• 한국동물학회지
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• 제33권3호
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• pp.303-309
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• 1990

대장균에서 진핵세포의 펩타이드 호르몬 전구체를 대량으로 생산할 목적으로 T7 overexpression system을 이용하여 angler 어류의 prepro-SRIF I 유전자와 T7 phage coat 단백질 S10 유전자를 결합시켜 일련의 융합유전자를 합성하였다. 이 융합유전자를 가지고 있는 숙주 대장균, BL21 DE3는 3가지 종류의 서로 다른 SRIF 관련 폴리펩타이드를 대량 합성하였다. 본 연구에서는 대량합성된 폴리펩타이드의 특성을 규명하였으며, 펩타이드 호르몬 전구체를 얻기 어려운 이종이에서의 대량발현의 중요성과 표적 펩타이드 호르몬인 SRIF의 적용성을 논의하였다.

• Journal of Microbiology and Biotechnology
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• 제27권7호
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• pp.1345-1358
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• 2017

The impact of overproduction of a heterologous protein on the metabolic system of host Lactococcus lactis was investigated. The protein expression profiles of L. lactis IL1403 containing two near-identical plasmids that expressed high- and low-level of the green fluorescent protein (GFP) were examined via shotgun proteomics. Analysis of the two strains via high-throughput LC-MS/MS proteomics identified the expression of 294 proteins. The relative amount of each protein in the proteome of both strains was determined by label-free quantification using the spectral counting method. Although expression level of most proteins were similar, several significant alterations in metabolic network were identified in the high GFP-producing strain. These changes include alterations in the pyruvate fermentation pathway, oxidative pentose phosphate pathway, and de novo synthesis pathway for pyrimidine RNA. Expression of enzymes for the synthesis of dTDP-rhamnose and N-acetylglucosamine from glucose was suppressed in the high GFP strain. In addition, enzymes involved in the amino acid synthesis or interconversion pathway were downregulated. The most noticeable changes in the high GFP-producing strain were a 3.4-fold increase in the expression of stress response and chaperone proteins and increase of caseinolytic peptidase family proteins. Characterization of these host expression changes witnessed during overexpression of GFP was might suggested the metabolic requirements and networks that may limit protein expression, and will aid in the future development of lactococcal hosts to produce more heterologous protein.

• BMB Reports
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• 제42권2호
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• pp.113-118
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• 2009

Despite the growing body of evidence suggesting a role for MsrA in antioxidant defense, little is currently known regarding the function of MsrB in cellular protection against oxidative stress. In this study, we overexpressed the mammalian MsrB and MsrA genes in Saccharomyces cerevisiae and assessed their subcellular localization and antioxidant functions. We found that the mitochondrial MsrB3 protein (MsrB3B) was localized to the cytosol, but not to the mitochondria, of the yeast cells. The mitochondrial MsrB2 protein was detected in the mitochondria and, to a lesser extent, the cytosol of the yeast cells. In this study, we report the first evidence that MsrB3 overexpression in yeast cells protected them against $H_2O_2$-mediated cell death. Additionally, MsrB2 overexpression also provided yeast cells with resistance to oxidative stress, as did MsrA overexpression. Our results show that mammalian MsrB and MsrA proteins perform crucial functions in protection against oxidative stress in lower eukaryotic yeast cells.

• Journal of Microbiology and Biotechnology
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• 제24권9호
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• pp.1238-1244
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• 2014

Dephosphocoenzyme A (CoaE) catalyzes the last step in the biosynthesis of the cofactor coenzyme A. In this study, we report the identification and application of CoaE from Stretomyces peucetius ATCC27952. After expression of coaE, the protein was found to have a molecular mass of 28.6 kDa. Purification of the His-tagged fused CoaE protein was done by immobilized metal-affinity chromatography, and then in vitro enzymatic coupling assay was performed. The increasing NADH consumption with time shed light on the phosphorylating activity of CoaE. Furthermore, the overexpression of coaA and coaE independently under the $ermE^*$ promoter in the doxorubicin -producing wild type strain, resulted in 1.4- and 1.5-fold enhancements in doxorubicin production, respectively. In addition, the overexpression of both genes together showed a 2.1-fold increase in doxorubicin production. These results established a positive role for secondary metabolite production from Streptomyces peucetius.

• Journal of Microbiology and Biotechnology
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• 제26권1호
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• pp.66-71
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• 2016

PikD is a widely known pathway-specific regulator for controlling pikromycin production in Streptomyces venezuelae ATCC 15439, which is a representative of the large ATP-binding regulator of the LuxR family (LAL) in Streptomyces sp. RapH and FkbN also belong to the LAL family of transcriptional regulators, which show greatest homology with the ATP-binding motif and helix-turn-helix DNA-binding motif of PikD. Overexpression of pikD and heterologous expression of rapH and fkbN led to enhanced production of pikromycin by approximately 1.8-, 1.6-, and 1.6-fold in S. venezuelae, respectively. Cross-complementation of rapH and fkbN in the pikD deletion mutant (ΔpikD) restored pikromycin and derived macrolactone production. Overall, these results show that heterologous expression of rapH and fkbN leads to the overproduction of pikromycin and its congeners from the pikromycin biosynthetic pathway in S. venezuelae, and they have the same functionality as the pathwayspecific transcriptional activator for the pikromycin biosynthetic pathway in the ΔpikD strain. These results also show extensive "cross-communication" between pathway-specific regulators of streptomycetes and suggest revision of the current paradigm for pathwayspecific versus global regulation of secondary metabolism in Streptomyces species.

• Journal of Microbiology and Biotechnology
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• 제14권6호
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• pp.1350-1355
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• 2004

The sprA and sprB genes, encoding the chymotrypsin-like proteases Streptomyces griseus protease A (SGPA) and Streptomyces griseus protease B (SGPB), and the sprT gene that encodes Streptomyces griseus trypsin (SGT) were cloned from S. griseus and were overexpressed in various strains of S. griseus. When the sprT gene was introduced into S. griseus, trypsin activity increased 2-fold in the A-factor deficient mutant strain, S. griseus HH1, and increased 4-fold in the wild strain, S. grise us IFO 13350. However, there was no detectable increase of chymotrypsin activity in the transformants of S. griseus with either sprA or sprB, in contrast to the results obtained from S. lividans as a heterologous host. To solve the negative gene dosage effects in S. griseus, either the sprA or the sprB genes with their own ribosome binding sites were linked to the downstream of the entire sprT gene, and the coexpression efficiency was examined in S. lividans and S. griseus. The transformants of S. lividans with either pWHM3-TA (sprT+sprA) or pWHM3­TB (sprT+sprB) showed 3-fold increase of trypsin activity over that of the control, however, only the transformant of pWHM3-TB demonstrated 7-fold increase in chymotrypsin activity, indicating that the pWHM3-TB has a successful construction for the overexpression of chymotrypsin in Streptomyces. When the coexpression vectors were introduced into S. griseus IFO 13350, the trypsin level sharply increased by more than 4-fold, however, the chymotrypsin level did not increase. These results strongly suggest that the overexpression of the sprA and sprB genes is tightly regulated in S. griseus.

• Journal of Microbiology
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• 제39권4호
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• pp.305-313
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• 2001

The spr D gene encoding Strptomyces griseus protease D(SGPD); a chymotrypsin-like proteae, was cloned from Strptomyces griseus IFO13350 and sequence. Most of the amino-acid sequence deduced from the nucleotide sequence is idential to that Strptomyces griseus IMRU3499 except that one amino acid has been deleted and Trp 369 has been substituted into Cys369 in the SGPD from S. griseus IFO13350 without affecting the protease activity. The spr D gene was overexpressed in Streptomyce liv-idans TK24 as a heterologous host. Various media with different compositions were also used to max-imize the productivity of SGPD inthe heterologous host. The SGPD productivity was best when the transformant S. lividans TK24 was cultivated in R2YE medium. The relative chymotrypsin activity of the culture broth measured with an artificial chromogenic substrate, N-scuccinyl-ala-ala-pro-phe-p-nitroanilide, was 16 units/ml. A high level of SGPD was also produced in YEME and SAAM medial but it was relatively lower that in R2YE medium and negligible amounts of SGPD were produced in GYE, GAE and Benedict media. The growth of S. lividans reacted the maximum level of cell mass at days 3 and 4 of the culture, but SGPD production started in the stationary phase of cell growth and kept increase in till the 10$^{th}$ day of culture in R2YE and YEME medium, but in GYE media the productivity reached maximum level at 8days of cultivation. The introduction of the spr D gene into S. lividans TK24 triggered biosyntheis of the pigmented antibiotic , actinorhodin, which implies some protease may paly a very improtant role in secondary-metabolite formation in sStreptomyces.

• Journal of Microbiology and Biotechnology
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• 제9권4호
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• pp.488-497
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• 1999

Probing Streptomyces albus ATCC 21838 chromosomal DNA with a proline tRNA sequence resulted in an isolation of a putative integrating element in the 6.4-kb EcoRI fragment. It was found that Streptomyces lividans TK-24 transformed with a cloned DNA fragment on a multicopy plasmid, produced a higher level of spore pigment and mycelial red pigment on a regeneration agar. Furthermore, the transformant S. lividans TK-24 produced a markedly increased level of undecylprodigiosin in a broth culture. A nucleotide sequence analysis of the cloned region revealed several open reading frames homologous to the integrases of integrating plasmids or temperate bacteriophages, signal-transducing regulatory proteins with a conserved ATP-binding domain, oxidoreductases ($\beta$-ketoacyl reductase), and an AraC-like transcriptional regulator. To examine the effect on antibiotic production, each coding region was overexpressed separately from the other genes in the region in S. lividans TK-24 with; pJHS3044 for the expression of the signal-transducing regulatory protein homologue, pJHS3045 for the homologue of oxidoreductase, and pJHS3051 for the homologue of the AraC-like transcriptional regulator. Phenotypic studies of S. lividans TK-24 strains harboring plasmids for the overexpression of individual genes suggested the following effects of the genes on antibiotic production: The oxidoreductase homologue stimulated the production of actinorhodin and undecylprodigiosin, which was influenced by the culture conditions; the homologue of the AraC-like transcriptional regulator was the most effective factor in antibiotic production within all the culture conditions tested; the signal-transducing regulatory protein homologue repressed the effect due to the homologue of the AraC-like transcriptional regulator, however, the antibiotic production was derepressed upon entering the stationary phase.

• Journal of Ginseng Research
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• 제41권3호
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• pp.419-427
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• 2017

Background: Glycosylation of natural compounds increases the diversity of secondary metabolites. Glycosylation steps are implicated not only in plant growth and development, but also in plant defense responses. Although the activities of uridine-dependent glycosyltransferases (UGTs) have long been recognized, and genes encoding them in several higher plants have been identified, the specific functions of UGTs in planta remain largely unknown. Methods: Spatial and temporal patterns of gene expression were analyzed by quantitative reverse transcription (qRT)-polymerase chain reaction (PCR) and GUS histochemical assay. In planta transformation in heterologous Arabidopsis was generated by floral dipping using Agrobacterium tumefaciens (C58C1). Protein localization was analyzed by confocal microscopy via fluorescent protein tagging. Results: PgUGT72AL1 was highly expressed in the rhizome, upper root, and youngest leaf compared with the other organs. GUS staining of the promoter: GUS fusion revealed high expression in different organs, including axillary leaf branch. Overexpression of PgUGT72AL1 resulted in a fused organ in the axillary leaf branch. Conclusion: PgUGT72AL1, which is phylogenetically close to PgUGT71A27, is involved in the production of ginsenoside compound K. Considering that compound K is not reported in raw ginseng material, further characterization of this gene may shed light on the biological function of ginsenosides in ginseng plant growth and development. The organ fusion phenotype could be caused by the defective growth of cells in the boundary region, commonly regulated by phytohormones such as auxins or brassinosteroids, and requires further analysis.

• Journal of Ginseng Research
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• 제43권4호
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• pp.645-653
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• 2019

Background: Cytochrome P450 enzymes catalyze a wide range of reactions in plant metabolism. Besides their physiological functions on primary and secondary metabolites, P450s are also involved in herbicide detoxification via hydroxylation or dealkylation. Ginseng as a perennial plant offers more sustainable solutions to herbicide resistance. Methods: Tissue-specific gene expression and differentially modulated transcripts were monitored by quantitative real-time polymerase chain reaction. As a tool to evaluate the function of PgCYP736A12, the 35S promoter was used to overexpress the gene in Arabidopsis. Protein localization was visualized using confocal microscopy by tagging the fluorescent protein. Tolerance to herbicides was analyzed by growing seeds and seedlings on Murashige and Skoog medium containing chlorotoluron. Results: The expression of PgCYP736A12 was three-fold more in leaves compared with other tissues from two-year-old ginseng plants. Transcript levels were similarly upregulated by treatment with abscisic acid, hydrogen peroxide, and NaCl, the highest being with salicylic acid. Jasmonic acid treatment did not alter the mRNA levels of PgCYP736A12. Transgenic lines displayed slightly reduced plant height and were able to tolerate the herbicide chlorotoluron. Reduced stem elongation might be correlated with increased expression of genes involved in bioconversion of gibberellin to inactive forms. PgCYP736A12 protein localized to the cytoplasm and nucleus. Conclusion: PgCYP736A12 does not respond to the well-known secondary metabolite elicitor jasmonic acid, which suggests that it may not function in ginsenoside biosynthesis. Heterologous overexpression of PgCYP736A12 reveals that this gene is actually involved in herbicide metabolism.