Open AccessCell-to-Cell Movement of Potexviruses: Evidence for a Ribonucleoprotein Complex Involving the Coat Protein and First Triple Gene Block Protein
Author(s) -
Tony J. Lough,
Natalie E. Netzler,
Sarah Emerson,
Paul Sutherland,
Fiona Carr,
David L. Beck,
William J. Lucas,
R. L. S. Forster
Publication year - 2000
Publication title -
molecular plant-microbe interactions
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.565
H-Index - 153
eISSN - 1943-7706
pISSN - 0894-0282
DOI - 10.1094/mpmi.2000.13.9.962
Subject(s) - movement protein , plasmodesma , biology , ribonucleoprotein , microbiology and biotechnology , rna , gene , heterogeneous nuclear ribonucleoprotein , genetics , coat protein , cytoplasm
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 inter-cellular 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 potex-viruses, 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.