| Project/Area Number |
10480188
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| Research Category |
Grant-in-Aid for Scientific Research (B).
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Molecular biology
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| Research Institution | HOKKAIDO UNIVERSITY |
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Principal Investigator |
ISHIKAWA Masayuki Hokkaido University Graduate School of Agriculture, Associate Professor, 大学院・農学研究科, 助教授 (70192482)
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| Co-Investigator(Kenkyū-buntansha) |
NAITO Satoshi Hokkaido University Graduate School of Agriculture, Professor, 大学院・農学研究科, 教授 (20164105)
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| Project Period (FY) |
1998 – 2000
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| Project Status |
Completed (Fiscal Year 2000)
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| Budget Amount *help |
¥11,000,000 (Direct Cost: ¥11,000,000)
Fiscal Year 2000: ¥3,000,000 (Direct Cost: ¥3,000,000)
Fiscal Year 1999: ¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 1998: ¥4,400,000 (Direct Cost: ¥4,400,000)
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| Keywords | Arabidopsis / tobacco mosaic virus / RNA replication, host factors / host factors |
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| Research Abstract |
In this research, we identified and analyzed Arabidopsis TOM1 and TOM2 genes which are necessary for the efficient multiplication of tobacco mosaic virus (TMV) within a single cell. By positional cloning, we found TOM1 encodes a putative seven-pass transmembrane protein of 291 amino acids. We also revealed that two independent genes named TOM2A and TOM2B are involved in the expression of the phenotype of reduced multiplication of TMV in the tom2 mutant. TOM2A encodes a putative 4-pass transmembrane protein of 280 amino acids, whereas TOM2B encodes a 122 amino-acid protein. In order to know how these host proteins support TMV multiplication, we examined the interaction between these host proteins and TMV-encoded proteins by the Sos recruitment system in yeast. Through these analyses, we found that TOM1 protein could interact with the helicase domain of TMV-encoded 130 k protein. The replication complexes of higher eukaryotic positive-strand RNA viruses including TMV are known to be associated with intracellular membranes. However, the mechanisms by which TMV-encoded replication proteins are localized on membranes had not been known. From our results, it was suggested that TOM1 may be present in the TMV replication complex and function to connect the complex with membranes. All three tom1 mutant alleles obtained so far are likely to have lost their function completely.
Nevertheless, TMV can still multiply to low levels in these tom1 mutants. In this study, we found that this residual activity to support TMV multiplication in tom1 mutants is from TOM3, a TOM1 homologue present in the Arabidopsis genome, and therefore, the function of TOM1/TOM3 is necessary for TMV multiplication.
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