title: Over-expression of putative transcriptional coactivator KELP interferes with Tomato mosaic virus cell-to-cell movement.
abstract: Tomato mosaic virus (ToMV) encodes a movement protein (MP) that is necessary for virus cell-to-cell movement. We have demonstrated previously that KELP, a putative transcriptional coactivator of Arabidopsis thaliana, and its orthologue from Brassica campestris can bind to ToMV MP in vitro. In this study, we examined the effects of the transient over-expression of KELP on ToMV infection and the intracellular localization of MP in Nicotiana benthamiana, an experimental host of the virus. In co-bombardment experiments, the over-expression of KELP inhibited virus cell-to-cell movement. The N-terminal half of KELP (KELPdC), which had been shown to bind to MP, was sufficient for inhibition. Furthermore, the over-expression of KELP and KELPdC, both of which were co-localized with ToMV MP, led to a reduction in the plasmodesmal association of MP. In the absence of MP expression, KELP was localized in the nucleus and the cytoplasm by the localization signal in its N-terminal half. It was also shown that ToMV amplified normally in protoplasts prepared from leaf tissue that expressed KELP transiently. These results indicate that over-expressed KELP interacts with MP in vivo and exerts an inhibitory effect on MP function for virus cell-to-cell movement, but not on virus amplification in individual cells.
authors.affiliation: Gene Research Centre, Tokyo University of Agriculture and Technology, Fuchu, Tokyo 183-8509, Japan.
authors.forename: Nobumitsu
authors.initials: N
authors.lastname: Sasaki
authors.forename: Takuya
authors.initials: T
authors.lastname: Ogata
authors.forename: Masakazu
authors.initials: M
authors.lastname: Deguchi
authors.forename: Shoko
authors.initials: S
authors.lastname: Nagai
authors.forename: Atsushi
authors.initials: A
authors.lastname: Tamai
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Meshi
authors.forename: Shigeki
authors.initials: S
authors.lastname: Kawakami
authors.forename: Yuichiro
authors.initials: Y
authors.lastname: Watanabe
authors.forename: Yasuhiko
authors.initials: Y
authors.lastname: Matsushita
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Nyunoya
mesh_terms: D029681:Arabidopsis Proteins / Q000378:metabolism*; D036022:Capsid Proteins / Q000378:metabolism; D042541:Intracellular Space / Q000378:metabolism / Q000821:virology; D053830:Plant Viral Movement Proteins / Q000378:metabolism; D010942:Plant Viruses / Q000502:physiology*; D021381:Protein Transport; D011523:Protoplasts / Q000821:virology; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D013347:Subcellular Fractions / Q000378:metabolism; D014026:Nicotiana / Q000166:cytology* / Q000821:virology*; D015534:Trans-Activators / Q000378:metabolism*; D014779:Virus Replication
chemical_list: D029681:Arabidopsis Proteins; D036022:Capsid Proteins; C113673:KELP protein, Arabidopsis; D053830:Plant Viral Movement Proteins; D011993:Recombinant Fusion Proteins; D015534:Trans-Activators