• Applied Biological Chemistry
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• 제38권2호
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• pp.118-122
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• 1995

Escherichia coli의 오르니틴 트란스카바밀라제는 오르니틴과 카바밀인산으로부터 시트룰린의 합성을 촉진시키는 효소이다. 이 효소의 기능과 구조와의 상관관계, 반응메카니즘 등 생화학적 연구를 하기 위하여 대량의 효소를 추출할 필요가 있다. 본 연구는 오르니틴 트란스카바밀라제의 대량생산 시스템을 확립하기 위하여 E. coli argI 유전자를 E. coli $DH5{\alpha}$ 세포의 염색체 DNA를 추출한 후에 PCR 방법으로 증폭시켜 얻었다. 증폭된 argI 유전자를 단핵생물 단백질 발현벡터인 pKK223-3에 접합시킨 후, 오르니틴 트란스카바밀라제가 존재하지 않은 E. coli TB2 세포에 클로닝 시켰다. 이 세포로부터 생산된 오르니틴 트란스카바밀라제는 암모늄염에 의한 분할, 열변성, 크로마토그래피 등을 사용하여 순수하게 분리하였다. SDS 단백질 전기영동 결과 약 38 kDa 크기의 효소가 순수하게 얻어졌다. 반응속도론적 실험결과 $K_{cat}$은 $1{\times}10^5m^{-1}$, $K_M$은 오르니틴에 대하여는 0.35 mM, 카바밀인산에 관하여는 0.06 mM이 각각 얻어졌다. 이 결과는 야생형 오르니틴 트란스카바밀라제의 반응속도 인자들과 비슷한 값이다. 본 연구는 이들 결과로부터 오르니틴 트란스카바밀라제의 기능을 하는 E. coli argI 유전자가 클로닝 되었음을 확인하였다.

• 대한한방내과학회지
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• 제20권1호
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• pp.99-110
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• 1999

Effects of Chiyangtang(CYT) on H. pylori-induced increase of interleukin 8 and interleukin 1 gene expression was studied in Kato Ⅲ cell line, a human stomach epithelial cell line. Treatment of H. pylori to the cell culture signifant!y increased IL-8 and IL-1 mRNA synthesis. When CYT was added along with H. pylori, the increase of IL-8 and IL-1 mRNA synthesis was blocked. Activation of transcription factor $NF-{\kappa}B$ and AP-1 which were known to important in IL-8 and IL-1 gene expression was also studied using chloramphenicol acetyltransferase(CAT) assay. Treatment of H. pylori increased activation of $NF-{\kappa}B$ and AP-l and CYT effectively protected the activation. Electrophoretic mobility shift assay suggested that CYT effectively inhibited DNA binding of $NF-{\kappa}B$ and AP-l to their cognate site. These results suggested that CYT could prevent stomach diseases through the down regulation of IL -8 and IL-l gene expression which might be mediated by the inhibition of $NF-{\kappa}B$ and AP-1 activities and their binding to DNA.

• 한국식품영양과학회지
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• 제45권4호
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• pp.510-517
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• 2016

본 연구는 싸리나무 잎에서 분리한 flavonoid 화합물인 eriodictyol의 항산화 활성을 평가하기 위해 hydrogen peroxide로 산화적 스트레스를 유도한 HepG2 세포에서 eriodictyol 화합물의 처리가 SOD-1, SOD-2, CAT 및 GPx의 유전자 발현에 미치는 영향을 분석하였으며, 또한 간 기능 지표효소인 GOT, LDH 및 GGT 활성을 분석하였다. 그리고 세포 내 활성산소종 생성 억제 효능을 분석하기 위하여 DCFH-DA assay를 실시하여 eriodictyol 화합물의 기능성 소재로서의 가능성을 알아보고자 본 실험을 하였다. Eriodictyol 화합물의 세포독성을 확인하기 위하여 HepG2 세포주를 이용하여 실시한 결과 eriodictyol 화합물을 $10{\sim}50{\mu}g/mL$의 농도로 처리한 모든 실험군에서 약 98% 이상의 세포생존율을 나타내었다. 항산화 효소 유전자 발현량을 통한 산화스트레스 억제 효과를 분석하기 위하여 HepG2 세포주에 hydrogen peroxide를 처리하여 산화스트레스가 증가시킨 조건에서 eriodictyol 화합물을 처리하여 SOD-1, SOD-2, CAT 및 GPx 발현량을 분석한 결과 eriodictyol 화합물의 처리 농도가 증가할수록 hydrogen peroxide 처리에 의해 감소한 SOD-1, SOD-2, CAT 및 GPx 발현량이 유의적으로 증가하는 것을 확인할 수 있었다. 간 기능 지표효소 활성을 측정하기 위해 GOT, LDH 및 GGT 활성을 분석한 결과 hydrogen peroxide로 단독 처리한 대조군과 eriodictyol 화합물을 처리한 군을 비교하였을 때 eriodictyol 화합물을 처리한 군에서 hydrogen peroxide 처리에 의해 증가한 GOT, LDH 및 GGT 활성이 유의적으로 감소하였다. HepG2 세포주에 eriodictyol 화합물을 처리하여 세포 내 활성산소종 생성에 미치는 영향을 DCFH-DA assay로 확인한 결과 eriodictyol 화합물의 농도가 증가함에 따라 세포내 활성산소종의 생성을 억제하는 것을 확인할 수 있었다. 따라서 본 실험을 통하여 eriodictyol 화합물은 산화적 스트레스로부터 항산화 효소 활성을 증가시키며, 활성산소종의 생성을 억제하는 효과를 확인할 수 있었다. 또한 간 기능 지표효소의 활성을 감소시켜 세포 보호 효과를 나타내어 항산화 활성 및 세포 보호 효과를 나타내는 기능성 소재로써 이용 가능성이 높을 것으로 판단되며, 후속연구를 통해 싸리나무 유래 eriodictyol 화합물의 세포 내 항산화 단백질 발현에 미치는 영향 및 동물실험을 통한 항산화 효과를 검증하는 것이 필요할 것으로 생각된다.

• BMB Reports
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• 제30권5호
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• pp.342-345
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• 1997

Catechol 1,2-dioxygenase $I_1$ (CD $I_1$) gene of Acinetobacter Iwoffii K24, $catA_1$ was expressed in Escherichia coli and was partially purified by using a MonoQ column. Expressed CD $I_1$ had the same molecular weight as purified CD $I_1$ from A. Iwoffii K24 on SDS-PAGE. Expressed CD $I_1$ was also identified by Western blotting and peptide sequencing of N-terminal and internal regions. When compared with purified CD $I_1$ of A. Iwoffii K24, expressed CD $I_1$ had similar substrate specificities and the effects of compounds on enzyme activity. N-terminal amino acid sequence of CD I expressed in E. coli was the same as that of purified CD $I_1$, suggesting that CD $I_1$ may be under the same posttranslational processing in E. coli and A. Iwoffii K24.

• Toxicological Research
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• 제16권2호
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• pp.95-100
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• 2000

In previous study, both constitutive expression and 3-methylcholanthrene (3MC)-mediated elevation of CYP1A2 mRNA were demonstrated in human hepatoma HepG2 cells by reverse transcription-polymerase chain reaction (RT-PCR), suggesting that HepG2 cells would be appropriate for the study of human CYP1A2 regulation(Chung and Bresnick, 1994). Further studies were conducted to determine the basis of this induction phenomenon that is observed in HepG2 cells. Since CYP1A1 gene, another polycyclic hydrocarbon(PH)-inducible gene, is regulated by PHs through their interactions via receptors with cis-elements, the 5'-flanking region of human CYP 1A2 gene was analyzed to search such responsive elements. The promoter activity of various lengths of CYP1A2 gene sequence (-3203/+58bp) was measured in transiently-transfected HepG2 cells by fusion constructs containing the CAT, hGH or luciferase genes as a reporter. This region of the CYP1A2 gene, although containing a XRE, was only weakly responsive (less than 2 fold induction) to 10 nM of TCDD or 1 $\mu$M 3 MC treatment. This small enhancement of promoter activity is inconsistent with the previous observation, i.e., 12 to 14 fold-enhanced CYP1A2 mRNA from 1 $\mu$M 3 MC treated HepG2 cells, suggesting that additional mechanisms would exist for PH-mediated induction of CYP1A2 in these cells.

• Animal cells and systems
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• 제1권1호
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• pp.151-155
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• 1997

Promoter of the Drosophila proliferating cell nuclear antigen (PCNA) gene contains DRE (Drosophila DNA replication-related element) required for the high level expression of replication-related genes. Recently, we found that promoter region of the D-raf (a Drosophila homolog of the human c-raf-1) contains two sequences homologous to the DRE and demonstrated the DRE/DREF (DRE-binding factor) involvement in regulation of the D-raf gene. In this study, using ursolic acid (UA), a pentacyclic triterpene acid reported to possess antitumor activities, we examined effects of UA on proliferation of the Drosophila cultured Kc cells and on expression of the PCNA and D-raf genes. UA showed an inhibitory effect on proliferation of the Kc cells in a concentration-dependent manner in DNA content assays and [3H]thymidine incorporation assays. The IC50 value of anti-proliferative effects of UA in DNA content assays was about 7.5uM. UA showed inhibitory effects on expression of the PCNA as well as on that of the D-raf, which were examined with the reporter plasmic p5'-168DPCNACAT or p5'-878DrafCAT, respectively. The results obtained in the present study suggest that expression of the PCNA and D-raf genes is coordinately regulated in at least UA-treated Kc cells and that down-regulation of expression of the PCNA and D-raf genes might be related with the antitumor activities of UA.

• Journal of Microbiology and Biotechnology
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• 제17권8호
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• pp.1353-1360
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• 2007

Three csp-like genes were identified in the Corynebacterium glutamicum genome and designated cspA, cspB, and cspA2. The genes cspA and cspA2 encode proteins, comprising of 67 amino acid residues, respectively. They share 83% identity with each other. Identity of those proteins with Escherichia coli Csp proteins was near 50%. The cspB gene encodes a protein composed of 127 amino acids, which has 40% and 35% sequence identity with CspA and CspA2, respectively, especially at its N-terminal region. Analysis of the gene expression profiles was done using transcriptional cat fusion, which identified not only active expression of the three genes at the physiological growth temperature of $30^{\circ}C$ but also growth phase-dependent expression with the highest activity at late log phase. The promoters of cspA and cspA2 were more active than that of cspB. The expression of the two genes increased by 30% after a temperature downshift to $15^{\circ}C$, and such stimulation was more evident in the late growth phase. In addition, the cspA gene appeared to show DNA-binding activity in vivo, and the activity increased at lower temperatures. Interestingly, the presence of cspA in multicopy hindered the growth of the host C. glutamicum cells at $20^{\circ}C$, but not at $30^{\circ}C$. Altogether, these data suggest that cspA, cspB, and cspA2 perform functions related to cold shock as well as normal cellular physiology. Moreover, CspA and its ortholog CspA2 may perform additional functions as a transcriptional regulator.

• 미생물학회지
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• 제21권2호
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• pp.61-70
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• 1983

Synchronized cat kidney cells chronically infected with feline leukemia virus (FeLV) were used to study virus production, the synthesis of group specific antigen (gag) and envelope (env) proteins, the expression of env protein on the cell surface during the cell cycle, and the stability of viral RNA. As detecting method, we developed the radioimmunoassay (RIA) system using beta-emission of $^{131}I$ and demonstrated the validity of this system by comparison with routine RIA system using gamma-emission of $^{125}I$. The produced virus was analysed by developed RIA interval was determined by measuring reverse transcriptase activity. The results show that infected cells produce the complete virus particle containing products of gag, env and pol genes of FeLV, and maximum virus production occurs during mitosis of synchronized cells. Labeling of the cell surface of synchronized cells with $^{131}I$ shows that the amount of $gp70^{env}$ on the cell surface parallels cellular gorwth. Therefore, the cell cycle-dependent release of virus is not petition RIA of synchronized cells with $^{131}I$ labeled viral proteins synthesis during the cell cycle. The rate of synthesis of gag protein shows three peaks, corresponding to the $G_1,\;late\;S\;and\;late\;G_2$ phases of cell cycle. But the rate of synthesis of env protein dose not change, suggesting that in these cells the synthesis of these two gene products in controlled seperately. In Actionomycin D treated cells, the synthesis of viral proteins decreased sharply from 8 hours after treatment, and the late S and $G_2$ peaks of gag protein synthesis were disappeared. This shows the stability of viral RNA for about 6 hours in the absence of continuing viral RNA synthesis.

• 대한한방내과학회지
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• 제34권1호
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• pp.1-13
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• 2013

Objectives : The purpose of this study was to investigate the effects of Jowiseungcheung-tang (JWSCT) extract on the lipid metabolism, anti-oxidation and inflammatory reflex. Methods : Male Sprague-Dawley rats were fed a high fat diet for 8 weeks and were randomly divided into 4 groups (10 mice in each group): control group, 100 mg/kg JWSCT group, 200 mg/kg JWSCT group, 300 mg/kg JWSCT group. The control group was administered 100 mg/kg of water, but the other three groups were administered 100, 200, 300 mg/kg JWSCT extract for 4 weeks. After 4 weeks, we measured lipid level, thiobarbituric acid reactive substance (TBARS), glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), catalase (CAT), aspartate aminotransferase (AST), alanine aminotransferase (ALT) and cytokines in plasma and liver. The gene expression level and the ratio of apo-B and apo-E were then investigated by way of reverse transcription -polymerase chain reaction (RT-PCR). Results : In the JWSCT group, compared with the control, free fatty acid, triglyceride, total cholesterol, LDL-cholesterol, TBARS, IL-$1{\beta}$, IL-6 and TNF-${\alpha}$ decreased significantly in plasma and liver. However HDL-cholesterol, IL-10, GSH-Px, SOD and CAT increased. In the JWSCT group, compared with the control, the gene expression level and the ratio of apo-A and apo-E decreased significantly in the RT-PCR analysis. Conclusions : The extract of JWSCT has anti-obesity, anti-inflammatory and anti-oxidant effects.

• 미생물학회지
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• 제45권3호
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• pp.233-238
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• 2009

Corynebacterium ammoniagenes의 purF 유전자의 발현을 purF의 프로모터 추정 부위에 cat 유전자를 융합시킨 transcriptional fusion 플라스미드를 제작하여 분석하였다. 유전자 purF는 adenine과 guanine에 의해 20~30%의 전사 저해효과를 나타내지만, hypoxanthine에는 저해를 받지 않는 것으로 나타났다. 또한 purF의 발현은 대수기중반에 최대에 달한 후 정체기 후반부까지 일정한 것으로 나타났다. 동시에, C. glutamicum에서 사용되는 강력한 프로모터인 $P_{180}$이 Escherichia coli의 $P_{tac}$보다 C. ammoniagenes에서 모든 성장 단계에서 40~50%의 향상된 프로모터 활성을 나타내었고 대수기 후반부에 최고 활성에 달해, C. ammoniagenes의 연구에도 활용 가능함을 확인하였다. DNA-affinity purification에 의해 C. ammoniagenes의 purF 프로모터에 결합하는 단백질로서 C. glutamicum의 Crp-family transcriptional regulator (NCgl0120)와 상동성이 높은 단백질을 검출하였다. 이 단백질은 크기가 40.1 kDa으로서 PAGE에서 관찰된 단백질 크기와 일치하였다. 이에 상응하는 C. ammoniagenes의 단백질은 400개의 아미노산으로 구성되어 있고, 42 kDa의 단백질을 만들며, pI는 4.9일 것으로 추정되었다. 이는 기존에 알려져 있는 E. coli 및 Bacillus subtilis의 PurR과 각각 14.1%, 15.8%의 아미노산 상동성을 보여, PurR과는 다른 종류의 단백질일 것으로 여겨진다.