• Journal of Microbiology and Biotechnology
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• v.16 no.9
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• pp.1362-1368
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• 2006

A new constitutive episomal expression vector, pGAPZ-E, was constructed and used for initial screening of eukaryotic target gene expression in Pichia pastoris. Two reporter genes such as beta-galactosidase gene and GFPuv gene were overexpressed in P. pastoris. The expression level of the episomal pGAPZ-E strain was higher than that of the integrated form when the beta-galactosidase gene was used as the reporter gene in P. pastoris X33. The avoiding of both the integration procedure and an induction step simplified the overall screening process for eukaryotic target gene expression in P. pastoris. Nine human protein targets from the Core 50, family of Northeast Structural Genomics Consortium (http://www.nesg.org), which were intractable when expressed in E. coli, were subjected to rapid screening for soluble expression in P. pastoris. HR547, HR919, and HR1697 human proteins, which had previously been found to express poorly or to be insoluble in E. coli, expressed in soluble form in P. pastoris. Therefore, the new episomal GAP promoter vector provides a convenient and alternative system for high-throughput screening of eukaryotic protein expression in P. pastoris.

• Microbiology and Biotechnology Letters
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• v.51 no.1
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• pp.37-42
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• 2023

Neutral and non-essential amino acid, glutamine (Gln), plays an essential role in supplying nitrogen to all the amino acids and nucleotides in the mammalian body. Gln is also the most important carbon source that provides intermediates for gluconeogenesis and fatty acid synthesis and supplements the tricarboxylic acid cycle in fast-growing cancer cells. Among the known 14 Gln transporter genes, soluted carrier family 1 member 5 (SLC1A5) has been reported to be closely associated with cancer cell growth. Three variants (v1, v2, and v3) have been derived from SLC1A5. Here, we established a heterologous gene expression system for the active form of human SLC1A5 variant-2 (hSLC1A5v2) in Escherichia coli. v2 is the smallest variant that has not yet been studied. Four expression systems were investigated: pBAD, pCold, pET, and pQE. We also addressed the problem of codon usage bias. Although pCold and pET overexpressed hSLC1A5v2 in E. coli, they were functionally inactive. hSLC1A5v2 using the pBAD system was able to catalyze the successful transport of Gln, even if it was not highly expressed. Initial activity of hSLC1A5v2 for [¹⁴C] Gln uptake in E. coli reached up to 6.73 μmole·min^-1·gDW^-1 when the cell was induced with 80 mM L-arabinose. In this study, we demonstrated a heterologous expression system for the human membrane protein, SLC1A5, in E. coli. Our results can be used for the functional comparison of SLC1A5 variants (v1, v2, and v3) in future studies, to facilitae the developement of SLC1A5 inhibitors as effective anticancer drugs.

• Food Science and Biotechnology
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• v.17 no.5
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• pp.1115-1118
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• 2008

${\alpha}$-Galactosidase gene (aga) from Leuconostoc mesenteroides SY1 was expressed in a heterologous host, Lactobacillus brevis 2.14 using an Escherichia coli-Leuconostoc shuttle vector, pSJE. pSJEaga (pSJE carrying aga) was introduced into Lactobacillus brevis 2.14 by electroporation and transformation efficiency was $1.1{\times}10^3$ per ${\mu}g$ DNA. L. brevis transformants (TFs) showed higher ${\alpha}$-galactosidase (${\alpha}$-Gal) activities than cells containing pSJE. Transcription levels of aga in L. brevis 2.14 grown on different carbon sources (1%, w/v) were examined by slot blot analysis. Aga transcript levels and ${\alpha}$-Gal activities were higher in cells grown on melibiose, raffinose, and galactose than cells on glucose, sucrose, and fructose. Western blot result showed that L. brevis 2.14 harboring pSJEaga produced much more ${\alpha}$-Gal when grown on melibiose than on glucose.

• Korean Journal of Microbiology
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• v.30 no.2
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• pp.108-112
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• 1992

To investigate the expression and the secretion of heterologous proteins in yeast, we constructed an yeast secretion vector and produced a human secretory protein, .alpha.-1-antitrypsin (.alpha.-1-AT), from yeast cells. The secretion vector pGAT8 was constructed by inserting the signal sequence of yeast acid phosphatase gene (PH05) into the .alpha.1-AT expression vector pGAT6 which contained .alpha.-1-AT cDNA fused to GAL10-CYC1 promotor. The .alpha.-1-AT was produced efficiently in the yeast cells transformed with plasmid pGAT8, which was onfirmed both by the .alpha.-1-AT activity assay and by the immunoblot method using .alpha.-1-AT antibody. We also showed the secretion of .alpha.-1-AT into the culture media and into the periplasmic space by immunoblot.

• Journal of Microbiology and Biotechnology
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• v.18 no.5
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• pp.866-873
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• 2008

2-Deoxystreptamine is a core aglycon that is vital to backbone formation in various aminoglycosides. This core structure can be modified to develop hybrid types of aminoglycoside antibiotics. We obtained three genes responsible for 2-deoxystreptamine production, neo7, neo6, and neo5, which encode 2-deoxy-scyllo-inosose synthase, L-glutamine: 2-deoxy-scyllo-inosose aminotransferase, and dehydrogenase, respectively, from the neomycin gene cluster. These genes were cloned into pIBR25, a Streptomyces expression vector, resulting in pNDOS. The recombinant pNDOS was transformed into a non-aminoglycoside-producing host, Streptomyces venezuelae YJ003, for heterologous expression. Based on comparisons of the retention time on LC-ESI/MS and ESI-MS data with those of the 2-deoxystreptamine standard, a compound produced by S. venezuelae YJ003/pNDOS was found to be 2-deoxystreptamine.

• Journal of Microbiology and Biotechnology
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• v.17 no.1
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• pp.130-137
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• 2007

A disease resistance related gene, MbR7, was identified in the wild apple species, Malus baccata. The MbR7 gene has a single open reading frame (ORF) of 3,288 nucleotides potentially encoding a 1,095-amino acid protein. Its deduced amino acid sequence resembles the N protein of tobacco and the NL27 gene of potato and has several motifs characteristic of a TIR-NBS-LRR R gene subclass. Ectopic expression of MbR7 in Arabidopsis enhanced the resistance against a virulent pathogen, Pseudomonas syringae pv. tomato DC3000. Microarray analysis confirmed the induction of defense-related gene expression in 35S::MbR7 heterologous Arabidopsis plants, indicating that the MbR7 gene likely activates a downstream resistance pathway without interaction with pathogens. Our results suggest that MbR7 can be a potential target gene in developing a new disease-resistant apple variety.

• Journal of Microbiology and Biotechnology
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• v.10 no.1
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• pp.115-118
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• 2000

Recombinant plasmids harboring a heterologous gene coding for the enhanced green fluorescent protein (EGFP) were transfected and expressed in Drosophila melanogaster S2 cells. A stable transformation of polyclonal cell populations expressing EGFP were isolated after 4 weeks of selection with hygromycin B. The recombinant EFGP expressed in transformed S2 cells consisted of a molecular weight of 27 kDa. EGFP expression was also confirmed by fluorometric measurement. The maximum EGFP concentration was about 9.3 mg/I. The present findings demonstrate not only the successful stable expression of EGFP in Drosophuila was about 9.3 mgI. The present findings demonstrate not only the successful stable expression of EGFP in Drosophila S2 cells, but also the use of EGFP as a reporter to analyze gene expression, with its potential of a Drosophila cell expression system for recombinant protein production being an alternative to a baculovirus-insect cell expression system.

• Microbiology and Biotechnology Letters
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• v.22 no.5
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• pp.477-484
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• 1994

Using a methylotrophic yeast Hansenula polymorpha, a heterologous gene expression and secretion system was developed for the production of hEGF(human Epidermal Growth Factor) which has been shown to promote epithelial cell proliferation and to inhibit gastric acid secretion. The hEGF gene was chemically synthesized according to the preferred codon usage in H. polymor- pha and expressed under the control of the strong and inducible methanol oxidase(MOX) promoter. The mating factor $\alpha$ pre-pro leader sequence of Saccharomyces cerevisiae was employed for hEGF to be secreted into the extracellular medium. This expression cassette was stably integrated into the host chromosomal DNA. Mature hEGF was efficiently expressed and secreted into the extracel- lular medium. About 24 mg/l of hEGF was detected in the cuture supernatant of a transformant with pA-EGF3 under the suboptimal culture conditions.

• Mycobiology
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• v.47 no.3
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• pp.301-307
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• 2019

The $11{\alpha}$-hydroxylation of $16{\alpha}$, 17-epoxyprogesterone (EP) catalyzed by Rhizopus nigricans is crucial for the steroid industry. However, lower conversion rate of the biohydroxylation restricts its potential industrial application. The $11{\alpha}$-steroid hydroxylase CYP509C12 from R. oryzae were reported to play a crucial role in the $11{\alpha}$-hydroxylation in recombinant fission yeast. In the present study, the CYP509C12 of R. oryzae (RoCYP) was introduced into R. nigricans using the liposome-mediated mycelial transformation. Heterologous expression of RoCYP resulted in increased fungal growth and improved intracellular reactive oxygen species content in R. nigricans. The $H_2O_2$ levels in RoCYP transformants were approximately 2-folder that of the R. nigricans wild type (RnWT) strain, with the superoxide dismutase activities increased approximately 45% and catalase activities decreased approximately 68%. Furthermore, the $11{\alpha}$-hydroxylation rates of EP in RoCYP transformants (C4, C6 and C9) were 39.7%, 38.3% and 38.7%, which were 12.1%, 8.2% and 9.4% higher than the rate of the RnWT strain, respectively. This paper investigated the effect of heterologous expression of RoCYP in R. nigricans, providing an effective genetic method to construct the engineered strains for steroid industry.

• Korean Journal of Veterinary Research
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• v.61 no.2
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• pp.11.1-11.5
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• 2021

To evaluate avian hepatitis E virus (aHEV) as an RNA vaccine platform, ORF2 of aHEV was replaced by heterologous genes, such as eGFP and HA-tag, in aHEV infectious cDNA clones. eGFP and HA-tag replicons were expressed in LMH cells. To confirm expression of the heterologous protein, ORF2 was replaced with the antigenic S1 gene of IBV. The IBVS1 replicon was expressed in LMH cells. To our knowledge, this is the first investigation showing the potential as a RNA vaccine platform using an aHEV. In the future, it may be used in the development of RNA vaccines against various pathogens.