title: Heat shock 70 protein interaction with Turnip mosaic virus RNA-dependent RNA polymerase within virus-induced membrane vesicles.
abstract: Tandem affinity purification was used in Arabidopsis thaliana to identify cellular interactors of Turnip mosaic virus (TuMV) RNA-dependent RNA polymerase (RdRp). The heat shock cognate 70-3 (Hsc70-3) and poly(A)-binding (PABP) host proteins were recovered and shown to interact with the RdRp in vitro. As previously shown for PABP, Hsc70-3 was redistributed to nuclear and membranous fractions in infected plants and both RdRp interactors were co-immunoprecipitated from a membrane-enriched extract using RdRp-specific antibodies. Fluorescently tagged RdRp and Hsc70-3 localized to the cytoplasm and the nucleus when expressed alone or in combination in Nicotiana benthamiana. However, they were redistributed to large perinuclear ER-derived vesicles when co-expressed with the membrane binding 6K-VPg-Pro protein of TuMV. The association of Hsc70-3 with the RdRp could possibly take place in membrane-derived replication complexes. Thus, Hsc70-3 and PABP2 are potentially integral components of the replicase complex and could have important roles to play in the regulation of potyviral RdRp functions.
authors.affiliation: Department of Plant Science, McGill University, 21,111 Lakeshore, Ste-Anne-de-Bellevue, Quebec, Canada H9X 3V9.
authors.forename: Philippe J
authors.initials: PJ
authors.lastname: Dufresne
authors.forename: Karine
authors.initials: K
authors.lastname: Thivierge
authors.forename: Sophie
authors.initials: S
authors.lastname: Cotton
authors.forename: Chantal
authors.initials: C
authors.lastname: Beauchemin
authors.forename: Christine
authors.initials: C
authors.lastname: Ide
authors.forename: Eliane
authors.initials: E
authors.lastname: Ubalijoro
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Laliberté
authors.forename: Marc G
authors.initials: MG
authors.lastname: Fortin
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000821:virology*; D002467:Cell Nucleus / Q000737:chemistry; D003593:Cytoplasm / Q000737:chemistry; D050883:HSC70 Heat-Shock Proteins / Q000378:metabolism*; D047468:Immunoprecipitation; D008856:Microscopy, Fluorescence; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000378:metabolism*; D011485:Protein Binding; D025941:Protein Interaction Mapping; D012324:RNA-Dependent RNA Polymerase / Q000378:metabolism*; D014026:Nicotiana / Q000821:virology; D022161:Transport Vesicles / Q000821:virology*; D017806:Tymovirus / Q000378:metabolism*; D014764:Viral Proteins / Q000378:metabolism*
chemical_list: D050883:HSC70 Heat-Shock Proteins; D010940:Plant Proteins; D014764:Viral Proteins; D012324:RNA-Dependent RNA Polymerase