• Biotechnology and Bioprocess Engineering:BBE
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• v.1 no.1
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• pp.9-12
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• 1996

In order to produce the single chain precursor of a novel human insulin analogue, (B30-Homoserine) insulin, the fermentative behaviors of Escherichia coli JM103 were studied, which harbors pKBA plasmid carrying a hybrid gene in which the gene for a single chain precursor was fused with lacZ gene under tac promoter. The maximal induction of gene expression was achieved when more than 0.05 mM of isopropyl-$\beta$-D-thiogalactopyranoside(IPTG) was supplemented to fermentation medium after 4 h cultivation of E. coli, and followed by longer than 2-h fermentation. The hybrid protein of the single chain insulin precursor was isolated from cytoplasmic inclusion bodies by dissolving in 8M urea solution, and purified through DEAE-Sephacel and Sephadex G-200 column chromatographies with a recovery of 35%. The finally purified hybrid protein showed a single band on sodium dodecyl sulfate-polyacrylamide gel.

• Asian-Australasian Journal of Animal Sciences
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• v.22 no.2
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• pp.168-173
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• 2009

Human follicle-stimulating hormone (hFSH) is a pituitary glycoprotein that regulates follicular development and ovulation. Clinically, hFSH has been used to induce follicular growth in infertile women. The hormone is composed of heterodimers, including a common ${\alpha}$ subunit among the gonadotropin family and a hormone-specific ${\beta}$ subunit. Since assembly of the heterodimer is a rate-limiting step in the production of functional hFSH, transgenic clone cows carrying a single-chain hFSH transgene may efficiently produce functional hormone. Genes encoding the ${\alpha}$ and ${\beta}$ subunits of hFSH were linked using the C-terminal peptide sequence from the ${\beta}$ subunit of human chorionic gonadotropin. Bovine fetal fibroblasts were transfected with the gene construct, including the goat ${\beta}$-casein promoter and a single-chain hFSH coding sequence. Transfected fibroblasts were transferred into enucleated oocytes, and individual nuclear transfer (NT) embryos developed to the blastocyst stage were analyzed for the transgene by polymerase chain reaction. Seventy eight blastocysts (30.8%) were developed from 259 reconstructed embryos. Among these blastocysts, the hFSH gene was detected in 70.8% (34/48) of the embryos. Subsequent transfer of hFSH-transgenic clone embryos to 31 recipients results in 11 (35.5%) early pregnancies. However, all fetuses were lost before reaching day 180 of gestation. The results from this study demonstrated that bovine NT embryos carrying single-chain hFSH could be produced, and further extensive studies in which NT embryos are transferred to more recipients may give rise to single chain hFSH-transgenic cows for biomedical applications.

• Biotechnology and Bioprocess Engineering:BBE
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• v.6 no.2
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• pp.144-149
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• 2001

For the production and purification of a single chain human insulin precursor, four types of fusion peptides $\beta$-galactosidase (LacZ), maltose binding protein (MBP), glutathione-S-transferase (GST), and (His)(sub)6-tagged sequence (HTS) were investigated. Recombinant E. coli harboring hybrid genes was cultivated at 37$\^{C}$ for 1h, and gene induction occurred when 0.2mM of isopropyl-D-thiogalactoside (IPTG) was added to the culture broth, except for E. coli BL21 (DE3) pLysS harboring a pET-BA cultivation with 1.0mM IPTG, followed by a longer than 4h batch fermentation respectively. DEAE-Sphacel and Sephadex G-200 gel filtration chromatography, amylose affinity chromatography, glutathione-sepharose 4B affinity chromatography, and a nickel chelating affinity chromatography system as a kind of immobilized metal ion affinity chromatography (IMAC) were all employed for the purification of a single chain human insulin precursor. The recovery yields of the HTS-fused, GST-fused, MBP-fused, and LacZ-fused single chain human insulin precursors resulted in 47%, 20%, 20%, and 18% as the total protein amounts respectively. These results show that a higher recovery yield of the finally purified recombinant peptides was achieved when affinity column chromatography was employed and when the fused peptide had a smaller molecular weight. In addition the pET expression system gave the highest productivity of a fused insulin precursor due to a two-step regulation of the gene expression, and the HTS-fused system provided the highest recovery of a fused insulin precursor based on a simple and specific separation using the IMAC technique.

• Clinical and Experimental Reproductive Medicine
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• v.21 no.3
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• pp.281-284
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• 1994

Sex determination in genomic DNA from human blood leucocytes was performed by amplification of human Y chromosome-specific DNA sequences using PCR technique. A clear DNA fragment(154 nucleotides long) was appeared only in the male genomic DNA, but no specific band was observed in the case of female genomic DNA and negative control. To know the sensitivity of this method, the amplification reaction was performed in genomic DNA diluted to 2pg equivalent to the amonut present in the single human cell, and clear band also observed. The PCR amplification was so succesfully performed in the single leucocyte separated from human blood using micromanipulator that this techniqe is assumed to be applied to single blstomere before embryo transfer.

• BMB Reports
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• v.30 no.3
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• pp.177-181
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• 1997

We constructed a single-chain immunoglobulin in which the carboxyl end of the heavy chain variable domain is covalently joined to the amino terminus of the light chain variable domain via peptide linker and the carboxyl end of the light chain variable domain is linked to human ${\gamma}1$ Fc region through the hinge region. The molecule was expressed in Chinese hamster ovary cells, assembled into a dimeric molecule and secreted into the culture medium. The dimeric molecule (2E11) was purified from the culture supernatant by affinity chromatography on Protein G-Sepharose column. The size of the unreduced or reduced protein was the expected molecular weight of approximately 120 or 60 kDa, respectively, as assessed by SDS-polyacrylamide gel electrophoresis. The antigen-binding affinity of 2E11 was almost the same as that of a native antibody counterpart (CS131A), suggesting that the single-chain immunoglobulin may function like a native antibody.

• Archives of Pharmacal Research
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• v.16 no.4
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• pp.271-275
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• 1993

In order to prepare a novel human insulin analogue suhbstituted with homoserine at B$^{30}$ / position, (B$^{30}$ /-homoserine) human insulin, a synthetic gene was designed by linking directly a gene for B chain with that for A chain. This gene was constructed by enzymatic joining of 10 different synthetic oligonucleotides, and then inserted at the polylinker region of pUC19 plasmid. To achieve a high level of gene expression, the gene fusion technique region of pUC19 plasmid. To achieve a high level of gene expression, the gene fusion technique was employed using amino terminal regions of lacZ gene up to Clal or hpal, and either of them has been located under tac promoter. The chemical induction of these fused genes by isopropyl-.betha.-D-thiogalactopyranoside (IPTG) gave a satisfactory level of expression in Escherichia coli harboring the ocnstructed plasmids. It was observed that the fused gene product as a single chain insulin precusor was produced more than 30% of total cell protein of E. coli as a form of inclusion body.

• Korean Journal of Microbiology
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• v.51 no.2
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• pp.115-125
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• 2015

A monoclonal antibody AP64 IgM binds to human acute nonlymphocytic leukemia (ANLL) cell line HL60 and also cross-reacts with the homologous antigen in a rat ANLL cell. This antibody mediated by complement, has leukemia a suppression effect. In this study, we generated a recombinant single-chain variable domain fragment (ScFv) which were derived from $V_H$ and $V_L$ cDNA of AP64 IgM-secreting hybridoma by RT-PCR. The two variable regions were joined with a single 15 amino acid linker $(G_4S)_3$. This recombinant ScFv was expressed as a single polypeptide chain from Escherichia coli BMH 71-18. The recombinant ScFv was purified by applying the periplasmic extract to $Ni^+$-NTA-agarose affinity column and detected with westernblot. The purified recombinant ScFv recognized a surface antigen (about 30 kDa) of HL60 cell line which is the same antigen detected by parental AP64 IgM. But the affinity of ScFv for a surface antigen of HL60 was lower than that of the parental AP64 IgM, which needs to be further improved. Overall, the recombinant ScFv specific to HL60 might be a useful bioreagent for either diagnostic or therapeutic purposes.

• Journal of the Korean Chemical Society
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• v.49 no.6
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• pp.537-545
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• 2005

• IMMUNE NETWORK
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• v.12 no.1
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• pp.33-39
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• 2012

Background: Therapeutic approaches using monoclonal antibodies (mAbs) against complement regulatory proteins (CRPs:i.e.,CD46,CD55 and CD59) have been reported for adjuvant cancer therapy. In this study, we generated a recombinant 1E8 single-chain anti-CD59 antibody (scFv-Fc) and tested anti-cancer effect.by using complement dependent cytotoxicity (CDC). Methods: We isolated mRNA from 1E8 hybridoma cells and amplified the variable regions of the heavy chain (VH) and light chain (VL) genes using reversetranscriptase polymerase chain reaction (RT-PCR). Using a linker, the amplified sequences for the heavy and light chains were each connected to the sequence for a single polypeptide chain that was designed to be expressed. The VL and VH fragments were cloned into the pOptiVEC-TOPO vector that contained the human CH2-CH3 fragment. Then, 293T cells were transfected with the 1E8 single-chain Fv-Fc (scFv-Fc) constructs. CD59 expression was evaluated in the prostate cancer cell lines using flow cytometry. The enhancement of CDC effect by mouse 1E8 and 1E8 scFv-Fc were evaluated using a cytotoxicity assay. Results: The scFv-Fc constructs were expressed by the transfected 293T cells and secreted into the culture medium. The immunoreactivity of the secreted scFv-Fc construct was similar to that of the mouse 1E8 for CCRF-CEM cells. The molecular masses of 1E8 scFv-Fc were about 120 kDa and 55 kDa under reducing and non-reducing conditions, respectively. The DNA sequence of 1E8 scFv-Fc was obtained and presented. CD59 was highly expressed by the prostate cancer cell line. The recombinant 1E8 scFv-Fc mAb revealed significantly enhanced CDC effect similar with mouse 1E8 for prostate cancer cells. Conclusion: A 1E8 scFv-Fc construct for adjuvant cancer therapy was developed.

• Clinical and Experimental Pediatrics
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• v.53 no.2
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• pp.129-135
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• 2010

Human rhinoviruses (HRVs) is a nonenveloped, single stranded RNA virus belonging to the family Picornavirudae. Transmission by direct contact such as hand-to-hand, hand-to-nose, and hand-to-eye has been readily demonstrated in experimental settings. HRV are the most frequent causes of common cold infection, however, they are also known to replicate in the lower respiratory tract and associated with more severe respiratory illnesses such as asthma. New technique such as reverse transcriptase polymerase chain reaction and molecular typing in HRV has been developed and our understanding of the importance of these respiratory viruses. HRVs consisted of 101 serotypes that are classified into groups A and B according to sequence variations. And there is a newly identified set of HRVs, called Group C, and it is currently under investigation. In recent study using PCR techniques, HRVs accounted for approximate 50-80% of common colds and 85 % of childhood asthma exacerbations and in more than half of adult exacerbations. However, the mechanisms of HRV- induced asthma exacerbations are poorly understood. This review discusses the association between HRVs and childhood asthma.