Distinct functional domains in the cowpea mosaic virus movement protein

Abstract

Cell-to-cell movement of cowpea mosaic virus particles in plants takes place with the help of tubules that penetrate presumably modified plasmodesmata. These tubules, which are built up by the virus-encoded 48-kDa movement protein (MP), are also formed on single protoplast cells. To determine whether the MP contains different functional domains, the effect of mutations in its coding region was studied. Mutations between amino acids 1 and 313 led to complete abolishment of the tubule-forming capacity, while a deletion in the C-terminal region resulted in tubules that could not take up virus particles. From these observations, it is concluded that the MP contains at least two distinct domains, one that is involved in tubule formation and that spans amino acids 1 and 313 and a second that is probably involved in the incorporation of virus particles in the tubule and that is located in the C terminus between amino acids 314 and 331.

Interaction of Sesbania mosaic virus movement protein with the coat protein – implications for viral spread

“…These observations suggest that there is a major interacting domain within the N-terminal 49 amino acids of the SeMV MP. This is in contrast to observations on CPMV MP, in which the C-terminal domain was shown to be involved in NV recognition and binding [41,42].…”

Identification of Inhibitory Mutants of Cauliflower mosaic virus Movement Protein Function after Expression in Insect Cells

“…We proposed previously that the N and C termini of the CaMV MP were not embedded in its three-dimensional structure and that the C terminus could project into the lumen of the tubule. Experiments with CPMV (14) supported the view that this region may be involved in the interaction with virus particles. The SDMs with deletions in the N terminus did not prevent tubule formation or virus movement, although deletion of the encompassing region inhibited both functions, indicating that although this region is surface located, it is integral to the structure required for tubule formation.…”

Identification of distinct steps during tubule formation by the movement protein of Cowpea mosaic virus

“…The resulting PCR products were digested with BglII and BamHI and cloned into BglII/BamHI-digested pTMPfGFP. The BamHI site is located in the 39-end of the MP coding region and therefore all MP C-terminal deletion mutants still contain the last 11 amino acids of the C terminus of MP, in contrast to the previously described C-terminal deletion mutants (Bertens et al, 2003;Lekkerkerker et al, 1996). The presence of these amino acids should not influence the localization of the mutants, since they are not required for targeting MP to the cell periphery or for tubule formation (Lekkerkerker et al, 1996).…”

“…Previous studies have indicated the presence of several functional domains in the CPMV MP (Bertens et al, 2000(Bertens et al, , 2003Carvalho et al, 2003;Lekkerkerker et al, 1996). The C terminus of the MP was shown to be involved in the interaction with virus particles in the tubule and the remaining part of the protein was found to be required for tubule formation.…”