title: The Cucumber leaf spot virus p25 auxiliary replicase protein binds and modifies the endoplasmic reticulum via N-terminal transmembrane domains.
abstract: Cucumber leaf spot virus (CLSV) is a member of the Aureusvirus genus, family Tombusviridae. The auxiliary replicase of Tombusvirids has been found to localize to endoplasmic reticulum (ER), peroxisomes or mitochondria; however, localization of the auxiliary replicase of aureusviruses has not been determined. We have found that the auxiliary replicase of CLSV (p25) fused to GFP colocalizes with ER and that three predicted transmembrane domains (TMDs) at the N-terminus of p25 are sufficient for targeting, although the second and third TMDs play the most prominent roles. Confocal analysis of CLSV infected 16C plants shows that the ER becomes modified including the formation of punctae at connections between ER tubules and in association with the nucleus. Ultrastructural analysis shows that the cytoplasm contains numerous vesicles which are also found between the perinuclear ER and nuclear membrane. It is proposed that these vesicles correspond to modified ER used as sites for CLSV replication.
authors.affiliation: University of British Columbia, Faculty of Land and Food Systems, Vancouver, British Columbia, Canada V6T 1Z4.
authors.forename: Kankana
authors.initials: K
authors.lastname: Ghoshal
authors.affiliation: Agriculture and Agri-Food Canada Pacific Agri-Food Research Centre, 4200 Hwy 97, Summerland, British Columbia, Canada V0H 1Z0.
authors.forename: Jane
authors.initials: J
authors.lastname: Theilmann
authors.affiliation: Agriculture and Agri-Food Canada Pacific Agri-Food Research Centre, 4200 Hwy 97, Summerland, British Columbia, Canada V0H 1Z0.
authors.forename: Ron
authors.initials: R
authors.lastname: Reade
authors.affiliation: Agriculture and Agri-Food Canada Pacific Agri-Food Research Centre, 4200 Hwy 97, Summerland, British Columbia, Canada V0H 1Z0.
authors.forename: Helene
authors.initials: H
authors.lastname: Sanfacon
authors.affiliation: University of British Columbia, Faculty of Land and Food Systems, Vancouver, British Columbia, Canada V6T 1Z4; Agriculture and Agri-Food Canada Pacific Agri-Food Research Centre, 4200 Hwy 97, Summerland, British Columbia, Canada V0H 1Z0. Electronic address: dann.rochon@agr.gc.ca.
authors.forename: D'Ann
authors.initials: D
authors.lastname: Rochon
mesh_terms: D000595:Amino Acid Sequence; D004721:Endoplasmic Reticulum / Q000201:enzymology / Q000378:metabolism*; D015967:Gene Expression Regulation, Viral / Q000502:physiology; D008969:Molecular Sequence Data; D017434:Protein Structure, Tertiary; D012324:RNA-Dependent RNA Polymerase / Q000378:metabolism*; D014026:Nicotiana; D019183:Tombusviridae / Q000201:enzymology* / Q000235:genetics / Q000502:physiology; D014764:Viral Proteins / Q000235:genetics / Q000378:metabolism*; D014779:Virus Replication
chemical_list: D014764:Viral Proteins; D012324:RNA-Dependent RNA Polymerase
keywords: Aureusvirus; Auxiliary replicase; Endoplasmic reticulum; Tombusviridae