The Cognate Coat Protein Is Required for Cell-to-Cell Movement of a Chimeric Brome Mosaic Virus Mediated by the Cucumber Mosaic Virus Movement Protein
Authors: Nagano H.1; Mise K.1; Okuno T.2; Furusawa I.1
Source: Virology, Volume 265, Number 2, December 1999 , pp. 226-234(9)
Publisher: Academic Press
Abstract:
Cucumber mosaic cucumovirus (CMV) and brome mosaic bromovirus (BMV) have many similarities, including the three-dimensional structure of virions, genome organizations, and requirement of the coat protein (CP) for cell-to-cell movement. We have shown that a chimeric BMV with the CMV 3a movement protein (MP) gene instead of its own cannot move from cell to cell in Chenopodium quinoa, a common permissive host for both BMV and CMV. Another chimeric BMV was constructed by replacing both MP and CP genes of BMV with those of CMV (MP/CP-chimera) and tested for its infectivity in C. quinoa, to determine whether the CMV CP has some functions required for the CMV MP-mediated cell-to-cell movement and to exhibit functional difference between CPs of BMV and CMV. Cell-to-cell movement of the MP/CP-chimera occurred, and small local lesions were induced on the inoculated leaves. A frameshift mutation introduced in the CMV CP gene of the MP/CP-chimera resulted in a lack of cell-to-cell movement of the chimeric virus. These results indicate that the viral movement mediated by the CMV MP requires its cognate CP. Deletion of the amino-terminal region in CMV CP, which is not obligatory for CMV movement, also abolished cell-to-cell movement of the MP/CP-chimera. This may suggest some differences in cell-to-cell movement of the MP/CP-chimera and CMV. On the other hand, the sole replacement of BMV CP gene with that of CMV abolished viral cell-to-cell movement, suggesting a possibility that the viral movement mediated by the BMV MP may also require its cognate CP. Functional compatibility between MP and CP in viral cell-to-cell movement is discussed. Copyright 1999 Academic Press.
Language: English
Document Type: Research article
Affiliations: 1: Graduate School of Agriculture, Kyoto University, Kyoto, 606-8502, Japan 2: Faculty of Agriculture, Kochi University, Nankoku, 783-8502, Japan

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