title: Replication of tobacco mosaic virus on endoplasmic reticulum and role of the cytoskeleton and virus movement protein in intracellular distribution of viral RNA.
abstract: Little is known about the mechanisms of intracellular targeting of viral nucleic acids within infected cells. We used in situ hybridization to visualize the distribution of tobacco mosaic virus (TMV) viral RNA (vRNA) in infected tobacco protoplasts. Immunostaining of the ER lumenal binding protein (BiP) concurrent with in situ hybridization revealed that vRNA colocalized with the ER, including perinuclear ER. At midstages of infection, vRNA accumulated in large irregular bodies associated with cytoplasmic filaments while at late stages, vRNA was dispersed throughout the cytoplasm and was associated with hair-like protrusions from the plasma membrane containing ER. TMV movement protein (MP) and replicase colocalized with vRNA, suggesting that viral replication and translation occur in the same subcellular sites. Immunostaining with tubulin provided evidence of colocalization of vRNA with microtubules, while disruption of the cytoskeleton with pharmacological agents produced severe changes in vRNA localization. Mutants of TMV lacking functional MP accumulated vRNA, but the distribution of vRNA was different from that observed in wild-type infection. MP was not required for association of vRNA with perinuclear ER, but was required for the formation of the large irregular bodies and association of vRNA with the hair-like protrusions.
authors.affiliation: Division of Plant Biology, Department of Cell Biology, The Scripps Research Institute, La Jolla, California 92037, USA.
authors.forename: P
authors.initials: P
authors.lastname: Más
authors.forename: R N
authors.initials: RN
authors.lastname: Beachy
mesh_terms: D001692:Biological Transport / Q000235:genetics; D015152:Blotting, Northern; D003599:Cytoskeleton / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D004721:Endoplasmic Reticulum / Q000235:genetics / Q000378:metabolism / Q000502:physiology / Q000821:virology*; D016679:Genome, Viral; D017403:In Situ Hybridization; D007424:Intracellular Fluid / Q000378:metabolism*; D053830:Plant Viral Movement Proteins; D010947:Plants, Toxic; D012367:RNA, Viral / Q000378:metabolism*; D012324:RNA-Dependent RNA Polymerase / Q000378:metabolism; D013347:Subcellular Fractions / Q000378:metabolism / Q000821:virology; D014026:Nicotiana / Q000166:cytology* / Q000187:drug effects / Q000821:virology*; D014027:Tobacco Mosaic Virus / Q000235:genetics / Q000472:pathogenicity / Q000502:physiology*; D014764:Viral Proteins / Q000378:metabolism / Q000502:physiology*; D014779:Virus Replication / Q000235:genetics / Q000502:physiology*
chemical_list: D053830:Plant Viral Movement Proteins; D012367:RNA, Viral; D014764:Viral Proteins; D012324:RNA-Dependent RNA Polymerase