• Journal of Life Science
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• v.18 no.1
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• pp.114-119
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• 2008

The molecular machinery controlling cell cycle is centered around the regulation of the activity of maturation-promoting factor (MPF), a complex composed of a catalytic Cdc2 and the cyclinB regulatory subunit. Cdc2 kinase is inactivated by phosphorylation of inhibitory kinase, Wee1. It has been known that there are three different Wee1 kinases in the mammalian cell, Wee1A, Wee1B and Myt1. To investigate the regulatory mechanism of Wee1 kinases, the phosphorylation and degradation of Wee1A and Wee1B were checked in the Xenopus oocyte cell cycle. When Wee1 kinases were injected into frog oocyte, Wee1B was more stable than Wee1A. Wee1A and Wee1B kinase were phosphorylated by many kinases such as PKA and Akt. The roles of amino or carboxyl terminal in mouse Wee1A or Wee1B kinase were investigated using chimeric constructs. The degree of protein phosphorylation, degradation and cell cycle progression were different between chimeric constructs. The amino domain of Wee1A was implicated in the protein phosphorylation and degradation while amino domain of Wee1B and carboxyl domain of Wee1A were involved in the activity regulation. These results suggested that the domains of Wee1 kinase have different and significant roles in regulating the Wee1 kinases in the cell cycle progression.

• Applied Biological Chemistry
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• v.39 no.5
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• pp.355-360
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• 1996

In vitro-tested ribozyme against synthesized cucumber mosaic virus (CMV) RNA (Agric. Chem. & Biotech. 37:56-63(1994)) was expressed in tobacco plant to develop virus resistant plants. The ribozyme sequence was linked to cauliflower mosaic virus 35S promoter and nopaline synthase(nos) terminator and this chimeric 35S-ribozyme-nos gene was sequenced. The sequenced chimeric gene was transferred to Agrobacterium tumefaciens LBA4404 using tri-parental mating system. The E. coli HB101 containing chimeric gene was incubated with E. coli HB101(pRK2073) as a helper and Agrobacterium tumefaciens LBA4404. Then Agrobacterium cells containing the ribozyme construct was cocultivated with tobacco leaf pieces. Ten different plants were regenerated from kanamycin containing MS medium. The presence of the ribozyme construct in the transgenic tobacco plants was confirmed by polymerase chain reaction (PCR). Seven different transgenic plants in ten different kanamycin resistant plants showed the expected size (570 base pairs) of 35S-ribozyme-nos gene fragment. Total RNAs were isolated from four different transgenic plants and separated on a 1% agarose gel containing formamide. Northern hybridization with 35S-ribozyme-nos gene fragment as a probe indicated that ribozyme transcripts may be degraded tv nuclease. Therefore, nuclease-resistant ribozymes are needed for the development of virus-resistant transgenic plants using ribozymes.

• Proceedings of the Microbiological Society of Korea Conference
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• 2005.05a
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• pp.208.3-208
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• 2005

• Proceedings of the Korean Society for Applied Microbiology Conference
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• 1986.12a
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• pp.524.1-524
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• 1986

CMCase, a member of cellulose decomposing enzymes, hydrolyze cellulose up to cellobiose. Cellobiase splits cellobiose to glucose units. Therefore, a linkage of the twogenes coding for CMCase and cellobiase on the same plasmid is needed to produce a cellulase complex which can produce glucose from cellulose. A genetic operon in which the two structural genes are under the control of a single promoter would be ideal for this purpose. The present report is on the linking of the two cellulase genes in one plasmid as a preliminary step of the operon construction.

• Proceedings of the PSK Conference
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• 2002.10a
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• pp.149-150
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• 2002

Despite various efforts on improving vaccines and antivirals, influenza epidemics continue to afflict many people, causing widespread morbidity and mortality in the young and the elderly. Since the discovery of the unusual 'cap-stealing'mechanism of transcription, significant advances were made on molecular aspects of influenza gene regulation. This provides new insights for developing new antiviral compounds. Reverse genetic technologies have also been advanced for generating recombinant chimeric viruses suitable for designing live vaccine. (omitted)

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2002.11a
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• pp.47.1-47
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• 2002

• Archives of Plastic Surgery
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• v.42 no.6
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• pp.810-813
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• 2015

• Journal of Plant Biotechnology
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• v.6 no.1
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• pp.15-19
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• 2004

The expression of a chimeric transgene (nos-npt II) has been examined in 9 years old transgenic poplars (Populus koreana x P. nigra) growing in a nursery. The expression of the gene in twenty six independentely transformed plants were examined by 1) enzyme (NPT II) assay, 2) RT-PCR, and 3) resistance to kanamycin. High NPT II activities in young leaves of all the transformed plants were found even without a selection pressure for antibiotics for 9 years. However, the activity varied with the positions of leaves in the stem in that young leaves showed higher activity than did mature tissues. When leaf segments were cultured in the presence of 150 mg/l kanamycin, only those from young leaves produced vigorously growing callus. However, as in the case of NPTII assay, the leaf segments from mature leaves did not form callus well on the media. RT-PCR with nptII specific primers also showed that amplification products were observed only when RNAs from young tissues were used. The total RNA gel showed that while RNA in young leaves are relatively stable and in a large quantity, those in old leaves were mostly degraded. All the above results suggest that the gene is transcriptionally active only in young tissue even though it is attached to a constituitive promoter. Therefore, the expression of foreign gene in poplar plants seemed to be affected by the metabolic state of the cells and thus vary greatly with the developmental stages and the age of tissue.

• Archives of Pharmacal Research
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• v.20 no.5
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• pp.454-458
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• 1997

Two human liver UDP-glucuronosyltransferase cDNA clones, HLUG25 and UDPGTh2 were previously shown to encode isozymes active in the glucuronidation of hyodeoxycholic acid (HDCA) and certain estrogen derivatives (e.g., estriol and 3,4-catechol estrogens), respectively. in this study we have found that the UDPGTh2-encoded isoform (UDPGTh2) and HLUG25-encoded isoform (UDPGThl) have parallel aglycone specificities. When expressed in COS 1 cells, each isoform metabolized three types of dihydroxy- or trihydroxy-substituted ring structures, including the 3,4-catechol estrogen (4-hydroxyestrone), estriol, 17-epiestriol, and HDCA, but the UDPGTh2 isozyme was 100-fold more efficient than UDPGTh1. UDPGTh1 and UDPGTh2 were 86% identical overall (76 differences out of 528 amino acids), including 55 differences in the first 300 amino acids of the amino terminus, a domain which conferred the substrate specificity. The data indicated that a high level of conservation in the amino terminus was not required for the preservation of substrate selectivity. Analysis of glucuronidation activity encoded by UDPGTh1/UDPGTh2 chimeric cDNA constructed at their common restriction sites, Sac I (codon 297), Nco I (codon 385), and Hha I (codon 469), showed that nine amino acids between residues 385 and 469 were important for catalytic efficiency, suggesting that this region represented a domain which was critical for the catalysis but distinct from that responsible for aglycone-selection. These data indicate that UDPGTh2 is a primary isoform responsible for the detoxification of the bile salt intermediate as well as the active estrogen intermediates.

• Journal of Microbiology and Biotechnology
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• v.14 no.5
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• pp.1031-1037
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• 2004

The interaction of chemoattractant receptors and $G{\alpha}_{16}$ was studied to provide the molecular basis to elucidate the interaction of chemoattractant receptors with $G{\alpha}_{16}$ subunit, thereby possibly contributing to finding novel targets for designing new type of G protein antagonists with anti-inflammatory effects. Experiments were performed to characterize the $G{\alpha}_{16}$ subunit domains responsible for efficient coupling to chemoattractant receptors. Thus, a series of chimeric $G{\alpha}_{11}G{\alpha}_{16}$ and $G{\alpha}_{16}G{\alpha}_{11}$ cDNA constructs were expressed, and the ability of chimeric proteins to mediate C5a, IL-8, and fMLP-induced release of inositol phosphate in transfected Cos-7 cells was tested. The results showed that short stretches of residues 154 to residue 167 and from residue 174 to residue 195 of $G{\alpha}_{16}$ contribute to efficient coupling to the C5a receptor. On the other hand, a stretch of amino acid residues 220-240 of $G{\alpha}_{16}$ that is necessary for interacting with C5a receptor did not play any role in the interaction with IL-8 receptor. However, a stretch from residue 155 to residue 195 of $G{\alpha}_{16}$ was found to be crucial for efficient coupling to IL-8 receptor in concert with C-terminal 30 amino acid residues of this ${\alpha}$ subunit. Coupling profiles of a variety of chimeras, composed of $G{\alpha}_{11}G{\alpha}_{16}$ to fMLP receptor indicate that the C-terminal 30 amino acids are most critical for the coupling of $G{\alpha}_{16}$ to fMLP receptor. Taken together, $G{\alpha}_{16}$ subunit recruits multiple and distinctive coupling regions, depending on the type of receptors, to interact.