Identification of distinct steps during tubule formation by the movement protein of Cowpea mosaic virus.
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.
Pouwels
Jeroen
J
Laboratory of Molecular Biology, Wageningen University, Dreijenlaan 3, 6703 HA Wageningen, The Netherlands.
Kornet
Noortje
N
Laboratory of Molecular Biology, Wageningen University, Dreijenlaan 3, 6703 HA Wageningen, The Netherlands.
van Bers
Nikkie
N
Laboratory of Molecular Biology, Wageningen University, Dreijenlaan 3, 6703 HA Wageningen, The Netherlands.
Guighelaar
Teun
T
Laboratory of Molecular Biology, Wageningen University, Dreijenlaan 3, 6703 HA Wageningen, The Netherlands.
van Lent
Jan
J
Laboratory of Virology, Wageningen University, Binnenhaven 11, 6709 PD Wageningen, The Netherlands.
Bisseling
Ton
T
Laboratory of Molecular Biology, Wageningen University, Dreijenlaan 3, 6703 HA Wageningen, The Netherlands.
Wellink
Joan
J
Laboratory of Molecular Biology, Wageningen University, Dreijenlaan 3, 6703 HA Wageningen, The Netherlands.
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*
D053830:Plant Viral Movement Proteins; D014764:Viral Proteins