Cell-to-cell movement of potexviruses: evidence for a ribonucleoprotein complex involving the coat protein and first triple gene block protein

Mol Plant Microbe Interact. 2000 Sep;13(9):962-74. doi: 10.1094/MPMI.2000.13.9.962.

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.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Biolistics
  • Capsid / genetics*
  • Mutation
  • Plants, Genetically Modified / cytology
  • Plants, Genetically Modified / virology*
  • Potexvirus / physiology*
  • Ribonucleoproteins / physiology*

Substances

  • Ribonucleoproteins