title: Cell-to-cell movement of potexviruses: evidence for a ribonucleoprotein complex involving the coat protein and first triple gene block protein.
abstract: The triple gene block proteins (TGBp1-3) and coat protein (CP) of potexviruses are required for cell-to-cell movement. Separate models have been proposed for intercellular movement of two of these viruses, transport of intact virions, or a ribonucleoprotein complex (RNP) comprising genomic RNA, TGBp1, and the CP. At issue therefore, is the form(s) in which RNA transport occurs and the roles of TGBp1-3 and the CP in movement. Evidence is presented that, based on microprojectile bombardment studies, TGBp1 and the CP, but not TGBp2 or TGBp3, are co-translocated between cells with viral RNA. In addition, cell-to-cell movement and encapsidation functions of the CP were shown to be separable, and the rate-limiting factor of potexvirus movement was shown not to be virion accumulation, but rather, the presence of TGBp1-3 and the CP in the infected cell. These findings are consistent with a common mode of transport for potexviruses, involving a non-virion RNP, and show that TGBp1 is the movement protein, whereas TGBp2 and TGBp3 are either involved in intracellular transport or interact with the cellular machinery/docking sites at the plasmodesmata.
authors.affiliation: Horticulture and Food Research Institute of New Zealand, Plant Health and Development Group, Auckland. tlough@hort.cri.nz
authors.forename: T J
authors.initials: TJ
authors.lastname: Lough
authors.forename: N E
authors.initials: NE
authors.lastname: Netzler
authors.forename: S J
authors.initials: SJ
authors.lastname: Emerson
authors.forename: P
authors.initials: P
authors.lastname: Sutherland
authors.forename: F
authors.initials: F
authors.lastname: Carr
authors.forename: D L
authors.initials: DL
authors.lastname: Beck
authors.forename: W J
authors.initials: WJ
authors.lastname: Lucas
authors.forename: R L
authors.initials: RL
authors.lastname: Forster
mesh_terms: D019470:Biolistics; D002213:Capsid / Q000235:genetics*; D009154:Mutation; D030821:Plants, Genetically Modified / Q000166:cytology / Q000821:virology*; D017863:Potexvirus / Q000502:physiology*; D012261:Ribonucleoproteins / Q000502:physiology*
chemical_list: D012261:Ribonucleoproteins