• Molecules and Cells
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• 제26권4호
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• pp.362-367
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• 2008

We identified a 1,134-bp putative type III polyketide synthase from the sequence analysis of Streptomyces peucetius ATCC 27952, named Sp-RppA, which is characterized as 1,3,6,8-tetrahydroxynaphthalene synthase and shares 33% identity with SCO1206 from S. coelicolor A3(2) and 32% identity with RppA from S. griseus. The 1,3,6,8-tetrahydroxynaphthalene synthase is known to catalyze the sequential decarboxylative condensation, intramolecular cyclization, and aromatization of an oligoketide derived from five units of malonyl-CoA to give 1,3,6,8-tetrahydroxynaphthalene, which spontaneously oxidizes to form 2,5,7-trihydroxy-1,4-naphthoquinone (flaviolin). In this study, we report the in vivo expression and in vitro synthesis of flaviolin from purified gene product (Sp-RppA).

• 한국식품영양학회지
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• 제6권4호
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• pp.314-321
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• 1993

We have cloned the Bacillus cellulyticus K-12 avicelase (Avi, E.C.3.2.1.4) gene (ace A) In E. coli. This was accompanied by using the vector PT7T3U 19 and Hind W -Hind m libraries of Bacillus cellulyticus K-12 chromosomal inserts created in 5.cofi. The Libraries were screened for the expression of avicelase by monitoring the immunoreaction of the anti-avicelase (immunoscreening). Positive clones (Ac-3, Ac-5, and Ac-7) contained the identical 3.5kb Hind III fragment as determined by restriction mapping and Southern hybridization, and expressed avicelase efficiently and constituvely using its own promoter in the heterologous host. From the immunoblotting analysis, a polypeptide which showed a CMCase activity with an Mr of 54000 was detected.

• International Journal of Industrial Entomology and Biomaterials
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• 제39권1호
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• pp.22-28
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• 2019

We previously isolated 9 clones that show stronger signal compared to Bombyx mori cytoplasmic actin gene (BmA3) by using a dot blot hybridization. In this study, we focused on one clone among these clones which has high amino acid similarity with ${\beta}$-tubulin gene of B. mori. This clone was ubiquitously expressed in all tissues and developmental stage of B. mori. As result of promoter assay using dual luciferase assay system, we found the highest transcription activity region (-750/-1) in the 5'-flanking region of ${\beta}$-tubulin gene, which has about 47 fold more intensive promoter activity than BmA3 promoter. Moreover, the ${\beta}$-tubulin promoter was normally regulated in Bm5, Sf9, and S2 cells. Therefore, we suggest that ${\beta}$-tubulin promoter may be used more powerful and effectively for transgene expression in various insects containing B. mori as a universal promoter.

• Journal of Microbiology and Biotechnology
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• 제24권4호
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• pp.431-439
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• 2014

We report the construction of two Bacillus subtilis expression vectors, pBNS1/pBNS2. Both vectors are based on the strong promoter P43 and the ampicillin resistance gene expression cassette. Additionally, a fragment with the Shine-Dalgarno sequence and a multiple cloning site (BamHI, SalI, SacI, XhoI, PstI, SphI) were inserted. The coding region for the amyQ (encoding an amylase) signal peptide was fused to the promoter P43 of pBNS1 to construct the secreted expression vector pBNS2. The applicability of vectors was tested by first generating the expression vectors pBNS1-GFP/pBNS2-GFP and then detecting for green fluorescent protein gene expression. Next, the mannanase gene from B. pumilus Nsic-2 was fused to vector pBNS2 and we measured the mannanase activity in the supernatant. The mannanase total enzyme activity was 8.65 U/ml, which was 6 times higher than that of the parent strain. Our work provides a feasible way to achieve an effective transformation system for gene expression in B. subtilis and is the first report to achieve B. pumilus mannanase secretory expression in B. subtilis.

• Journal of Microbiology and Biotechnology
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• 제12권3호
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• pp.463-469
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• 2002

Rotaviruses are the world-wide leading causative agents of severe dehydrating gastroenteritis in young children and animals. The outer capsid glycoprotein VP7 and inner capsid glycoprotein VP6 of rotaviruses are highly antigenic and immunogenic. An SFV-based expression system has recently emerged as a useful tool for heterologous protein production in mammalian cells, exhibiting a much more efficient performance compared to other gene expression systems. Accordingly, the current study adopted an SFV-based expression system to express the VP7 of a group A human rotavirus from a Korean isolate, and the VP6 of a group B bovine rotavirus from a Korean isolate, in mammalian cells. The genes of the VP6 and VP7 were inserted into the SFV expression vector pSFV-1. The RNA was transcribed in vitro from pSFV-VP6 and pSFV-VP7 using SP6 polymerase. Each RNA was then electroporated into BHK-21 cells along with pSFV-helper RNA containing the structural protein gene without the packaging signal. The expression of VP6 and VP7 in the cytoplasm was then detected by immunocytochemistry. The recombinant virus was harvested by ultracentrifugation and examined under electron microscopy. After infecting BHK-21 cells with the defective viruses, the expressed proteins were separated by SDS-PAGE and analyzed by a Western blot. The results indicate that an SFV-based expression system fur the VP6 and VP7 of rotaviruses is an efficient tool for developing a diagnostic kit and/or preventive vaccine.

• BMB Reports
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• 제28권1호
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• pp.57-61
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• 1995

The expression of a recombinant human lactoferrin is reported in mouse HC11 mammary epithelial cells. Expression of human lactoferrin (hLF) was achieved by placing its cDNA under the control of the bovine ${\beta}$-casein gene. To improve the hLF expression level in a cell culture system, two artificial introns were also introduced to construct expression vectors. One intron was a hybrid-splice signal consisting of bovine ${\beta}$-casein intron 1 and rabbit ${\beta}$-globin intron II. The other intron was a DNA fragment spanning intron 8 of the bovine ${\beta}$-casein gene. The hybrid intron moderately elevated hLF expression, whereas intron 8 alone did not express any detectable amount of hLF as judged by Northem and Western blot analyses. When the two introns were used together they contributed to a synergistic elevation of hLF expression. These data indicate that artificial introns on both sides of the hLF cDNA were necessary to increase expression of cDNA.

• KSBB Journal
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• 제17권2호
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• pp.162-168
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• 2002

본 연구에서는 유도성 promoter인 GAL1과 상시성 promoter인 GPD와 ADH1 promoter 하류에 사람 ferritin H-chain 유전자(hfL) 및 사람 ferritin L-chain 유전자(hfL)를 연결하여 재조합 plasmid를 구축하고 이들을 S. cerevisiae 2805에 형질 전환시켜 외래 유전자를 성공적으로 발현시켰다. Ferritin 발현에 미치는 promoter의 영향을 비교한 바, 이 두 단백질 생간에 있어서 GAL1 promoter가 GPD나 ABH1 promoter 보다 더 효율적이었다. GAL1 promoter를 사용한 형질 전환체 (YG-H와 YG-L)에서 H-chain의 발현율은 전체 수용성 단백질 중 4.5%에 해당하였고, L-chain의 발현율은 9.8%에 이르렀다. 각 균주에서 발현된 H 및 L subunit은 비변성 젤은 사용한 전기 영동의 결과 대장균에서 생산된 재조합 단백질과 마찬가지로 자발적으로 holoprotein으로 조합되어졌다. 재조합 H-와 L-ferritin들은 단백질 내공에 철을 축적할 수 있음이 Prussian blue 염색으로 확인되었다. 그리고 효모 세포를 10 mM ferric citrate를 함유한 배지에서 배양했을 때, H-ferritin과 L-ferritin을 생산하는 재조합 효모 균주에 있어서의 펄의 농도는 각각 174.9 $\mu\textrm{g}$ Per gram(dry cell weight)과 148.8 $\mu\textrm{g}$ Per gram(dry cell weight)이었고 야생형 효모 균주에 있어서의 털의 농도는 49.4 $\mu\textrm{g}$ Per gram(dry cell weight)이었다. 이것은 사람 ferritin 유전자를 효모 균주에 발현시킴으로써 효모의 철 함량이 증진되었음을 유추하는 결과이다.

• International Journal of Industrial Entomology and Biomaterials
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• 제26권2호
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• pp.119-123
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• 2013

The insect baculovirus expression vector system (BEVS) is useful for producing biologically active recombinant proteins. However, the overexpression of heterologous proteins using this system often results in misfolded proteins and the formation of protein aggregates. To overcome this limitation, we developed a versatile baculovirus expression and secretion system using Bombyx mori protein disulfide isomerase (bPDI) as a fusion partner. bPDI gene fusion was found to improve the secretions and antibacterial activities of recombinant nuecin and enbocin proteins. Thus, we conclude that bPDI gene fusion is a useful addition to BEVS for the large-scale production of bioactive recombinant proteins.

• 한국미생물·생명공학회지
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• 제24권3호
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• pp.290-298
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• 1996

In an effort to understand the role of the conserved domain and of the heterologous one-third part of the carboxy terminal domain of transglutaminase C (TGase II), attempts were made to express TGase II cDNA of human origin in yeast Saccharomyces cerevisiae as in a full-length form as well as in a form of C-terminal truncation. The 2$\mu$-based expression plasmids which contained the TGase II cDNA under the gal inducible promoter were introduced into yeast and the maintenance of the full-length and truncated form of the TGase II gene plasmids were confirmed by Southern blot. The expression of the TGase II gene was analysed by reverse transcription polymerase chain reaction (RT-PCR), and western blot analyses. As assayed by [1,4$^{14}$C]-putrescine incorporation into succinylated casein, the full-lenth as well as the truncated forms of recombinant TGase II showed some catalytic activity. These results indicate that the N-terminal homologous domain of human TGase II retains a catalytically active domain. The level of TGase II expressed in yeast, however, was far lower than satisfactory and other expression system should be sought further chracterization of the enzyme. The negative effect of TGase II on the growth of yeast is interesting with respect to the physiological effect of TGase II in cornification of epidermal keratinocytes.

• Journal of Microbiology and Biotechnology
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• 제29권11호
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• pp.1790-1798
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• 2019

Flock House virus (FHV), an insect RNA virus, has a bipartite genome. FHV RNA1 can be packaged in turnip yellow mosaic virus (TYMV) as long as the FHV RNA has a TYMV sequence at the 3'-end. The encapsidated FHV RNA1 has four additional nucleotides at the 5'-end. We investigated whether the recombinant FHV RNA1 could replicate in mammalian cells. To address this issue, we prepared in vitro transcribed FHV RNAs that mimicked the recombinant FHV RNA1, and introduced them into baby hamster kidney (BHK) cells. The result showed that the recombinant FHV RNA1 was capable of replication. An eGFP gene inserted into the frame with B2 gene of the FHV RNA1 was also successfully expressed. We also observed that eGFP expression at the protein level was strong at 28℃ but weak at 30℃. Sequence analysis showed that the 3'-ends of the RNA1 and RNA3 replication products were identical to those of the authentic FHV RNAs. This indicates that FHV replicase correctly recognized an internally-located replication signal. In contrast, the 5'-ends of recombinant FHV RNA1 frequently had deletions, indicating random initiation of (+)-strand synthesis.