title: Norwalk virus N-terminal nonstructural protein is associated with disassembly of the Golgi complex in transfected cells.
abstract: Norwalk virus is the prototype strain for members of the genus Norovirus in the family Caliciviridae, which are associated with epidemic gastroenteritis in humans. The nonstructural protein encoded in the N-terminal region of the first open reading frame (ORF1) of the Norwalk virus genome is analogous in gene order to proteins 2A and 2B of the picornaviruses; the latter is known for its membrane-associated activities. Confocal microscopy imaging of cells transfected with a vector plasmid that provided expression of the entire Norwalk virus N-terminal protein (amino acids 1 to 398 of the ORF1 polyprotein) showed colocalization of this protein with cellular proteins of the Golgi apparatus. Furthermore, this colocalization was characteristically associated with a visible disassembly of the Golgi complex into discrete aggregates. Deletion of a predicted hydrophobic region (amino acids 360 to 379) in a potential 2B-like (2BL) region (amino acids 301 to 398) near the C terminus of the Norwalk virus N-terminal protein reduced Golgi colocalization and disassembly. Confocal imaging was conducted to examine the expression characteristics of fusion proteins in which the 2BL region from the N-terminal protein of Norwalk virus (a genogroup I norovirus) or MD145 (a genogroup II norovirus) was fused to the C terminus of enhanced green fluorescent protein. Expression of each fusion protein in cells showed evidence for its colocalization with the Golgi apparatus. These data indicate that the N-terminal protein of Norwalk virus interacts with the Golgi apparatus and may play a 2BL role in the induction of intracellular membrane rearrangements associated with positive-strand RNA virus replication in cells.
authors.affiliation: Laboratory of Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA.
authors.forename: Virneliz
authors.initials: V
authors.lastname: Fernandez-Vega
authors.forename: Stanislav V
authors.initials: SV
authors.lastname: Sosnovtsev
authors.forename: Gaël
authors.initials: G
authors.lastname: Belliot
authors.forename: Adriene D
authors.initials: AD
authors.lastname: King
authors.forename: Tanaji
authors.initials: T
authors.lastname: Mitra
authors.forename: Alexander
authors.initials: A
authors.lastname: Gorbalenya
authors.forename: Kim Y
authors.initials: KY
authors.lastname: Green
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002415:Cats; D002460:Cell Line; D017353:Gene Deletion; D006056:Golgi Apparatus / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D057927:Hydrophobic and Hydrophilic Interactions; D018613:Microscopy, Confocal; D008856:Microscopy, Fluorescence; D008969:Molecular Sequence Data; D009663:Norwalk virus / Q000472:pathogenicity*; D014162:Transfection; D017361:Viral Nonstructural Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: D017361:Viral Nonstructural Proteins