[Show abstract][Hide abstract] ABSTRACT: The eukaryotic translation initiation factor 4E (eIF4E) (the cap-binding protein) is involved in natural resistance against
several potyviruses in plants. In lettuce, the recessive resistance genes mo11 and mo12 against Lettuce mosaic virus (LMV) are alleles coding for forms of eIF4E unable, or less effective, to support virus accumulation. A recombinant LMV expressing
the eIF4E of a susceptible lettuce variety from its genome was able to produce symptoms in mo11 or mo12 varieties. In order to identify the eIF4E amino acid residues necessary for viral infection, we constructed recombinant LMV
expressing eIF4E with point mutations affecting various amino acids and compared the abilities of these eIF4E mutants to complement
LMV infection in resistant plants. Three types of mutations were produced in order to affect different biochemical functions
of eIF4E: cap binding, eIF4G binding, and putative interaction with other virus or host proteins. Several mutations severely
reduced the ability of eIF4E to complement LMV accumulation in a resistant host and impeded essential eIF4E functions in yeast.
However, the ability of eIF4E to bind a cap analogue or to fully interact with eIF4G appeared unlinked to LMV infection. In
addition to providing a functional mutational map of a plant eIF4E, this suggests that the role of eIF4E in the LMV cycle
might be distinct from its physiological function in cellular mRNA translation.
Full-text · Article · Sep 2008 · Journal of Virology
[Show abstract][Hide abstract] ABSTRACT: Using recombinant proteins produced in bacteria or in infected plants, interactions between the VPg and HcPro of Lettuce mosaic potyvirus (LMV) and between LMV VPg and the lettuce translation initiation factor 4E, the cap-binding protein (eIF4E), were demonstrated in vitro. Interaction with eIF4E and HcPro both involved the same VPg central domain. The structure of this domain in the VPg context was predicted to include an amphiphilic alpha-helix, with the amino acids related to biological functions in various potyviruses exposed at the hydrophilic side.
Full-text · Article · Apr 2007 · Journal of General Virology
[Show abstract][Hide abstract] ABSTRACT: Monoclonal antibodies were raised against helper component-proteinase (HcPro) purified from plants infected with the potyvirus Lettuce mosaic virus (LMV). These antibodies were used in a two-site triple antibody sandwich ELISA assay together with polyclonal antibodies directed against purified virions. An interaction between HcPro and the viral coat protein (CP) was demonstrated in extracts of LMV-infected leaves, as well as for two other potyviruses, Plum pox virus and Potato virus Y. The CP-HcPro interaction was not abolished in LMV derivatives with an HcPro GFP N-terminal fusion, or with a deletion from the CP of the amino acids involved in aphid transmission. Electron microscopy indicated that HcPro probably does not interact with the CP in the form of assembled virions or virus-like particles. Together, these results suggest that the interaction detected between CP and HcPro might be involved in a process of the potyvirus cycle different from aphid transmission.
Full-text · Article · Aug 2002 · Journal of General Virology