• Journal of Microbiology and Biotechnology
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• 제30권9호
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• pp.1273-1281
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• 2020

Due to the broad host suitability of viral vectors and their high gene delivery capacity, many researchers are focusing on viral vector-mediated gene therapy. Among the retroviruses, foamy viruses have been considered potential gene therapy vectors because of their non-pathogenicity. To date, the prototype foamy virus is the only retrovirus that has a high-resolution structure of intasomes, nucleoprotein complexes formed by integrase, and viral DNA. The integration of viral DNA into the host chromosome is an essential step for viral vector development. This process is mediated by virally encoded integrase, which catalyzes unique chemical reactions. Additionally, recent studies on foamy virus integrase elucidated the catalytic functions of its three distinct domains and their effect on viral pathogenicity. This review focuses on recent advancements in biochemical, structural, and functional studies of foamy virus integrase for gene therapy vector research.

• 한국가축번식학회지
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• 제21권4호
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• pp.397-403
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• 1997

Retrovirus vector를 이용한 형질전환 동물의 생산에 있어서 시급히 선행되어야 할 가장 중요한 요소는 표적세포에 대해 높은 감염도를 가진 virus를 생산하는 system의 개발이다. 이러한 문제를 해결하기 위한 일환으로 본 연구에서는 세 가지 방법을 사용하여 세포 배양액 속의 virus의 농도를 높여줌으로써 retrovirus vector system에서 생산되는 virus의 낮은 감염도를 극복하고자 하였다. 이 실험에서 얻어진 결과는 다음과 같다. 1) Virus를 생산하는 세포(pG13-LN$\beta$Z retrovirus producing cell)를 5mM의 Na-butyrate로 처리했을 때 virus titer는 소의 embryonic trachea 표적세포에서 약 3배의 증가를 나타냈다. 2) Virus가 들어있는 세포 배양액을 ultrafiltration을 통해 농축한 결과, 농축액 속의 virus titer는 대조구에 비해 약 3.6배 증가하였다. 3) 초원심분리를 통해 농축된 virus stock의 titer는 소의 embryonic trachea 표적세포에서 약 1.0$\times$105LacZ+TU/ml였는데 이 방법은 대조구에 비해 약 12.5배 만큼의 titer의 향상을 가져왔다. 따라서, 이와같이 농축된 virus stock을 이용할 경우 retrovirus vector system을 이용한 소의 수정란에의 유전자 전이율을 현저히 향상시킬 수 있으리라 사료된다.

• Journal of Plant Biotechnology
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• 제7권3호
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• pp.143-148
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• 2005

The coat protein mediated resistance to potato virus Y is assessed here in transgenic potato plants (Solanum tuberosum L., cv Claustar). Therefore, the corresponding cDNA from tunisian isolate of the virus was cloned into Agrobacterium tumefaciens binary vector. The transgenic lines were subsequently analysed for the presence and expression of the transgene. The CP cDNA copy number was determined for kanamycin resistant plants. Three selected transgenic lines and their S1 progeny resulting from tuber germination showed a high protection level against the virus. These data appear to support the hypothesis that the virus resistance is mediated by the translated viral coat protein expressed in transgenic potato lines.

• 한국가축번식학회지
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• 제25권2호
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• pp.171-180
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• 2001

형질전환 가금의 생산에 있어서 retrovirus vector를 이용하는 방법은 다양한 종류의 표적세포에 대하여 retrovirus 고유의 감염성에 의한 외래 유전자의 전이가 용이하고, 전이된 유전자가 진정염색질 영역 내로 선택적으로 도입될 수 있으며 유전적으로 안정성을 나타내므로 매우 효과적인 방법이다. 그러나 가금에서는 초기 배발달에 의한 급격한 세포의 수적 증가로 인해 고감염성의 virus의 획득이 요구되므로, 이를 위하여 virus stock의 농축에 있어 보다 안정적이고 pantropic인 vesicular stomatitis virus (VSV G) glycoprotein를 envelope로 가지는 pseudotyped retrovirus vector system을 이용하였으며, marker gene으로 eGFP gene이 발현되는 retrovirus를 생산하였다. 이 virus를 이용하여 여러 가지 표적세포와 primary culture한 CEF세포를 감염시켜 GFP의 발현을 확인하였으며, 농축한 virus stock은 stage X의 계란을 선택하여 windowed egg를 제작한 후 배하층에 주입하였다. 형질전환 닭은 정상 발생한 닭에 비하여 저조한 발생율을 보였으나 PCR을 이용하여 외래 유전자의 도입을 확인한 결과 100%인 것으로 나타났다. 또한 한 개체 내에서 유전자의 도입이 폐, 간, 정소, 소장 등의 여러 장기에서 확인되었다.

• BMB Reports
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• 제38권1호
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• pp.41-48
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• 2005

In this study we developed the transposon-mediated shuttle vector 'Hanpvid', which composed of HaNPV (Heliothis armigera nuclear polyhedrosis virus) genomic DNA and a transposon cassette from Bacmid of Bac-to-Bac system. Hanpvid replicates in E. coli in the same way as Bacmid and retains infective function in cotton bollworm cells (Hz-AM1). Using Hanpvid we constructed a recombinant virus, which could infect Hz-AM1 cells and generate recombinant HaNPV (rHa-Bar) containing the barnase gene, a ribonuclease gene from Bacillus amyloliquefaciens. Since the expression vector carrying barnase gene cannot replicate in the absence of barstar, a specific inhibitor of barnase, we constructed a new cotton bollworm cell line (AM1-NB) using the marker rescue method. In AM1-NB barstar was integrated into the cellular chromosome to sustain the replication of rHa-Bar. To screen out recombinant HaNPV for potential use as biopesticide, Hz-AM1 and AM1-NB cell lines were infected with rHa-Bar, respectively. The results obtained indicate that Viral progenies in AM1-NB were 23 and 160 times greater than those in Hz-AM1 48 h and 72 h after infection, respectively. With additional insertion of the polyhedron gene from AcNPV (Autographa californica nuclear polyhedrosis virus) into the Hanpvid genome, rHa-Bar regained the polyhedron phenotype and its pest-killing rate greatly improved. Toxic analysis showed that the lethal dosages ($LD_{50}$) and the lethal time(s) ($LT_{50}$) of rHa-Bar were reduced by 20% and 30%, respectively, compared to wt-HaNPV in the third instar larvae of cotton bollworm. This study shows that in AM1-NB barnase can be effectively produced and used as pest-killing agent for the biological control of cotton pests.

• 대한수의학회지
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• 제29권3호
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• pp.407-416
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• 1989

The prospect of live vaccines consisting of genetically modified vaccinia virus expressing foreign genes is exciting, but important issues concerning safety and efficacy need to resolved. Vaccinia virus (VV) is an efficient expression vector with broad host range infectivity and large DNA capacity. This vector has been particularly useful for identifying target antigens for humoral and cell-mediated immunity. The WHO smallpox eradication program, involving the extensive use of VV vaccines, resulted in the late 1970s in the elimination of one of the world's most feared diseases. This achievement is a triumph for preventive medicine and for international collaboration in public health. In 1980, WHO recommended that the routine use of smallpox vaccine should be stopped. Against this background, the prospect of li ve vaccines consisting of genetically modified VV expressing foreign antigens arising from the work of Moss, and Paoletti and their colleagues in 1982 has been greeted with enthusiasm. These investigators have shown that genes coding for immunogenic proteins can be inserted into VV DNA without impairing the ability of the virus to grow in cell culture. Moreover experimental animals infected with VV recombinants containing genes coding for a variety of immunizing proteins have been shown to be protected against challenge infection with the corresponding infectious agent. In this communication, I describe current progress in the construction of a novel plasmid vector that facilitate the insertion and expression of foreign genes in VV as well as the selection of recombinants.

• BMB Reports
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• 제41권10호
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• pp.739-744
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• 2008

Turnip yellow mosaic virus (TYMV) is a positive strand RNA virus that infects mainly Cruciferae plants. In this study, the TYMV genome was modified by inserting an extra subgenomic RNA promoter and a multiple cloning site. This modified TYMV was introduced into Nicotiana benthamiana using a Agrobacterium-mediated T-DNA transfer system (agroinfiltration). When a gene encoding $\beta$-glucuronidase or green fluorescent protein was expressed using this modified TYMV as a vector, replication of the recombinant viruses, especially the virus containing $\beta$-glucuronidase gene, was severely inhibited. The suppression of replication was reduced by co-expression of viral silencing suppressor genes, such as tombusviral p19, closteroviral p21 or potyviral HC-Pro. As expected, two subgenomic RNAs were produced from the recombinant TYMV, where the larger one contained the foreign gene. An RNase protection assay revealed that the recombinant subgenomic RNA was encapsidated as efficiently as the genuine subgenomic RNA.

• 대한수의학회지
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• 제38권1호
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• pp.167-172
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• 1998

한국 및 일본을 포함한 동아시아 지역에 벡터 매개성 바이러스에 의한 소 질병으로 인하여 경제적 손실이 몇년을 주기로 극심하게 나타나고 있다. 그러나 본 질병의 정확한 역학에 대하여는 아직까지 확실한 연구가 되어 있지 않은 상태이다. 본 연구에서는 벡터 매개성 질병에 대한 역학을 좀더 명확하게 밝히기 위하여, 일본 열도중 가장 멀리 떨어져 있으며, 아열대 지역에 속하는 오끼나와 섬에서 사육되고 있으면서 백신접종을 받지 않은 소(Japanese black cattle)를 대상으로 하여 1988년도부터 1992년도에 걸쳐 벡터 매개성 바이러스군에 대한 중화항체가를 측정하고 분석하였다. 소의 유행성 바이러스(bovine ephemeral virus)에 대한 항체 양성율은 연도 및 계절별로 크게 변화를 보였고, Ibaraki virus에 대한 항체양성율은 그 어느 다른 계절보다도 5월에 높은 항체가를 보였으며, Akabane virus에 대한 항체 양성율은 이바라키 바이러스에 대한 항체 양성율과 유사한 수준으로 나타났다. 한편 Chuzan virus에 대한 항체양성율은 계절적인 변화가 심하지 않은 것으로 나타났다.

• 한국가축번식학회지
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• 제19권2호
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• pp.89-93
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• 1995

In this study was demonstrate that retrovirus-mediated gene transfer is one of the promising alternatives to the conventional pronuclear DNA microinjection approach, especially in transferring the exogenous genes into the boving embryos. By co-culturing of zona of zona-free one-cell stage embryos with the retrovirus-producing cells for 24 hours followed by 6 days of culture in virus-free medium, we could get morulae and blastocysts expressing the E. coli LacZ genes which were transferred by our retrovirus vector. The results obtained in this study are summarized as follows : 1. Addition of 5$\mu\textrm{g}$/ml of polybrene in the embryo and virus-producing cell co-culture medium did not affect development of zona-free one-cell embryo. 2. Compared with the intact embryos removal of zona at one-cell stage before co-culturing with the virus-producing cells for one day caused only slight decrease of embryo develpment. 3. Co-culture of 625 zona-free one-cell stage embryos with the virus-producing cells resulted in 65(10.4%) morulae or blastocysts, and 12.3%(8/65) of the morulae or blastocysts were E. coli LacZ positive.

• 한국연초학회지
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• 제19권2호
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• pp.117-123
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• 1997

Viral coat protein (CP) encoding cDNA with artificial start and stop codons was synthesized by reverse-transcriptase polymerase chain reaction (RT-PCR) from the Korean isolate of potato virus Y-vein nectrosis strain (pVY-VN). To make PVY CP cDNA to untranslatable form, three stop codons were inserted near the start codon by "megaprimer-PCR" method. The untranslatable CP cDNA was subcloned to plant expression vector and transferred to N. tabacum cv. NC82 by Agrobacterium-mediated transformation. Highly resistant plants to PVY infection were screened, based on symptom development after mechanical virus inoculation. By genomic PCR and Southern blot analysis, one or more copies of the untranslatable CP gene were found in all transformants. From northern blot analysis, highly resistant transgenic lines had very low level of CP transcript but susceptible lines had high level, suggesting resistance to PVY infection should be related to RNA-mediated mechanism.mechanism.