| Project/Area Number |
18580045
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Plant pathology
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| Research Institution | St.Marianna University School of Medicine |
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Principal Investigator |
MIYOSHI Hiroshi St.Marianna University School of Medicine, Dept. Microbiol, lecturer (80322519)
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| Co-Investigator(Kenkyū-buntansha) |
NATSUAKI Tomohide Utsunomiya Univ., Dept. Plant Pathol., Professor (10134264)
TOMOO Koji Osaka Univ. of Pharm. Sc., Dept. Phys. Chem., Associate Professor (70257898)
NISHIKAWA Hiroyuki St. Marianna Univ. Sch. Of Med., Inst. Adv. Med. Sci., Research Associate (90387077)
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| Project Period (FY) |
2006 – 2007
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| Project Status |
Completed (Fiscal Year 2007)
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| Budget Amount *help |
¥3,890,000 (Direct Cost: ¥3,500,000、Indirect Cost: ¥390,000)
Fiscal Year 2007: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000)
Fiscal Year 2006: ¥2,200,000 (Direct Cost: ¥2,200,000)
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| Keywords | Arabidopsis thaliana / Potyvirus / translation initiation factor / genome-linked protein / ゲノム結合蛋白質 / ボティウイルス |
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| Research Abstract |
I. Interaction of VPg of TuMV with Wheat Germ Translation Initiation Factors eIF(iso)4E and eIFiso4F.
The interaction between VPg of TuMV and wheat germ eukaryotic translation initiation factors eIF(iso)4E and eIF(iso)4F were measured and compared. The fluorescence quenching data showed the presence of one binding site on eIF(iso)4E for VPg. A Line weaver-Burk plot indicates mixed-type competitive ligand binding between VPg and anthraniloyl-m^7GTP for eIF(iso)4E. Fluorescence stopped-flow studies of eIF(iso)4E and eIF(iso)4F with VPg show rapid binding, suggesting kinetic competition between VPg and m^7G cap. The VPg protein binds much faster than cap analogs. Enhancement of eIF(iso)4F-VPg binding with the addition of a structured RNA derived from TEV suggests that translation initiation involving VPg occurs at internal ribosomal entry sites. Furthermore, the formation of a protein-RNA complex containing VPg suggests the possibility of direct participation of VPg in the translation of t
… More
he viral genome.
II. Potyvirus VPg directly affects wheat germ in vitro translation.
We show that addition of VPg to wheat germ extract leads to enhancement of uncapped viral mRNA translation and inhibition of capped viral mRNA translation. This provides a significant competitive advantage to the uncapped viral mRNA. We demonstrate that eIF(iso)4F can kinetically compete with eIF4F for VPg binding. The quantitative data presented here suggest a model where eIF4F-VPg interaction enhances cap-independent translation by increasing the affinity of eIF4F for TEV RNA. This is the first evidence of direct participation of VPg in translation initiation.
III. TuMV VPg interacts with Arabidopsis thaliana eIF(iso)4E and inhibits in vitro translation.
The interaction between TuMV VPg and Arabidopsis thaliana eIF(iso)4E was investigated to address the influence of potyviral VPg on host cellular translational initiation. In vitro translation analysis showed that the addition of VPg significantly inhibited translation of capped RNA in eIF(iso)4E-reconstituted wheat germ extract. This result indicates that VPg inhibits cap-dependent translational initiation via binding to eIF(iso)4E. Our present results may indicate that excess VPg produced at the encapsidation stage shuts off cap-dependent translational initiation in host cells by inhibiting complex formation between eIF(iso)4E and cellular mRNAs. Less
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