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Subcellular localization and <i>in vivo</i> identification of the putative movement protein of olive latent virus 2
Auteur(s)
Grieco, Francesco
Castellano, Maria Antonietta
Di Sansebastiano, Gian Pietro
Maggipinto, Giovanna
Martelli, Giovanni P.
Date de parution
1999
In
Journal of General Virology, Society for General Microbiology, 1999/80//1103-1109
Résumé
The gene encoding the 36.5 kDa ('36K') nonstructural protein located on RNA3 of olive latent virus 2 (OLV-2) was cloned, expressed with the <i>Escherichia coli</i> pGEX-2T system and the purified protein used to raise a polyclonal antiserum. Immunoblot analysis of OLV-2-infected <i>Nicotiana benthamiana</i> plants showed that the 36K protein accumulated in the early stages of infection and was associated with a subcellular fraction enriched in cytoplasmic membranes. In infected cells there were tubular structures, some containing virus-like particles, scattered in the cytoplasm or protruding from or penetrating the cell wall at the plasmodesmata. Immunogold labelling localized the 36K protein in the plasmodesmata of OLV-2-infected cells and showed it to be associated with virus-containing tubules. Leaf trichome cells of <i>N. tabacum</i> plants, transformed with a 36K--green fluorescent protein (GFP) fusion construct, revealed localized fluorescence in the cell walls, possibly due to association of the fusion protein with plasmodesmata. When the same 36K--GFP fusion protein was expressed in <i>N. tabacum</i> protoplasts, long tubular fluorescent structures protruded from the protoplast surface, suggesting that the 36K protein is responsible for tubule induction. The conclusion is drawn that this protein is likely to be the OLV-2 movement protein, mediating cell-to-cell virus movement, and that movement is by a tubule-guided mechanism.
Identifiants
Type de publication
journal article
