• Proceedings of the Korean Society of Plant Biotechnology Conference
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• 2005.11a
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• pp.351-355
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• 2005

In the storage roots of sweetpotato (Ipomoea batatas (L.) Lam. cv. Kokei 14), 10 to 20% of starch is essentially unbranched linear amylose and the other major component is branched amylopectin. Amylose is produced by the enzyme GBSSI (granule bound starch synthase I), whereas amylopectin is produced by a concerted action of soluble starch synthase and starch branching enzymes (SBEI and SBEII). We constructed double-stranded RNA (dsRNA) interference vectors of GBSSI and IbSBEII and introduced them into sweetpotato genome via Agrobacterium-mediated gene transformation. The endogenous GBSSI expression was inhibited by dsRNA of GBSSI in 73 % of transgenic plants giving rise to the storage tubers containing amylopectin but not amylose. On the other hand, all sweetpotato plants transformed with dsRNA of IbSBEII contained a larger amount of amylose than the non-transgenic control (up to 25% compared to 10% in the controls). The RNA interference (RNAi) is effectively inhibited the gene expression in thestarch metabolic pathway and modified the characteristics of starch in sweetpotato.

• The Plant Pathology Journal
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• v.20 no.2
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• pp.155-157
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• 2004

We isolated Rice dwarf virus (RDV) from infected plants in rice fields (Korea, Japan, China, the Philippines and Nepal) and analyzed their genomic dsRNAs by polyacrylamide gel eletrophoresis. The genomic dsRNAs of the isolates showed distinct electrophoretic mobility profiles. The S12 coding to nonstructural protein of Korean isolate (RDV-Kr) was further analyzed by sequencing. The S12 of RDV-Kr was 1,066bp long and coded for a protein composed of 312 amino acids including three open reading frames of P12, P120Pa and P120Pb. The sequence identities were 96% and 98.6% with Japanese isolates (H, AN), 94.7% with Nepalese isolate (NEL), 94% with Chinese isolate (CK) and the Philippines isolate (P).

• Journal of Microbiology and Biotechnology
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• v.31 no.4
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• pp.529-539
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• 2021

The beet armyworm, Spodoptera exigua, is a serious insect pest infesting various vegetable crops. Two infectious insect viruses, baculovirus and iflavirus, are known to induce epizootics in S. exigua populations. Indeed, some laboratory colonies have appeared to be covertly infected by these viruses. Diagnostic PCR tests detected two different viruses: Spodoptera exigua multiple nucleopolyhedrosis virus (SeMNPV) and iflaviruses (SeIfV1 and SeIfV2). Viral extract from dead larvae of S. exigua could infect Sf9 cells and produce occlusion bodies (OBs). Feeding OBs to asymptomatic larvae of S. exigua caused significant viral disease. Interestingly, both SeIfV1 and SeIfV2 increased their titers at late larval stages. Sterilization of laid eggs with 1% sodium hypochloride significantly reduced SeMNPV titers and increased larval survival rate. Double-stranded RNA (dsRNA) specific to SeIfV1 or SeIfV2 significantly reduced viral titers and increased larval survival rate. To continuously feed dsRNA, a recombinant Escherichia coli HT115 expressing SeIfV1-dsRNA was constructed with an L4440 expression vector. Adding this recombinant E. coli to the artificial diet significantly reduced the SeIfV1 titer and increased larval survival. These results indicate that laboratory colony collapse of S. exigua is induced by multiple viral infections. In addition, either suppression of SeMNPV or SeIfV infection significantly increased larval survival, suggesting a cooperative pathogenicity between baculovirus and iflavirus against S. exigua.

• Journal of Mushroom
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• v.8 no.2
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• pp.41-50
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• 2010

Mycoviruses have been found in many fungal species including mushrooms. Double-stranded (ds) RNA genomes were common type in mycoviruses, but single-stranded (ss) RNA mycoviruses were also reported in some fungal species. Sequencing analysis using cDNA cloning experiments revealed that mycoviruses can be classified into several different virus families such as Totiviridae, Hypoviridae, Partitiviridae and Barnaviridae etc. Because the nucleotide sequence data that are available in these days are very limited in a number of mycoviruses, the existence of more diverse viral groups in fungi are currently expected. In this review, we selected four different fungal groups, which were considered as the model systems for mycovirus related studies in both plant pathogenic fungi and edible mushroom species, and discussed about their molecular characteristics of diverse mycoviruses. The plant pathogenic fungi introduced here were Cryphonectria parasitica and Helminthosporium victoriae and the edible mushroom species were Agaricus bisporus and Pleurotus ostreatus.

• KSBB Journal
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• v.26 no.2
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• pp.131-138
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• 2011

Some computational approaches are needed for clarifying RNAi sequences, because it takes much time and endeavor that almost of RNAi sequences are verified by experimental data. Incorrectness of RNAi mechanism and other unaware factors in organism system are frequently faced with questions regarding potential use of RNAi as therapeutic applications. Our massive parallelized pair alignment scoring between dsRNA in Genebank and expressed sequence tags (ESTs) in Caenorhabditis elegans Genome Sequencing Projects revealed that this provides a useful tool for the prediction of RNAi induced cosuppression details for practical use. This pair alignment scoring method using high performance computing exhibited some possibility that numerous unwanted gene silencing and cosuppression exist even at high matching scores each other. The classifying the relative higher matching score of them based on GO (Gene Ontology) system could present mapping dsRNA of C. elegans and functional roles in an applied system. Our prediction also exhibited that more than 78% of the predicted co-suppressible genes are located in the ribosomal spot of C. elegans.

• Journal of Microbiology and Biotechnology
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• v.4 no.4
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• pp.264-269
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• 1994

To determine the nucleotide sequence of the ds RNA segment B containing the RNA dependent RNA polymerase (RdRp) gene of the DRT strain of infectious pancreatic necrosis virus (lPNV), the cDNA of the ds RNA segment B of the DRT strain of IPNV was synthesized using the reverse transcriptase (RT)-polymerase chain reaction (PCR) and its cDNA nucleotide sequence was determined. The DRT segment B was 2, 783 bp long and contained only a single long open reading frame (ORF) of 2, 535 bp in length. This ORF nucleotides encoded the VPl protein, the putative RdRp of IPNV. The VPl protein comsisted of 845 amino acids. The molecular weight of the RdRp, as deduced from the nucleotide sequence, is 94, 426. The nucleotide sequence of the ORF of the DRT showed 89.7% homology to the Jasper strain, but 80.8% to the Sp strain. The amino acid sequence of the ORF of the DRT sho.wed 97.6% homology to the Jasper strain, but 88.7% to the Sp strain. The conserved GTP-binding motif was detected in VPl protein.

• Journal of Life Science
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• v.19 no.3
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• pp.317-321
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• 2009

Down syndrome (DS) results from overexpressed genes on an extra copy of human chromosome 21. Among various phenotypes seen in DS patients, mental retardation, such as learning and memory deficits, is a major factor that prevents DS individuals from leading fully independent lives. The Dyrk1A gene that plays a critical role in neurodevelopment has been isolated from chromosome 21, and transgenic mice with over-expression of Dyrk1A show severe hippocampal dependent learning and memory defects. In the present study, as an initial step to test the treatment of Dyrk1A dependent mental retardation phenotypes in model animals, we isolated human Dyrk1A specific lentiviral short hairpin RNA (shRNA) that inhibits the exogenous human Dyrk1A expression, but not the endogenous mouse expression in transgenic mice with human Dyrk1A overexpression. This limited and specific repression of exogenous human Dyrk1A will prove to be valuable information, if Dyrk1A dependent learning and memory defects in DS patients could be treated or at least ameliorated in vivo.

• Bulletin of the Korean Chemical Society
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• v.32 no.11
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• pp.3893-3898
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• 2011

Cellular uptake of double-stranded DNA (dsDNA) triggers strong innate immune responses via activation of NF-${\kappa}B$ transcription factor. However, the detailed mechanism of dsDNA-mediated innate immune response remains yet to be elucidated. Here, we show that the expression of tazarotene-induced gene 3 (TIG3) is dramatically induced by dsDNA stimulation, and the siRNA-mediated down-regulation of TIG3 mRNA results in significant suppression of dsDNA-triggered cytokine expression. Because TIG3 has been previously shown to physically interact with transglutaminase (TG) 1 to activate TG activity, and TG2 has been shown to induce NF-${\kappa}B$ activity by inducing $I{\kappa}B{\alpha}$ polymerization, we tested whether TG also plays a role in dsDNA-mediated innate immune response. Pre-treatment of TG inhibitors dramatically reduces dsDNA-triggered cytokine induction. We also show that, in HeLa cells, TG2 is the major TG, and TIG3 physically interacts with TG2. Combined together, our results suggest a novel mechanism of dsDNA-triggered innate immune response which is critically dependent on TIG3 and TG2.

• Research in Plant Disease
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• v.14 no.3
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• pp.229-232
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• 2008

An isolate of Cucumber mosaic virus (CMV), designated as Cas-CMV, was isolated from Chinese aster (Callistephus chinensis) showing severe mosaic symptom, and its properties was compared to the well-characterized Fny-CMV (subgroup IA) and As-CMV (subgroup IB) by host reaction in several indicator plants, dsRNA analysis, RT-PCR analysis, and restriction enzyme profile of the PCR products. Cas-CMV differed markedly in their host reaction to Fny-CMV or As-CMV in Cucurbita pepo cv. Black beauty. In the zucchini squash, all strains induced chlorotic spot on inoculated leaves and mosaic symptoms on upper leaves. However, symptoms induced by Cas-CMV were developed lethal necrosis on the young plants 15 to 20 days after inoculation. In experiments of dsRNA analysis and RT-PCR analysis, properties of Cas-CMV was come within subgroup I CMV. Moreover, restriction enzyme analysis using HindIII of the RT-PCR products showed that Cas-CMV belong to a member of CMV subgroup IA.

• Research in Plant Disease
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• v.14 no.1
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• pp.71-75
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• 2008

An isolate of Peanut stunt virus (PSV), named as Tr-PSV, was isolated from white clover (Trifolium repens L) showing mosaic symptom. Tr-PSV systemically infected all plants tested in the Nicotiana spp. and induced local lesions on inoculated leaves of Chenopodium amaranticolor. However, Tr-PSV induced typical mosaic symptoms as ER-PSV on Vigna unguiculata 5 to 6 days after inoculation, while Fny-CMV used as a control virus of Cucumovirus produced local lesions on inoculated leaves. In dsRNA analysis, Tr-PSV consisted of four dsRNAs, but satellite RNA was not detected. The cDNA of coat protein gene of Tr-PSV was amplified by RT-PCR using a Cucumovirus-specific single pair primers that designed to amplify a DNA fragment of approximately 950 bp. By restriction mapping analysis using RFLP of the RT-PCR products and by serological properties of gel diffusion test, Tr-PSV belongs to a typical member of PSV subgroup I. This is the first report on the occurrence of PSV in white clover in Korea.