Role of the alfalfa mosaic virus movement protein and coat protein in virus transport.
The movement protein (MP) and coat protein (CP) encoded by Alfalfa mosaic virus (AMV) RNA 3 are both required for virus transport. RNA 3 vectors that expressed nonfused green fluorescent protein (GFP), MP:GPF fusions, or GFP:CP fusions were used to study the functioning of mutant MP and CP in protoplasts and plants. C-terminal deletions of up to 21 amino acids did not interfere with the function of the CP in cell-to-cell movement, although some of these mutations interfered with virion assembly. Deletion of the N-terminal 11 or C-terminal 45 amino acids did not interfere with the ability of MP to assemble into tubular structures on the protoplast surface. Additionally, N- or C-terminal deletions disrupted tubule formation. A GFP:CP fusion was targeted specifically into tubules consisting of a wild-type MP. All MP deletion mutants that showed cell-to-cell and systemic movement in plants were able to form tubular structures on the surface of protoplasts. Brome mosaic virus (BMV) MP did not support AMV transport. When the C-terminal 48 amino acids were replaced by the C-terminal 44 amino acids of the AMV MP, however, the BMV/AMV chimeric protein permitted wild-type levels of AMV transport. Apparently, the C terminus of the AMV MP, although dispensable for cell-to-cell movement, confers specificity to the transport process.
Sánchez-Navarro
J A
JA
Institute of Molecular Plant Sciences, Gorlaeus Laboratories, Leiden University, The Netherlands.
Bol
J F
JF
D017794:Alfalfa mosaic virus / Q000235:genetics / Q000472:pathogenicity / Q000502:physiology*; D001483:Base Sequence; D017795:Bromovirus / Q000235:genetics / Q000502:physiology; D002213:Capsid / Q000502:physiology*; D036022:Capsid Proteins; D004274:DNA, Recombinant / Q000235:genetics; D049452:Green Fluorescent Proteins; D008164:Luminescent Proteins / Q000235:genetics; D009068:Movement; D018515:Plant Leaves / Q000821:virology; D053830:Plant Viral Movement Proteins; D030821:Plants, Genetically Modified; D011523:Protoplasts / Q000821:virology; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000502:physiology; D017384:Sequence Deletion; D014026:Nicotiana / Q000235:genetics / Q000821:virology; D014764:Viral Proteins / Q000502:physiology*
D036022:Capsid Proteins; D004274:DNA, Recombinant; D008164:Luminescent Proteins; D053830:Plant Viral Movement Proteins; D011993:Recombinant Fusion Proteins; D014764:Viral Proteins; C095691:coat protein, Alfalfa mosaic virus; D049452:Green Fluorescent Proteins