Interaction of VPg-Pro of turnip mosaic virus with the translation initiation factor 4E and the poly(A)-binding protein in planta.
The viral protein linked to the genome (VPg) of Turnip mosaic virus (TuMV) interacts in vitro with the translation eukaryotic initiation factor (eIF) 4E. In the present study, we investigated the consequence of TuMV infection on eIF4E expression. Two isomers are present in plants, namely eIF4E and eIF(iso)4E. Expression of the latter was detected in both TuMV-infected and mock-inoculated Brassica perviridis plants, but expression of eIF4E was found only in infected plants. Membranes from TuMV-infected or mock-inoculated tissues were separated by sucrose gradient centrifugation and fractions were collected. Immunoblot analyses showed that 6K(2)-VPg-Pro/VPg-Pro polyproteins were associated with endoplasmic reticulum membranes and were the viral forms likely to interact with eIF(iso)4E and eIF4E. In planta interaction between 6K(2)-VPg-Pro/VPg-Pro and eIF(iso)4E/eIF4E was confirmed by co-purification by metal chelation chromatography. The poly(A)-binding protein (PABP) was also found to co-purify with VPg-Pro. Direct interaction between VPg-Pro and PABP was shown by an ELISA-based binding assay. These experiments suggest that a multi-protein complex may form around VPg-Pro of TuMV.
Léonard
Simon
S
Institut National de la Recherche Scientifique, Institut Armand-Frappier, 531 boulevard des Prairies, Laval, Québec, Canada H7V 1B7.
Viel
Catherine
C
Institut National de la Recherche Scientifique, Institut Armand-Frappier, 531 boulevard des Prairies, Laval, Québec, Canada H7V 1B7.
Beauchemin
Chantal
C
Institut National de la Recherche Scientifique, Institut Armand-Frappier, 531 boulevard des Prairies, Laval, Québec, Canada H7V 1B7.
Daigneault
Nicole
N
Institut National de la Recherche Scientifique, Institut Armand-Frappier, 531 boulevard des Prairies, Laval, Québec, Canada H7V 1B7.
Fortin
Marc G
MG
Department of Plant Science, McGill University, 21 111 Lakeshore, Ste-Anne-de-Bellevue, Québec, Canada H9X 3V9.
Laliberté
Jean-François
JF
Institut National de la Recherche Scientifique, Institut Armand-Frappier, 531 boulevard des Prairies, Laval, Québec, Canada H7V 1B7.
D001483:Base Sequence; D001937:Brassica / Q000235:genetics / Q000502:physiology / Q000821:virology*; D002462:Cell Membrane / Q000502:physiology / Q000821:virology; D018744:DNA, Plant / Q000235:genetics; D039561:Eukaryotic Initiation Factor-4E / Q000235:genetics / Q000502:physiology*; D046911:Macromolecular Substances; D010935:Plant Diseases / Q000235:genetics / Q000821:virology; D039102:Poly(A)-Binding Proteins / Q000235:genetics / Q000502:physiology*; D017800:Potyvirus / Q000235:genetics / Q000502:physiology*; D014176:Protein Biosynthesis; D020033:Protein Isoforms / Q000235:genetics / Q000502:physiology; D014758:Viral Core Proteins / Q000235:genetics / Q000502:physiology*
D018744:DNA, Plant; D039561:Eukaryotic Initiation Factor-4E; D046911:Macromolecular Substances; D039102:Poly(A)-Binding Proteins; D020033:Protein Isoforms; D014758:Viral Core Proteins