-NMR,\;and\;^{13}C-NMR$. AWBP-PEG-g-LMWSC was synthesized by conjugation of the artery wall binding peptide (AWBP), a specific targeting peptide, to the end of pegylated LMWSC as a gene carrier to target artery wall cells. The synthesized AWBP-PEG-g-LMWSC were analyzed by measuring FTIR, $^1H-NMR$, zeta -potentiometer, and atomic force microscopy (AFM).

• The Korean Journal of Pesticide Science
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• v.12 no.3
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• pp.283-290
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• 2008

Baculoviruses have been used to control some serious lepidopteran pests. However, their narrow target insect spectrum and slow efficacy are main limitations to be used in various applications. This study introduces a technique to overcome these limitations by inhibiting insect immune defence to enhance the viral pathogenicity. Polydnaviruses are an insect DNA virus group and symbiotic to some ichneumonid and braconid endoparasitoids. Cotesia plutellae bracovirus (CpBV) is a braconid polydnavirus and encodes several immunosuppressive genes. We selected seven CpBV genes and recombined them to wild type Autographa California multiple nucleopolyhedrovirus (AcNPV). A bioassay of these seven recombinants indicated that most recombinants had similar or superior efficacy to wild type AcNPV against beet armyworm, Spodoptera exigua, and diamondback moth, Plutella xylostella. Recombinant AcNPV with CpBV-ELP was the most potent in terms of lethal time by shortening more than 2 days compared to wild type AcNPV. This recombinant was further proved in its dose-dependent pathogenicity and its efficacy by spray application on S. exigua infesting cabbage cultivated in pots. We discussed the efficacy of CpBV-ELP recombinant AcNPV in terms of suppressing antiviral activity of target insects.

• Korean Journal of Microbiology
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• v.48 no.2
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• pp.79-86
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• 2012

ErmSF is one of the Erm family proteins which catalyze S-adenosyl-$_L$-methionine dependent modification of a specific adenine residue (A2058, E. coli numbering) in bacterial 23S rRNA, thereby conferring resistance to clinically important macrolide, lincosamide and streptogramin B ($MLS_B$) antibiotics. $^{222}FXPXPXVXS^{230}$ (ErmSF numbering) sequence appears to be a consensus sequence among the Erm family. This sequence was supposed to be involved in direct interaction with the target adenine from the structural studies of Erm protein ErmC'. But in DNA methyltarnsferase M. Taq I, this interaction have been identified biochemically and from the complex structure with substrate. Arginine 223 and 227 in this sequence are not conserved among Erm proteins, but because of the basic nature of residues, it was expected to interact with RNA substrates. Two amino acid residues were replaced with Ala by site-directed mutagenesis. Two mutant proteins still maintained its activity in vivo and resistant to the antibiotic erythromycin. Compared to the wild-type ErmSF, R223A and R227A proteins retained about 50% and 88% of activity in vitro, respectively. Even though those arginine residues are not essential in the catalytic step, with their positive charge they may play an important role for RNA binding.

• Journal of Life Science
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• v.28 no.4
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• pp.488-495
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• 2018

The p53 gene plays a critical role in the transcriptional regulation of cellular response to stress, DNA damage, hypoxia, and tumor development. Keeping in mind the recently discovered manifold physiological functions of p53, its involvement in the regulation of cancer is not surprising. In about 50% of all human cancers, inactivation of p53's protein function occurs either through mutations in the gene itself or defects in the mechanisms that activate it. This disorder plays a crucial role in tumor evolution by allowing the evasion of a p53-dependent response. Many recent studies have focused on directly targeting p53 mutants by identifying selective, small molecular compounds to deplete them or to restore their tumor-suppressive function. These small molecules should effectively regulate various interactions while maintaining good drug-like properties. Among them, the discovery of the key p53-negative regulator, MDM2, has led to the design of new small molecule inhibitors that block the interaction between p53 and MDM2. Some of these small molecule compounds have now moved from proof-of-concept studies into clinical trials, with prospects for further, more personalized anti-carcinogenic medicines. Here, we review the structural and functional consequences of wild type and mutant p53 as well as the development of therapeutic agents that directly target this gene, and compounds that inhibit the interaction between it and MDM2.

• Journal of Plant Biotechnology
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• v.37 no.1
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• pp.77-83
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• 2010

Eighteen cultivars of tomato were tested for their regeneration response. Lycopersicon esculentum cv. 2001-58 showed a very high frequency of regeneration (93%). We evaluated the effect of two compounds with known antioxidant activity (ascorbic acid and cystein). The use of ascorbic acid ($200\;-\;300\;{\mu}M/L$) has a positive effect on shoot regeneration. To develope a system for plastid transformation in tomato via homologous recombination, we constructed the tomato plastid expression vector (pKRT22-AG) harboring 2.2 kb flanking sequences cloned from intact plastid genome and gfp gene. To investigate the factors affecting the delivery system of the pKRT22-AG into chloroplast using bombardment, We assessed the optimal DNA concentration, gold particle volume and target distance. Expression of the GFP protein was observed within chloroplast on protoplast of cotyledon explant by confocal laser scanning microscopy, which indicates that the protocol developed in this study be useful for the production of plastid transgenic plants in tomato.

• Journal of Life Science
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• v.25 no.5
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• pp.585-593
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• 2015

Stress fiber (SF) alteration is mediated by cellular receptors, which, upon interaction with the extracellular counterpart, signal to the actin cytoskeleton for remodeling. This association is mediated by a variety of scaffold and signaling factors, which control the mechanical and signaling activities of the interaction site. The heterotrimeric transmembrane lymphotoxin α1β2 (LTα1β2), a member of the tumor necrosis factor (TNF) family of cytokines, including soluble homotrimeric lymphotoxin (LT α), plays an important role in lymphoid tissue architecture. Ligation between LTα1β2 and the lymphotoxin β receptor (LTβR) activates signal-cascade in fibroblastic reticular cells (FRCs). We found LTβR stimulation using an agonistic anti-LTβR antibody alone or combined with LTα or TNFα induced changes in the actin and plasticity of cells. To clarify the involvement of myosin underlying the alteration, we analyzed the effect of myosin light chain kinase (MLCK) with an MLCK inhibitor (ML7), the phosphorylation level of myosin light chains (MLC), and the level of phospho-myosin phosphatase target subunit 1 (MYPT1) after treatment with an agonistic anti-LTβR antibody for cytoskeleton reorganization in FRCs. The inhibition of MLCK activity induced changes in the actin cytoskeleton organization and cell morphology in FRC. In addition, we showed the phosphorylation of MLC and MYPT1 was reduced by LTβR stimulation in cells. A DNA chip revealed the LTβR stimulation of FRC down-regulated transcripts of myosin and actin components. Collectively, these results suggest LTβR stimulation is linked to myosin regarding SF alteration in FRC.

• Proceedings of the Korean Society for Bioinformatics Conference
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• 2006.02a
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• pp.83-89
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• 2006

Cellular functions are carried out by a concerted action of biochemical pathways whose components have genetic interactions. Abnormalities in the activity of the genes that constitute or modulate these pathways frequently have oncogenic implications. Therefore, identifying the upstream regulatory genes for major biochemical pathways and defining their roles in carcinogenesis can have important consequences in establishing an effective target-oriented antitumor strategy We have analyzed the gene expression profiles of human liver cancer samples using cDNA microarray chips enriched in liver and/or stomach-expressed cDNA elements, and identified groups of genes that can tell tumors from non-tumors or normal liver, or classify tumors according to clinical parameters such as tumor grade, age, and inflammation grade. We also set up a high-throughput cell-based assay system (cell chip) that can monitor the activity of major biochemical pathways through a reporter assay. Then, we applied the cell chip platform for the analysis of the HCC-associated genes discovered from transcriptome profiling, and found a number of cancer marker genes having a potential of modulating the activity of cancer-related biochemical pathways such as E2F, TCF, p53, Stat, Smad, AP-1, c-Myc, HIF and NF-kB. Some of these marker genes were previously blown to modulate these pathways, while most of the others not. Upon a fast-track phenotype analysis, a subset of the genes showed increased colony forming abilities in soft agar and altered cell morphology or adherence characteristics in the presence of purified matrix proteins. We are currently analyzing these selected marker genes in more detail for their effects on various biological Processes and for Possible clinical roles in liver cancer development.

• Korean Journal of Veterinary Service
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• v.34 no.4
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• pp.417-428
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• 2011

Species-specific PCR assay was developed for detection of cattle, sheep, goat, horse, dog, pig, chicken, duck, goose, and turkey using mitochondrial 12S rRNA and 16S rRNA as target genes. Also, an internal positive control was used to detect possible false negatives by using 18S rRNA gene. We designed species-specific primers with amplicon length of 190, 219, 350, 467, 241, 119, 171, 229, 111 and 268 bp for cattle, sheep, goat, horse, dog, pig, chicken, duck, goose, and turkey respectively. The specificity of the primers was tested against the other 10 non-target animal species and a cross-reaction was not observed. We developed two multiplex PCR assays for the simultaneous identification of Korea's major livestock species (cattle, pig, chicken and duck) and poultry species (chicken, duck, goose and turkey) from analogous samples, retaining the same specificity. The limit of detection of the multiplex PCR assay (cattle, pig, chicken and duck) ranged between 1 pg and 0.1 pg of template DNA extracts from raw meat. Applying multiplex PCR assays to DNA extracts from experimental pork/beef and pork/chicken tested raw and heat-treated ($120^{\circ}C$ for 30 min) mixtures respectively, detection limit was 0.1% level beef in pork, pork in beef and chicken in pork and 1.0% level pork in chicken. In conclusion, this assay using gel-based capillary electrophoresis would be very useful in highly sensitive and rapid identification of animal species or ingredients in minced meat and other meat products.

• Korean Journal of Breeding Science
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• v.49 no.3
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• pp.170-179
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• 2017

Plant molecular farming has attracted a lot of attention lately in the field of mass production of industrially valuable materials by extending application of the plant as a kind of factory concept. Among them, protein expression system using rice(Oryza sativa L.) callus is a technology capable of mass culture and industrialization because of a high expression rate of a target protein. This study was carried out to develop an Agrobacterium-mediated transformation system to increase the utilization of rice callus. The transformation efficiency was improved by using the hand when seeds were de-husked for callus induction. Furthermore, we were possible induction of callus from 6 years old seed smoothly. Selection of the callus contained the target gene was required a cultivation period of at least 3 weeks, and the most efficient selection period was after 6 weeks of culture including one passage. This selection was confirmed that the gene was stably inserted into the genomic DNA of the plant cell by the southern blot analysis and progeny test. Such an efficient selection system of rice callus that can be cultured in the long term will be contribute to the industrialization of useful recombinant proteins using rice.