- Production and Characterization of Monoclonal Antibodies to Human Immunodeficiency Virus Type 1 gp120 Envelope Glycoprotein
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Choi, Eui Yul , Ryu, Ji Yoon , Lee, Yoon , Ha, Sung Gil , Chung, So Young , Park, Sang Yeol , Nham, Sang Uk , Lee, Young Ik , Park, Jin Seu
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J. Microbiol. 1998;36(1):59-65.
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 Abstract
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Monoclonal antibodies to human immunodeficiency virus type 1 envelope glycoprotein gp 120(HIV-1 gp120) were produced and characterized. For immunogen recombinant gp120 polypeptide expressed in bacteria was prepared and injected into mice. From two fusion experiments, twenty hybridomas secreting monoclonal antibodies against the recombinant gp120 were initially screened by immunodot blot analysis. Among the antibodies, 15 of them showed strong reactivities with the recombinant protein expressed in bacteria in Western blot and thus it was tested if these could react with the recombinant protein expressed in insect cells. All of the 15 antibodies immunostained the protein band with varing degrees of reactivities. Next, we tested whether the antibodies recognize authentic gp120 protein expressed in mammalian cells. COS-1 cells were tranfected with the cDNA encoding gp120 protein, and the transiently ecpressed protein were analyzed with the mAbs by Western blot analysis and immunofluorescence microscopy. Six of the monoclonal antibodies reacted with the protein band of authentic gp120 expressed in mammalian cells in the Western blot, and five stained the cell periphery of the transfected COS-1 cells in immunofluorescence. The mAbs described in this study should prove to be useful tools for the biochemical, immunological and structural analysis of HIV-1 gp120 envelope glycoprotein.
- Expression of immunologically active porcine recombinant TGF-β1 precursor protein in baculovirus system
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Lim, Hyun , Kim, Pyeung Hyeun , Chun, Gie Taek , Choi, Eui Yul , Yie, Se Won
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J. Microbiol. 1997;35(4):341-346.
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Abstract
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In order to express recombinant porcine TGF-β1 protein in a baculovirus expression system the entire TGF-β1 gene containing extra amino acids at the N terminus was cloned into pFBa and pFBb of the Bac-To-Bac^TM baculovirus expression system. One of the clones contained 106 extra amino acids and was designated pFBa-106 TGF-β1, and the other had 28 extra amino acids and was designated pFBb-28 TGF-β1. The orientation of the gene was identified with restriction enzyme mapping and PCR with internal TGF-β1 primers. Sf-9 cells were infected at a m.o.i. of 10 by the recombinant viruses generated from the two expected sizes of 55 kD and 46.4kD. these precursor forms of TGF-β1 with a polyclonal antibody against human TGF-β1. No mature form of TGF-β1 protein was detected on SDS gels and an immunoblot indicated that TGF-β1 precursor is not properlu processed in insect cells.
- Identification and characterization of pH-regulated genes in saccharomyces cerevisiae
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Hong, Sung Ki , Choi, Eui Yul
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J. Microbiol. 1996;34(4):327-333.
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Yeast, like many other microbes, encounters large variations in ambient pH in their natural environments. Microorganisms capable of growing over a wide pH range require a versatile, efficient pH homeostatic mechanism protecting intracellular processes against extremes of pH. In several organisms, fusions to the bacterial lacZ gene have been extremely useful for the identification of genes expressed at different time during the life cycle or under different growth conditions. In this study, using the lacZ gene screening system, we surveyed a large number of yeast strains with lacZ insertion to identify genes regulated by pH. A yeast genomic library was constructed and inserted with lacZ by a shuttle mutagenesis procedure. The yeast transformants were individually picked up with a toothpick, replica-plated, and grown in alkaline pH medium. Among the 35,000 colonies screened, 10 candidate strains were identified initially by the β-gal assay. We finally confirmed two yeast strains carrying the genes whose expression are strictly dependent on pH of growth medium. One of the fusions showing a 10-fodl induction in expression level in response to alkali pH was selected and further characterized. The pH-regulated gene was cloned by inverse PCR and a partial sequence of the gene was determined. Identification and characterization of the gene is currently under investigation.
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