• Proceedings of the Korean Society of Applied Pharmacology
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• 1996.04a
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• pp.80-104
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• 1996

The development of routine techniques for the isolation and in vitro maintenance of conducting airway epithelial cells in a differentiated state provides an ideal model to study the factors involved in the regulation of the expression of mucocilicary differentiation. Several key factors and conditions have been identified. These factors and conditions include the use of biphasic culture technique to achieve mucociliary differentiation and the use of such stimulators, the thickness of collagen gel substratum, the calcium level, and vitamin A, and such inhibitors, the growth factors EGF and insulin, and steroid hormones, for mucous cell differentiation. Using the defined culture medium, the life cycle of the mucous cell population in vitro was investigated. It was demonstrated that the majority of the mucous cell population in primary cultures is not involved in DNA replication. However, the mucous cell type is capable of self-renewal in culture and this reproduction is vitamin A dependent. furthermore, differentiation from non-mucous cell type to mucous cell type can be demonstrated by adding back a positive regulator such as vitamin A to the “starved” culture. Cell kinetics data suggest that vitamin A-dependent mucous cell differentiation in culture is a DNA replication-independent process and the process is inhibited by TGF-${\beta}$1.

• Journal of Microbiology and Biotechnology
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• v.13 no.3
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• pp.457-462
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• 2003

The complete nucleotide sequence of a plasmid, pMG1, isolated from Bifidobacterium longum MG1 has been determined. This plasmid, composed of 3,862 base pairs with 65.1% of G+C content. harbors two major open reading frames (ORF) encoding putative proteins of 29 kDa (ORF I) and 71 kDa (ORF II). ORF I showed relatively high amino acid sequence homology with replication proteins of other plasmids from Gr Im-positive and -negative bacteria. Upstream of ORF I, four sets of tandem repeat sequences resembling the iteron structure of related plasmids were found. S1 endonuclease treatment and Southern blot analysis revealed that pMG1 accumulates single-stranded DNA (ssDNA) intermediate, which indicate i the rolling circle replication (RCR) mechanism of this plasmid. Homology search indicated that ORF II encodes plasmid mobilization protein, and the presence of highly conserved oriT sequence in the upstream of this gene supported this assumption. RT-PCR showed that only ORF I is expressed in vivo. Based on these results, pMG 1 was exploited to construct a shuttle vector, pBES2. It was successfully transformed into Bifidobacterium and maintained stably.

• YAKHAK HOEJI
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• v.32 no.4
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• pp.239-244
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• 1988

Transcriptional rate of lactate dehydrogenase A-gene(LDH-A) during the prereplicative phase of regenerating rat liver was determined by in vitro run-off transcription assay. The results show that the transcription rate of LDH A-gene increases between 12 hours and 15 hours peaking at 13 hours after partial hepatectomy of rat liver. The increased rate of LDH A-gene transcription was interfered after DL-propranolol treatment intraperitoneally injected twice at 1 hour and 8 hours after partial hepatectomy indicating that the transcriptional control of LDH A-gene expression may be mediated by beta adrenergic receptor and cAMP as a second messenger. And also was it shown that the temporally increased rate of LDH A-gene transcription was maximum one hour after the second cAMP-surge which is known to play an important role for the initiation of DNA replication during regeneration of rat liver. And the transcriptional rate of LDH A-gene was decreased to the basal level at the time period when the hepatocytes proliferate rapidly suggesting that the induced LDH Aisozyme may be required for the initiation of DNA replication during regeneration of rat liver. These data may be supporting for the hypothesis suggesting that the induced LDH A-isozyme during the pre-replicative phase of regenerating rat liver may play bifunctional roles as a glycolytic enzyme and a helix destablizing protein as well.

• BMB Reports
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• v.51 no.6
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• pp.290-295
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• 2018

Y-box binding protein 1 (YB-1) is a member of the cold-shock domain (CSD) protein superfamily. It participates in a wide variety of cellular events, including transcription, RNA splicing, translation, DNA repair, drug resistance, and stress responses. We investigated putative functions of YB-1 in HIV-1 replication. Functional studies using overexpression or knockdown of YB-1 in conjunction with transfection of proviral DNA showed that YB-1 enhances virus production. We found YB-1 regulates HIV-1 production by stimulating viral transcription using HIV-1 LTR sequence U3RU5 with Luciferase assay. We also identified a specific region from amino acids 1 to 324 of YB-1 as necessary for the participation of the protein in the production of virions.

• BMB Reports
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• v.41 no.8
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• pp.581-586
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• 2008

The pre-replication complex (pre-RC), including the core hexameric MCM2-7 complex, ensures that the eukaryotic genome is replicated only once per cell division cycle. In this study, we identified a rice $\underline{m}ini\underline{c}hromosome$ $\underline{m}aintenance$ (MCM) homologue (OsMCM2) that functionally complemented fission yeast MCM2 (CDC19) mutants. We found OsMCM2 transcript expression in roots, leaves, and seeds, although expression levels differed slightly among the organs. Likewise, the OsMCM2 protein was ubiquitously expressed, but it was downregulated when nutritients were limiting, indicating that MCM2 expression (and therefore cell cycle progression) requires adequate nutrition. Yeast two-hybrid and GST pull-down assays demonstrated that OsMCM2 interacted with the COP9 signalosome 5 (CSN5). Taken as a whole, our results indicated that OsMCM2 functions as a subunit of the rice MCM complex and interacts with CSN5 during developmental regulation.

• Microbiology and Biotechnology Letters
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• v.13 no.4
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• pp.345-348
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• 1985

Recombinant chimeric plasmid constructed with Xba I digested pUBl10 and -pE194 was transformed by polyethylene glycol induced protoplast transformation system into Bacillus subtilis BR 151 on the mannitol regeneration media, and two genes of antibiotics resistance were expressed simultaneously in the transfromant. Transformation frequency of the recombinant plasmid was 6.5 $\times$ 10$^{-5}$ on the mannitol regeneration agar plate containing neomycin and erythromycin. The replication of recombinant plasmid in the recipient cells was confirmed by the alkaline extraction method and agarose gel electrophoresis.

• Animal cells and systems
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• v.11 no.2
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• pp.129-134
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• 2007

The initiation of eukaryotic DNA replication requires assembly of the pre-replicative complex (Pre-RC) through the concerted action of Orc, Cdc6, Cdt1 and Mcm2-7 complex during G1 phase. The pre-RC assembly licenses individual replication origins for the initiation of DNA replication and sufficient number of the pre-RC is essential for proper progression of S phase. However, it is not well known how cells recognize the completion of the pre-RC assembly before G1-S transition. In order to understand the cellular responses to the defects in pre-RC assembly, we depleted the known components of pre-RC proteins using the small interference RNAs in HeLa cells. Although the defects of pre-RC assembly by the depletion of the pre-RC proteins such as Orc2, Cdt1, Mcm2 & Mcm10 did not elicit the activation of Chk1- or Chk2-dependent checkpoint pathways, these cells still showed significant decrease in the cellular level of Cdc25A proteins. These results suggests that a novel checkpoint pathway exist in HeLa cells, which is not dependent upon Chk1 or Chk2 proteins and play essential roles in the cellular responses to the defects in the pre-RC assembly. Also, among those four proteins tested in this study, the depletion of Mcm10 and Cdt1 proteins significantly increased the apoptotic cell death in HeLa cells, suggesting that these proteins not only play roles in the pre-RC assembly, but also are involved in the checkpoint responses to the defects in the pre-RC assembly.

• BMB Reports
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• v.42 no.1
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• pp.22-27
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• 2009

Replication Protein A (RPA) is a single stranded DNA-binding protein involved in DNA metabolic activities such as replication, repair, and recombination. RPA-Interacting Protein $\alpha$ ($RIP{\alpha}$) was originally identified as a nuclear transporter of RPA in Xenopus. The human $RIP{\alpha}$ gene encodes several splice isoforms, of which $hRIP{\alpha}$ and $hRIP{\beta}$ are the major translation products in vivo. However, limited information is available about the alternative splicing of $RIP{\alpha}$ in eukaryotes, apart from that in humans. In this study, we examined the alternative splicing of RIP{\alpha} in the Drosophila, Xenopus, and mouse system. We showed that the number of splice isoforms of RIP{\alpha} was species-specific, and displayed a tendency to increase in higher eukaryotes. Moreover, a mouse ortholog of $hRIP{\alpha}$, $mRIP{\beta}2$, was not SUMOylated, in contrast to $hRIP{\alpha}$. Based on these results, we suggest that the $RIP{\alpha}$ gene gains more splice isoforms and additional modifications after molecular evolution.

• The Journal of Korean Medicine
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• v.19 no.2
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• pp.244-270
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• 1998

This study was performed to investigate an anti-HBV activities of the aqueous extracts from 10 Korean herbal medicines in the HepG2 2.2.15 cell culture system and the results were as follows: 1. The extracts of 6 plants (Herba Artemisiae Capillaris, Radix et Rhizoma Rhei, Cortex Cinnamomi, Fructus Chebulae, Fructus Rubi and Radix Rubi) decreased, significantly and dose-dependently, the levels of extracellular HBV virion in the concentrations (10, 100, 500 and $1,000\;{\mu}g/m{\ell}$) tested. 2. However, others (Radix lsatidis, Lignum Sappan, Herba Lysimachiae and Fructus Lycii) did not show any effect either on the replication of HBV or on the levels of virion DNA in the culture media of HepG2 2.2.15 cell. 3. Among the 6 plants which showed the inhibitory potency on the production of extracellular HBV virion, Radix et Rhizoma Rhei, Cortex Cinnamomi, Fructus Chebulae, Fructus Rubi and Radix Rubi except Herba Artemisiae Capillaris also showed the inhibition of the replication of intracellular HEV DNA in the range of $100{\sim}500\;{\mu}g/m{\ell}$. Considering the above results, it is thought that 6 plants(Herba Artemisiae Capillaris, Radix et Rhizoma Rhei, Cortex Cinnamomi, Fructus Chebulae, Fructus Rubi and Radix Rubi) possess the anti-HBV activities in the HepG2 2.2.15 cell culture system. We thus suggest that these plants possess a potential as a therapeutic agent for the chronic viral hepatitis. These results might be useful as a basic data for the development of the new preventive drugs for HBV diseases.

• Microbiology and Biotechnology Letters
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• v.19 no.3
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• pp.215-221
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• 1991

An autonomous replication sequence (ARS) derived from Cephalosporium acremonium ATCC 20339 was cloned in Sarchuromyces cerevisiae SHY 3 using YIp5 as a cloning vector. A new recombinant plasmid, designated pCY-2, which contained a 3.7 kb BamHI fragment of C. acrenzonium DNA showed the highest stability among the 40 recombinant plasmids composed of the YIp5 2nd ARS of C. ucremoniztm. Also, Southern hybridization and transformation of E, cull with DNA purified from yeast transformants verified that pCY-2 autonomously replicates in yeasts. Transformation efficiency and plasmid stability of pCY-2 in yeast were higher than those ol YRp 7 containing ARS which originated from yeast. Detailed studies by subcloning revealed that two ARSs existed within 2.6 kb of the insert, which is a novel discovery. However, it was concluded that these two ARSs were ligated during the gene manipulation in vitro.