title: Identification of distinct steps during tubule formation by the movement protein of Cowpea mosaic virus.
abstract: The movement protein (MP) of Cowpea mosaic virus (CPMV) forms tubules through plasmodesmata in infected plants thus enabling virus particles to move from cell to cell. Localization studies of mutant MPs fused to GFP in protoplasts and plants identified several functional domains within the MP that are involved in distinct steps during tubule formation. Coinoculation experiments and the observation that one of the C-terminal deletion mutants accumulated uniformly in the plasma membrane suggest that dimeric or multimeric MP is first targeted to the plasma membrane. At the plasma membrane the MP quickly accumulates in peripheral punctuate spots, from which tubule formation is initiated. One of the mutant MPs formed tubules containing virus particles on protoplasts, but could not support cell-to-cell movement in plants. The observations that this mutant MP accumulated to a higher level in the cell than wt MP and did not accumulate in the cell wall opposite infected cells suggest that breakdown or disassembly of tubules in neighbouring, uninfected cells is required for cell-to-cell movement.
authors.affiliation: Laboratory of Molecular Biology, Wageningen University, Dreijenlaan 3, 6703 HA Wageningen, The Netherlands.
authors.forename: Jeroen
authors.initials: J
authors.lastname: Pouwels
authors.affiliation: Laboratory of Molecular Biology, Wageningen University, Dreijenlaan 3, 6703 HA Wageningen, The Netherlands.
authors.forename: Noortje
authors.initials: N
authors.lastname: Kornet
authors.affiliation: Laboratory of Molecular Biology, Wageningen University, Dreijenlaan 3, 6703 HA Wageningen, The Netherlands.
authors.forename: Nikkie
authors.initials: N
authors.lastname: van Bers
authors.affiliation: Laboratory of Molecular Biology, Wageningen University, Dreijenlaan 3, 6703 HA Wageningen, The Netherlands.
authors.forename: Teun
authors.initials: T
authors.lastname: Guighelaar
authors.affiliation: Laboratory of Virology, Wageningen University, Binnenhaven 11, 6709 PD Wageningen, The Netherlands.
authors.forename: Jan
authors.initials: J
authors.lastname: van Lent
authors.affiliation: Laboratory of Molecular Biology, Wageningen University, Dreijenlaan 3, 6703 HA Wageningen, The Netherlands.
authors.forename: Ton
authors.initials: T
authors.lastname: Bisseling
authors.affiliation: Laboratory of Molecular Biology, Wageningen University, Dreijenlaan 3, 6703 HA Wageningen, The Netherlands.
authors.forename: Joan
authors.initials: J
authors.lastname: Wellink
mesh_terms: D001692:Biological Transport; D002462:Cell Membrane / Q000378:metabolism; D017798:Comovirus / Q000378:metabolism* / Q000472:pathogenicity; D019281:Dimerization; D018613:Microscopy, Confocal; D018532:Pisum sativum / Q000821:virology*; D010935:Plant Diseases / Q000821:virology; D018515:Plant Leaves / Q000378:metabolism; D053830:Plant Viral Movement Proteins; D017354:Point Mutation; D017434:Protein Structure, Tertiary; D011523:Protoplasts / Q000378:metabolism; D014764:Viral Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: D053830:Plant Viral Movement Proteins; D014764:Viral Proteins