title: Analysis of potato virus X replicase and TGBp3 subcellular locations.
abstract: Potato virus X (PVX) infection leads to certain cytopathological modifications of the host endomembrane system. The subcellular location of the PVX replicase was previously unknown while the PVX TGBp3 protein was previously reported to reside in the ER. Using PVX infectious clones expressing the green fluorescent protein reporter, and antisera detecting the PVX replicase and host membrane markers, we examined the subcellular distribution of the PVX replicase in relation to the TGBp3. Confocal and electron microscopic observations revealed that the replicase localizes in membrane bound structures that derive from the ER. A subset of TGBp3 resides in the ER at the same location as the replicase. Sucrose gradient fractionation showed that the PVX replicase and TGBp3 proteins co-fractionate with ER marker proteins. This localization represents a region where both proteins may be synthesized and/or function. There is no evidence to indicate that either PVX protein moves into the Golgi apparatus. Cerulenin, a drug that inhibits de novo membrane synthesis, also inhibited PVX replication. These combined data indicate that PVX replication relies on ER-derived membrane recruitment and membrane proliferation.
authors.affiliation: Department of Entomology and Plant Pathology, Noble Research Center, Oklahoma State University, Stillwater, OK 74078, USA. dbamu001@ucr.edu
authors.forename: Devinka
authors.initials: D
authors.lastname: Bamunusinghe
authors.forename: Cynthia L
authors.initials: CL
authors.lastname: Hemenway
authors.forename: Richard S
authors.initials: RS
authors.lastname: Nelson
authors.forename: Anton A
authors.initials: AA
authors.lastname: Sanderfoot
authors.forename: Chang M
authors.initials: CM
authors.lastname: Ye
authors.forename: Muniwarage A T
authors.initials: MA
authors.lastname: Silva
authors.forename: M
authors.initials: M
authors.lastname: Payton
authors.forename: Jeanmarie
authors.initials: J
authors.lastname: Verchot-Lubicz
mesh_terms: D002462:Cell Membrane / Q000821:virology; D002569:Cerulenin / Q000494:pharmacology; D004721:Endoplasmic Reticulum / Q000378:metabolism / Q000821:virology*; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D018613:Microscopy, Confocal; D046529:Microscopy, Electron, Transmission; D018515:Plant Leaves / Q000648:ultrastructure / Q000821:virology; D017863:Potexvirus / Q000235:genetics / Q000378:metabolism*; D011523:Protoplasts / Q000821:virology; D012324:RNA-Dependent RNA Polymerase / Q000235:genetics / Q000378:metabolism*; D014026:Nicotiana / Q000821:virology; D014764:Viral Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D014764:Viral Proteins; D049452:Green Fluorescent Proteins; D002569:Cerulenin; D012324:RNA-Dependent RNA Polymerase