title: Alfalfa mosaic virus replicase proteins, P1 and P2, localize to the tonoplast in the presence of virus RNA.
abstract: To identify the virus components important for assembly of the Alfalfa mosaic virus replicase complex, we used live cell imaging of Arabidopsis thaliana protoplasts that expressed various virus cDNAs encoding native and GFP-fusion proteins of P1 and P2 replicase proteins and full-length virus RNAs. Expression of P1-GFP alone resulted in fluorescent vesicle-like bodies in the cytoplasm that colocalized with FM4-64, an endocytic marker, and RFP-AtVSR2, RabF2a/Rha1-mCherry, and RabF2b/Ara7-mCherry, all of which localize to multivesicular bodies (MVBs), which are also called prevacuolar compartments, that mediate traffic to the lytic vacuole. GFP-P2 was driven from the cytosol to MVBs when expressed with P1 indicating that P1 recruited GFP-P2. P1-GFP localized on the tonoplast, which surrounds the vacuole, in the presence of infectious virus RNA, replication competent RNA2, or P2 and replication competent RNA1 or RNA3. This suggests that a functional replication complex containing P1, P2, and a full-length AMV RNA assembles on MVBs to traffic to the tonoplast.
authors.affiliation: Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN 47907, USA.
authors.forename: Amr
authors.initials: A
authors.lastname: Ibrahim
authors.forename: Heather M
authors.initials: HM
authors.lastname: Hutchens
authors.forename: R Howard
authors.initials: RH
authors.lastname: Berg
authors.forename: L Sue
authors.initials: LS
authors.lastname: Loesch-Fries
mesh_terms: D017794:Alfalfa mosaic virus / Q000201:enzymology* / Q000235:genetics / Q000502:physiology; D017360:Arabidopsis / Q000821:virology; D001483:Base Sequence; D022083:Cytoplasmic Structures / Q000821:virology; D004279:DNA, Viral / Q000235:genetics; D054884:Host-Pathogen Interactions; D012367:RNA, Viral / Q000235:genetics / Q000378:metabolism*; D012324:RNA-Dependent RNA Polymerase / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D014779:Virus Replication / Q000235:genetics / Q000502:physiology
chemical_list: D004279:DNA, Viral; D012367:RNA, Viral; D011993:Recombinant Fusion Proteins; D012324:RNA-Dependent RNA Polymerase