• International Journal of Industrial Entomology and Biomaterials
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• 제19권1호
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• pp.199-204
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• 2009

The newly cloned Bacillus thuringiensis cry1-5 gene showed high activity to both Plutella xylostella and Spodoptera exigua, while cry1Ac only showed high activity against P. xylostella but low to S. exigua. Through the alignment of amino acid sequences between Cry1Ac and Cry1-5, we found 12 different residues in domain I (6 residues) and domain II (6 residues). In this study, the modified cry1Ac gene, which is constructed according to a crop-preferring codon usage, was used as a template to construct mutant B. thuringiensis cry1Ac genes based on cry1-5 gene through multi site-directed mutagenesis. Total 63 various mutant cry genes were obtained at 12 positions randomly. Among them, ten mutant cry genes, whose domain I was totally converted and domain II was randomly, were selected to express in baculovirus expression system as a polyhedrin fusion form. The recombinant proteins were 95 kDa in size and were stably activated as 65 kDa by trypsin. The expressed mutant Cry proteins were applied to bioassays against P. xylostella and S. exigua. All mutants showed high insecticidal activity both to P. xylostella and S. exigua similar to cry1-5. These results suggest that these mutant cry genes might be expected of desirable cry genes for introduction to transgenic crops.

• Journal of Microbiology and Biotechnology
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• 제17권1호
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• pp.15-20
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• 2007

To clone novel cry1-type genes from the Bacillus thuringiensis K1 isolate, about 2.4-kb-long PCR fragments were amplified with two primer sets of ATG1-F/N400-R and 1BeATG1-F/N400-R. Using PCR-RFLP, three novel cry1-type genes, cry1-1, cry1-7, and cry1-44, were obtained from B. thuringiensis K1 and the complete coding sequences of these novel genes were analyzed. The Cry1-1, Cry1-7, and Cry1-44 proteins showed maximum similarities of about 78.0%, 99.7%, and 91.0% with the Cry1Ha1, Cry1Be1, and Cry1Ac2 proteins, respectively. These novel cry1-type genes were expressed using a baculovirus expression vector system and their insecticidal activities were investigated. Whereas all three novel genes were toxic to Plutella xylostella larvae, only Cry1-1 showed insecticidal activity against Spodoptera exigua larvae.

• Journal of Microbiology and Biotechnology
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• 제11권3호
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• pp.482-490
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• 2001

The gene for glycoprotein B (gB2) of HSV-2-strain G was subcloned, sequenced, recombinated into the lacZ-HcNPV, expressed in insect cells, and compared with the homologous gene of other HSV-2 strains. The ORF of the gB2 gene was 2,715 bp. The overall nucleotide sequence homology of te gB2 gene compared ith that of the two previously reported HSV-2 strains appeared to be over 98%. A recombinant virus named Baculo-gB2 protein in insect cells. The recombination was confirmed by a PCR and the expression was demonstrated by radio immunoprecipitation. Insect cells infected with the Baculo-gB2 virus synthesized and processed gB2 with approximately 120 kDa in the cells, and then secreted it into the culture media, where it reacted with a nomoclonal antibody to gB2. The gB2 polypeptide contained two main hydrophobic regions (a signal sequence from 1 to 23 amino acid residues, and a membrane anchor sequence from aa 745 to 798), eight N-glycosylation sites evenly distributed, and was rich in alanine (11.2%). Antibodies to this recombinant protein that were raised in mice recognized the viral gB2 and neutralized the infectivity of the HSV-2 in vitro. There results show that the gB2 protein was successfully porduced in insect cells and could be used to raise a protective neutralizing antibody. Accordingly, this particular recombinant protein may be useful in the development of a subunit vaccine.

• Journal of Microbiology and Biotechnology
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• 제25권3호
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• pp.386-392
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• 2015

A novel recombinant bacmid, bEasyBm, that enables the easy and fast generation of pure recombinant baculovirus without any purification step was constructed. In bEasyBm, attR recombination sites were introduced to facilitate the generation of a recombinant viral genome by in vitro transposition. Moreover, the extracellular RNase gene from Bacillus amyloliquefaciens, barnase, was expressed under the control of the Cotesia plutellae bracovirus early promoter to negatively select against the nonrecombinant background. The bEasyBm bacmid could only replicate in host insect cells when the barnase gene was replaced with the gene of interest by in vitro transposition. When bEasyBm was transposed with pDualBac-EGFP, the resulting recombinant virus, EasyBm-EGFP, showed high levels of EGFP expression efficiency compared with that of non-purified recombinant virus BmGOZA-EGFP, which was constructed using the bBmGOZA system. In addition, nonrecombinant backgrounds were not detected in unpurified EasyBm-EGFP stocks. Based on these results, a high-throughput system for the generation of multiple recombinant viruses at a time was established.

• Journal of Microbiology and Biotechnology
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• 제18권2호
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• pp.383-391
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• 2008

The glycans linked to the insect cell-derived glycoproteins are known to differ from those expressed in mammalian cells, partly because of the low level or lack of glycosyltransferase activities. GnT II, GnT IV, GnT V, and ST3Gal IV, which play important roles in the synthesis of tetraantennarytype complex glycan structures in mammalian cells, were overexpressed in Trichoplusia ni cells by using a baculovirus expression vector. The glycosyltransferases, expressed as a fusion form with the IgG-binding domain, were secreted into the culture media and purified using IgG sepharose resin. The enzyme assay, performed using a pyridylaminated-sugar chain as an acceptor, indicated that the purified glycosyltransferases retained their enzyme activities. Human erythropoietin expressed in T. ni cells (rhEPO) was subjected to in vitro glycosylation by using recombinant glycosyltransferases and was converted into complex-type glycan with terminal sialic acid. The presence of Nacetylglucosamine, galactose, and sialic acid on the rhEPO moiety was detected by a lectin blot analysis, and the addition of galactose and sialic acid to rhEPO was confirmed by autoradiography using $UDP-^{14}C-Gal\;and\;CMP-^{14}C-Sia$ as donors. The in vitro glycosylated rhEPO was injected into mice, and the number of reticulocytes among the ed blood cells was counted using FACS. A significant increase in the number of reticulocytes was not observed in the mice injected with in vitro glycosylated rhEPO as compared with those injected with rhEPO.

• Animal cells and systems
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• 제11권2호
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• pp.175-182
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• 2007

The lysozyme II gene of cabbage butterfly Artogeia rapae was cloned from fat body of the larvae injected with E. coli and its nucleotide sequence was determined by the RACE-PCR. It has an open reading frame of 414 bp nucleotides corresponding to 138 amino acids including a signal sequence of 18 amino acids. The estimated molecular weight and the isoelectric point of the lysozyme II without the signal peptide were 13,649.38 Da and 9.11, respectively. The A. rapae lysozyme II (ARL II) showed the highest identity (81%) in the amino acid sequence to Manduca sexta lysozyme among other lepidopteran species. The two catalytic residues ($Glu^{32}$ and $Asp^{50}$) and the eight Cys residue motifs, which are highly conserved among other c-type lysozymes in invertebrates and vertebrates, are also completely conserved. A phylogenetic analysis based on amino acid sequences indicated that the ARL II was more closely related to M. sexta, Hyphantria cunea, Heliothis virescens, and Trichoplusia ni lysozymes. The ARL II gene was expressed in Spodoptera frugiperda 21 insect cells and the recombinant ARL II (rARL II) was purified from cell-conditioned media by cation exchange column chromatography and reverse phase FPLC. The purified rARL II was able to form a clear zone in lysoplate assay against Micrococcus luteus. The lytic activity was estimated to be 511.41 U/mg, 1.53 times higher than that of the chicken lysozyme. The optimum temperature for the lytic activity of the rARL II was $50^{\circ}C$, the temperature dependency of the absolute lytic activity of rARL II was higher than that of the chicken lysozyme at low temperatures under $65^{\circ}C$.

• BMB Reports
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• 제33권6호
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• pp.483-492
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• 2000

The Herpes simplex virus type 1 (HSV-1) strain F glycoprotein H (gH) gene in the pHLB-4 plasmid was recombinated into a baculovirus expression vector (lacZ-HcNPV) to construct a recombinant virus GH-HcNPV expressing gH. The sequences of gH and its expression were analyzed. The gH gene was located in the 6.41 kb BglII fragment. The open reading frame (ORF) of the gH gene was 2,517 bp and codes 838 amino acid residues. Insect cells infected with this recombinant virus synthesized a high level of the matured and gX-gH fusion protein with approximately 112 kDa. The fusion gH protein was localized on the membrane of the insect cells as seen by using immunofluorescence assay and accumulated in the cultured media by the SDS-PAGE and immunoprecipitation assays. The amino acid sequence presents additional characteristics compatible with the structure of a viral glycoprotein: signal peptide, putative glycosylation sites and a long C-terminal transmembrane sequence. Antibodies raised in mice to this recombinant protein recognized viral gH and neutralized the infectivity of HSV-1 in vitro. These results demonstrate that it is possible to produce a mature protein by gene transfer in eukaryotic cells, and indicate the utility of the HcNPV-insect cell system for producing and characterizing eukaryotic proteins. Furthermore, the neutralizing antibodies would appear to protect mice against HSV; accordingly, this particular recombinant protein may be useful in the development of a subunit vaccine.

• 생명과학회지
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• 제24권1호
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• pp.86-91
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• 2014

Trichoplusia ni (T. ni) 세포는 사람 당 수송체를 이성질적으로 많은 양 생산하려 할 때 유용하게 사용되는, baculovirus 발현 시스템의 숙주세포로서 이용된다. 그러나 T. ni 세포에 존재하는 내재된 당 수송체의 높은 활동은, 발현된 외재적 당 수송체의 수송활성과 같은 직접적 증거 제시에 장애가 된다. 뿐만 아니라 곤충세포에 내재하는 당 수송체계의 특성에 대해서는 밝혀진 바가 거의 없다. 그래서 본 연구에서는 baculovirus 발현 시스템을 보다 잘 활용하기 위해 T. ni 세포의 2dGlc기질 수송에 D-fructose가 미치는 영향을 살펴 보았으며, T. ni 세포에 발현된 사람 당 수송체의 생물학적 활성을 보다 용이하게 검증하기 위해 발현된 수송체를 [$^3H$] cytochalasin B를 이용하여 photolabelling 하였다. 우선 감염되지 않은 세포와 recombinant AcMPV-GTL 감염시킨 T. ni 세포의 2dGlc uptake를 300 mM D-fructose가 있을 때와 없을 때, 그리고 $20{\mu}M$ cytochalasin B가 있을 때와 없을 때의 상황에서 살펴보았다. 감염되지 않은 세포에서의 육탄당 uptake는 D-fructose에 의해 강력하게 억제 되었으나 cytochalasin B에 의해서는 단지 미미한 억제 효과만을 보여주었다. 흥미롭게도 AcMPV-GTL 바이러스 감염된 T. ni 세포에서는 비록 2dGlc uptake율은 감염되지 않은 세포와 비교해 다소 낮았지만 육탄당 수송 억제 반응은 근본적으로 동일함을 보여 주었다. 또한 [$^3H$] cytochalasin B를 이용한 발현단백질 photolabelling에서는, L-glucose가 존재하는 상황 하에만 하나의 날카롭게 표지된 peak가, 바이러스 감염된 세포에서 관찰되었다. 감염되지 않은 세포에서는 이러한 peak는 관찰되지 않았다. 게다가 D-glucose 존재 하에서는 발현된 단백질의 photolabelling이 완전히 억제되어짐을 보여주어, labelling의 입체선택성(stereoselectivity)을 입증하였다.

• 대한수의학회지
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• 제42권1호
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• pp.89-100
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• 2002

The nonstructural glycoprotein NSP4, encoded by the 10th gene of rotavirus, has been known to play important roles in viral assembly and pathogenesis. The NSP4 genes of human rotavirus Korean isolates, designated as CBNU/HR-1, CBNU/HR-2, CBNU/HR-3, and CBNU/HR-4, were cloned, sequenced and characterized. Also, the NSP4 gene of the CBNU/HR-1 was expressed in a baculovirus-insect cell system. The sequence data indicated that the NSP4 genes of human rotavirus Korean isolates were 750 or 751 bases in length and encoded one open reading frame of 175 amino acids. Two glycosylation sites were recognized in the NSP4 gene of human rotavirus isolates tested. The NSP4 of CBNU/HR-1, CBNU/HR-3, and CBNU/HR-4 exhibited a high degree of amino acid sequence homology with that of NSP4 genotype B viruses, but a low degree of amino acid sequence homology with that of NSP4 genotype A viruses. However, the NSP4 of CBNU/HR-2 exhibited a high degree of amino acid sequence homology with that of NSP4 genotype A viruses, but a low degree of amino acid sequence homology with that of NSP4 genotype B viruses. The Sf9 cells infected with recombinant baculovirus, inserted with NSP4 gene of CBNU/HR-1, produced specific cytopathic effects and the expressed NSP4 was detected by immunofluorescence staining using NSP4-specific monoclonal antibody(MAb). The expressed NSP4 migrated at 16-26 kDa on SDS-PAGE and reacted with NSP4-specific MAb by Western blotting.

• International Journal of Industrial Entomology and Biomaterials
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• 제19권2호
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• pp.259-264
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• 2009

The AvChit gene encodes for a chitinase from the spider, Araneus ventricosus. This spider, A. ventricosus, is an abundant species in Korea. Arabidopsis thaliana plants were transformed with the AvChit gene using Agrobacterium tumefaciens. Thirteen transgenic lines expressing the AvChit gene were obtained. Functional expression of the AvChit gene in transgenic Arabidopsis was confirmed by Southern, northern and western blot analysis. The AvChit cDNA was expressed as a 61 kDa polypeptide in baculovirus-infected insect Sf9 cells. AvChit protein extracted from transgenic Arabidopsis exhibited high levels of chitinase activity. Phytopathological tests showed that two transgenic Arabidopsis lines expressing the AvChit gene displayed high levels of resistance to gray mold disease (Botrytis cinerea).