Association of Extracellular Cleavage of E-Cadherin Mediated by MMP-7 with HGF-Induced in vitro Invasion in Human Stomach Cancer Cells

Lee, K.H.,Choi, E.Y.,Hyun, M.S.,Jang, B.I.,Kim, T.N.,Kim, S.W.,Song, S.K.,Kim, J.H.,Kim, J.-R. S. Karger AG 2007 European surgical research Vol.39 No.4

<P><I>Background:</I> Proteolytic shedding of the ectodomain of a variety of transmembrane proteins, including cell-to-cell adhesion molecules, has been observed in solid cancers. We have investigated whether extracellular cleavage of E-cadherin mediated by matrix metalloproteinase-7 (MMP-7) is involved in hepatocyte growth factor (HGF) induced in vitro invasion in stomach cancer cells. <I>Methods:</I> The effects of HGF on the expression of E-cadherin/β-catenin and MMP-7 at both the protein and mRNA levels were assessed in stomach cancer cells, NUGC-3 and MKN-28, and in cells in which the expression of MMP-7 was downregulated by transfection with a MMP-7 short hairpin RNA plasmid. <I>Results:</I> Treatment with HGF increased the extracellular cleavage of E-cadherin and the release of MMP-7 and reduced the level of E-cadherin in a dose- and time-dependent manner. HGF treatment repressed the phosphorylation of β-catenin in a Triton-soluble fraction, but enhanced this phosphorylation in a Triton-insoluble fraction. The association of E-cadherin with β-catenin was decreased by HGF treatment in the Triton-soluble fraction. In addition, treatment of MMP-7 short hairpin RNA transfected NUGC-3 cells with HGF resulted in no extracellular cleavage of E-cadherin and also decreased the in vitro cell invasion. <I>Conclusions:</I> These results suggest that incubation with HGF mediated the release of MMP-7, resulting in extracellular cleavage of E-cadherin from stomach cancer cells. This might be a key mechanism in HGF-induced in vitro invasion and metastasis.</P><P>Copyright © 2007 S. Karger AG, Basel</P>

A novel chimeric promoter that is highly responsive to hypoxia and metals

Lee, J-Y,Lee, Y-S,Kim, J-M,Kim, K L,Lee, J-S,Jang, H-S,Shin, I-S,Suh, W,Jeon, E-S,Byun, J,Kim, D-K Nature Publishing Group 2006 Gene Therapy Vol.13 No.10

To develop a potent hypoxia-inducible promoter, we evaluated the usefulness of chimeric combinations of the (Egr-1)-binding site (EBS) from the Egr-1 gene, the metal-response element (MRE) from the metallothionein gene, and the hypoxia-response element (HRE) from the phosphoglycerate kinase 1 gene. In transient transfection assays, combining three copies of HRE (3 × HRE) with either EBS or MRE significantly increased hypoxia responsiveness. When a three-enhancer combination was tested, the EBS–MRE-3 × HRE (E–M–H) gave a hypoxia induction ratio of 69. The expression induced from E–M–H-pGL3 was 2.4-fold higher than that induced from H-pGL3 and even surpassed the expression from a human cytomegalovirus promoter-driven vector. The high inducibility of E–M–H was confirmed by validation studies in different cells and by expressing other cDNAs. Gel shift assays together with functional overexpression studies suggested that increased levels of hypoxia-inducible factor 1α, metal transcription factor-1 and Egr-1 may be associated with the high inducibility of the E–M–H chimeric promoter. E–M–H was also induced by hypoxia mimetics such as Co<SUP>2+</SUP> and deferoxamine (DFX) and by hydrogen peroxide. Gene expression from the E–M–H was reversible as shown by the reduced expression of the transgene upon removal of inducers such as hypoxia and DFX. In vivo evaluation of the E–M–H in ischemic muscle revealed that erythropoietin secretion and luciferase and LacZ expression were significantly higher in the E–M–H group than in a control or H group. With its high induction capacity and versatile means of modulation, this novel chimeric promoter should find wide application in the treatment of ischemic diseases and cancer.Gene Therapy (2006) 13, 857–868. doi:10.1038/sj.gt.3302728; published online 9 February 2006

NMR study of hydrogen exchange during the B-Z transition of a DNA duplex induced by the Zα domains of yatapoxvirus E3L

Lee, E.H.,Seo, Y.J.,Ahn, H.C.,Kang, Y.M.,Kim, H.E.,Lee, Y.M.,Choi, B.S.,Lee, J.H. North-Holland Pub ; Elsevier Science Ltd 2010 FEBS letters Vol.584 No.21

The Yaba-like disease viruses (YLDV) are members of the Yatapoxvirus family and have double-stranded DNA genomes. The E3L protein, which is essential for pathogenesis in the vaccinia virus, consists of two domains: an N-terminal Z-DNA binding domain and a C-terminal RNA binding domain. The crystal structure of the E3L orthologue of YLDV (yabZα<SUB>E3L</SUB>) bound to Z-DNA revealed that the overall structure of yabZα<SUB>E3L</SUB> and its interaction with Z-DNA are very similar to those of hZα<SUB>ADAR1</SUB>. Here we have performed NMR hydrogen exchange experiments on the complexes between yabZα<SUB>E3L</SUB> and d(CGCGCG)<SUB>2</SUB> with a variety of protein-to-DNA molar ratios. This study revealed that yabZα<SUB>E3L</SUB> could efficiently change the B-form helix of the d(CGCGCG)<SUB>2</SUB> to left-handed Z-DNA via the active-mono B-Z transition pathway like hZα<SUB>ADAR1</SUB>1.

Association and functional relevance of E237G, a polymorphism of the high-affinity immunoglobulin E-receptor β chain gene, to airway hyper-responsiveness

Kim, Y.-K.,Park, H.-W.,Yang, J.-S.,Oh, S.-Y.,Chang, Y.-S.,Shin, E.-S.,Lee, J.-E.,Kim, S.,Gho, Y. S.,Cho, S.-H.,Min, K.-U.,Kim, Y.-Y. Blackwell Scientific Publications 2007 Clinical and experimental allergy Vol.37 No.4

<P>Summary</P><P>Background</P><P>The hyper-sensitivity reaction of IgE, with its high-affinity receptors (FcϵRI), is central to the phenomenon of atopic diseases.</P><P>Objective</P><P>To evaluate the genetic effects of non-synonymous single-nucleotide polymorphisms (SNPs) of FcϵRI on intermediate phenotypes of asthma, i.e. atopy and airway hyper-responsiveness (AHR), in the Korean general population.</P><P>Subjects and methods</P><P>Atopy and AHR were evaluated in a cohort of 2055 subjects, aged 10–18 years, using skin prick tests (SPTs) for common aeroallergens and total serum IgE and methacholine bronchial provocation tests. All FcϵRI-α, FcϵRI-β, and FcϵRI-γ gene exons of 24 healthy subjects were sequenced to locate informative non-synonymous SNPs (minor allele frequency >2%). Informative SNPs were then scored, using the high-throughput single base extension method. Relative risk (RR) was determined by multiple logistic regression analysis, after adjusting for confounding factors. The functional relevance of non-synonymous SNPs was analysed using the sorting intolerant from tolerant (SIFT) program.</P><P>Results</P><P>The SNP search found only one informative non-synonymous SNP in FcϵRI-β: E237G (minor allele frequency=0.21). The positive rate of AHR was lower among subjects with the 237<SUP>*</SUP>E allele than among those with 237<SUP>*</SUP>G [RR (95% confidence interval)=0.41 (0.19–0.89); <I>P</I>=0.01]. However, the E237G substitution was not associated with either a positive SPT response or total serum IgE levels. Sequence evolution analysis predicted that the E237G variation is an intolerant amino acid substitution, with functional importance.</P><P>Conclusion</P><P>In the Korean general population, AHR is significantly associated with the E237G polymorphism of FcϵRI-β, which results in an intolerant amino acid substitution.</P>

화력발전소의 대기오염물질 배출계수 산정 연구

김대곤,엄윤성,홍지형,이석조,석광설,이대균,이은정,방선애 한국대기환경학회 2004 한국대기환경학회지 Vol.20 No.3

The main purpose of this study was to characterize the air pollutants emission factors in electric power plant (EPP) using fossil fuels. The electric power plant is a major air pollution source, thus knowing the emission characteristics of electric power plant is very important to develop a control strategy. The major air pollutants of concern from EPP stacks are particulate matter (PM), sulfur oxides (SOx), nitrogen oxides (NOx), carbon monoxide (CO) and heavy metals. Throughout the study. the following results arc estimated: - PM : 8.671E-05∼8.724E+01 PM emission (kg) per fuel burned (ton) - SOx: 4.749E-04∼7.877E+01 SOx emission (kg) per fuel burned (ton) - NOx : 1.578E-02∼9.857E+00 NOx emission (kg) per fuel burned (ton) - CO : 3.800E-04∼1.291E+00 CO emission (kg) per fuel burned (ton) - Hg : 1.220E+01∼3.108E+02 Hg emission (mg) per fuel burned (ton) From the statistical analysis by Wilcoxon signed ranks test between the emission factors of ours and U.S. EPA's. we can yielded that: p > 0.05.

Interpretation of cryogenic-temperature Charpy fracture initiation and propagation energies by microstructural evolution occurring during dynamic compressive test of austenitic Fe-(0.4,1.0)C-18Mn steels

Kim, H.,Park, J.,Jung, J.E.,Sohn, S.S.,Lee, S. Elsevier Sequoia 2015 Materials science & engineering. properties, micro Vol.641 No.-

In the present study, Charpy impact energy (E<SUB>T</SUB>) composed of fracture initiation energy (E<SUB>I</SUB>) and propagation energy (E<SUB>P</SUB>) of austenitic Fe-(0.4,1.0)C-18Mn steels was evaluated in the temperature range from room to cryogenic temperatures by an instrumented Charpy impact tester, and was interpreted by microstructural evolution of dynamically compressed specimens. In the 1.0C-18Mn steel, the E<SUB>I</SUB> and E<SUB>P</SUB> decreased slightly with decreasing temperature, but the E<SUB>P</SUB>/E<SUB>T</SUB> ratio was kept to be about 0.5. In the 0.4C-18Mn steel, the E<SUB>I</SUB> remained almost constant or slightly decreased with decreasing temperature, while the E<SUB>P</SUB>/E<SUB>T</SUB> ratio steadily decreased, thereby leading to the lower (about 30%) cryogenic-temperature E<SUB>T</SUB> than that of the 1.0C-18Mn steel. Under the dynamic compressive loading, a considerable number of ε-martensites were formed in the 0.4C-18Mn steel, whereas they were not found in the 1.0C-18Mn steel, and their volume fractions increased steadily with decreasing temperature. This γ→ε-martensite transformation was attributed to the decrease in stacking fault energy, and resulted in the very low E<SUB>P</SUB> and resultant E<SUB>T</SUB>.

E-Pulse와 신경망을 이용한 표적 구분에 관한 연구

이승재(Seung-Jae Lee),최인식(In-Sik Choi),E. J. Rothwell 한국정보기술학회 2012 Proceedings of KIIT Conference Vol.2012 No.5

레이다 표적 인식을 위한 특성벡터로는 초기 시간 영역 응답의 산란점과 후기 시간 영역 응답인 고유 주파수가 있다. 본 논문에서는 레이다 표적 구분을 위해 고유 주파수를 사용하는 E-Pulse 기법을 이용하여 세 가지 종류의 선형 표적에 대해 표적 구분 실험을 수행하였다. 그리고, E-Pulse 기법을 사용하여 추출된 고유 주파수를 multi-layerd perceptron(MLP) 신경망 구분기의 입력으로 사용하여 표적 구분 성능 실험을 수행하였으며, SNR의 따른 표적 구분 확률을 확인하였다. Feature vectors used for radar target recognition are scattering centers of early time response and natural frequencies of late time response. In this paper, we performed radar target classification for three types of wire targets. E-Pulse method is used for the natural frequency extraction. The extracted natural frequency is used as input for the multi-layerd perceptron(MLP) neural network classifier. In the results, we show the target classification probability with respect to SNR.

EZH2 Generates a Methyl Degron that Is Recognized by the DCAF1/DDB1/CUL4 E3 Ubiquitin Ligase Complex

Lee, J.,Lee, Jason S.,Kim, H.,Kim, K.,Park, H.,Kim, J.Y.,Lee, S.,Kim, I.,Kim, J.,Lee, M.,Chung, C.,Seo, S.B.,Yoon, J.B.,Ko, E.,Noh, D.Y.,Kim, K.,Kim, K.,Baek, S. Cell Press 2012 Molecular cell Vol.48 No.4

Ubiquitination plays a major role in protein degradation. Although phosphorylation-dependent ubiquitination is well known for the regulation of protein stability, methylation-dependent ubiquitination machinery has not been characterized. Here, we provide evidence that methylation-dependent ubiquitination is carried out by damage-specific DNA binding protein 1 (DDB1)/cullin4 (CUL4) E3 ubiquitin ligase complex and a DDB1-CUL4-associated factor 1 (DCAF1) adaptor, which recognizes monomethylated substrates. Molecular modeling and binding affinity studies reveal that the putative chromo domain of DCAF1 directly recognizes monomethylated substrates, whereas critical binding pocket mutations of the DCAF1 chromo domain ablated the binding from the monomethylated substrates. Further, we discovered that enhancer of zeste homolog 2 (EZH2) methyltransferase has distinct substrate specificities for histone H3K27 and nonhistones exemplified by an orphan nuclear receptor, RORα. We propose that EZH2-DCAF1/DDB1/CUL4 represents a previously unrecognized methylation-dependent ubiquitination machinery specifically recognizing ''methyl degron''; through this, nonhistone protein stability can be dynamically regulated in a methylation-dependent manner.

Efficient proteolytic cleavage by insertion of oligopeptide linkers and its application to production of recombinant human interleukin-6 in Escherichia coli

Lee, E.G.,Baek, J.E.,Lee, S.H.,Kim, T.W.,Choi, J.H.,Rho, M.C.,Ahn, J.O.,Lee, H.W.,Jung, J.K. IPC Science and Technology Press ; Elsevier Scienc 2009 Enzyme and microbial technology Vol.44 No.5

Efficient expression and purification of bioactive recombinant human interleukin-6 (hIL6) was successfully achieved in Escherichia coli (E. coli) by fusion of the maltose-binding protein (MBP) with hIL6 and the insertion of oligopeptide linkers. MBP/hIL6 was over-expressed in the soluble form at a concentration of approximately 2.5g/L. For hIL6 recovery, enterokinase, factor Xa, and thrombin were employed to cleavage MBP from the fusion constructs. However, undesired and non-specific cleavage fragments as well as rhIL6 were obtained following the cleavage. The introduction of oligopeptide linkers at the C-terminal end of the fusion construct could improve the efficiency and the rate of the enzymatic cleavage reaction, and the rhIL6 purification was achieved by using MBP affinity chromatography, factor Xa cleavage, and reverse-phase chromatography, resulting in an overall yield as high as 33% (equivalent to 0.27ghIL6/L) at purity over 98%. The biological activity of the purified recombinant hIL6 was demonstrated by confirming the presence of the signal transducer and activator of transcription 3 (STAT3) signaling pathway. This study suggests that the optimized peptide linker specifically designed for both fusion partner and target molecule has a great potential for efficient recombinant protein production.

Development of Escherichia coli MG1655 strains to produce long chain fatty acids by engineering fatty acid synthesis (FAS) metabolism

Jeon, E.,Lee, S.,Won, J.I.,Han, S.O.,Kim, J.,Lee, J. IPC Science and Technology Press ; Elsevier Scienc 2011 Enzyme and microbial technology Vol.49 No.1

The goal of this research was to develop recombinant Escherichia coli to improve fatty acid synthesis (FAS). Genes encoding acetyl-CoA carboxylase (accA, accB, accC), malonyl-CoA-[acyl-carrier-protein] transacylase (fabD), and acyl-acyl carrier protein thioesterase (EC 3.1.2.14 gene), which are all enzymes that catalyze key steps in the synthesis of fatty acids, were cloned and over-expressed in E. coli MG1655. The acetyl-CoA carboxylase (ACC) enzyme catalyzes the addition of CO<SUB>2</SUB> to acetyl-CoA to generate malonyl-CoA. The enzyme encoded by the fabD gene converts malonyl-CoA to malonyl-[acp], and the EC 3.1.2.14 gene converts fatty acyl-ACP chains to long chain fatty acids. All the genes except for the EC 3.1.2.14 gene were homologous to E. coli genes and were used to improve the enzymatic activities to over-express components of the FAS pathway through metabolic engineering. All recombinant E. coli MG1655 strains containing various gene combinations were developed using the pTrc99A expression vector. To observe changes in metabolism, the in vitro metabolites and fatty acids produced by the recombinants were analyzed. The fatty acids (C16) from recombinant strains were produced 1.23-2.41 times higher than that from the wild type.