title: The open reading frame VI product of Cauliflower mosaic virus is a nucleocytoplasmic protein: its N terminus mediates its nuclear export and formation of electron-dense viroplasms.
abstract: The Cauliflower mosaic virus (CaMV) open reading frame VI product (P6) is essential for the viral infection cycle. It controls translation reinitiation of the viral polycistronic RNAs and forms cytoplasmic inclusion bodies (viroplasms) where virus replication and assembly occur. In this study, the mechanism involved in viroplasm formation was investigated by in vitro and in vivo experiments. Far protein gel blot assays using a collection of P6 deletion mutants demonstrated that the N-terminal alpha-helix of P6 mediates interaction between P6 molecules. Transient expression in tobacco (Nicotiana tabacum) BY-2 cells of full-length P6 and P6 mutants fused to enhanced green fluorescent protein revealed that viroplasms are formed at the periphery of the nucleus and that the N-terminal domain of P6 is an important determinant in this process. Finally, this study led to the unexpected finding that P6 is a nucleocytoplasmic shuttle protein and that its nuclear export is mediated by a Leu-rich sequence that is part of the alpha-helix domain implicated in viroplasm formation. The discovery that P6 can localize to the nucleus opens new prospects for understanding yet unknown roles of this viral protein in the course of the CaMV infection cycle.
authors.affiliation: Institut de Biologie Moléculaire des Plantes, Unité Propre de Recherche, Centre National de la Recherche Scientifique 2357, Université Louis Pasteur, 67084 Strasbourg Cedex, France.
authors.forename: Muriel
authors.initials: M
authors.lastname: Haas
authors.forename: Angèle
authors.initials: A
authors.lastname: Geldreich
authors.forename: Marina
authors.initials: M
authors.lastname: Bureau
authors.forename: Laurence
authors.initials: L
authors.lastname: Dupuis
authors.forename: Véronique
authors.initials: V
authors.lastname: Leh
authors.forename: Guillaume
authors.initials: G
authors.lastname: Vetter
authors.forename: Kappei
authors.initials: K
authors.lastname: Kobayashi
authors.forename: Thomas
authors.initials: T
authors.lastname: Hohn
authors.forename: Lyubov
authors.initials: L
authors.lastname: Ryabova
authors.forename: Pierre
authors.initials: P
authors.lastname: Yot
authors.forename: Mario
authors.initials: M
authors.lastname: Keller
mesh_terms: D021581:Active Transport, Cell Nucleus; D000595:Amino Acid Sequence; D001483:Base Sequence; D029741:Brassica rapa / Q000821:virology; D017796:Caulimovirus / Q000235:genetics* / Q000378:metabolism* / Q000472:pathogenicity; D004279:DNA, Viral / Q000235:genetics; D005814:Genes, Viral; D007181:Inclusion Bodies, Viral / Q000378:metabolism; D008958:Models, Molecular; D009154:Mutation; D029543:Nucleocytoplasmic Transport Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D016366:Open Reading Frames; D010935:Plant Diseases / Q000821:virology; D017434:Protein Structure, Tertiary; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D014026:Nicotiana / Q000821:virology; D015534:Trans-Activators / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D014764:Viral Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*
chemical_list: D004279:DNA, Viral; D029543:Nucleocytoplasmic Transport Proteins; D011993:Recombinant Fusion Proteins; D015534:Trans-Activators; D014764:Viral Proteins; C095687:gene VI protein, Cauliflower mosaic virus; C065790:viroplasmin protein, Cauliflower mosaic virus
references.citation: J Comput Biol. 1995 Spring;2(1):125-38
references.pmid: 7497115
references.citation: Mol Plant Microbe Interact. 2000 Nov;13(11):1275-9
references.pmid: 11059496
references.citation: Annu Rev Microbiol. 1998;52:491-532
references.pmid: 9891806
references.citation: Prog Nucleic Acid Res Mol Biol. 2002;72:1-39
references.pmid: 12206450
references.citation: Plant Physiol. 1995 Apr;107(4):1201-8
references.pmid: 7770524
references.citation: Mol Plant Pathol. 2002 Nov 1;3(6):419-29
references.pmid: 20569349
references.citation: J Gen Virol. 1999 Feb;80 ( Pt 2):333-9
references.pmid: 10073692
references.citation: J Cell Biol. 2001 Apr 30;153(3):449-55
references.pmid: 11331297
references.citation: Virology. 1991 Nov;185(1):337-44
references.pmid: 1656590
references.citation: J Cell Biol. 1998 Dec 28;143(7):1883-98
references.pmid: 9864362
references.citation: Annu Rev Cell Dev Biol. 1999;15:607-60
references.pmid: 10611974
references.citation: Virus Genes. 1996;13(1):5-17
references.pmid: 8938975
references.citation: Mol Plant Microbe Interact. 2001 Jan;14(1):31-41
references.pmid: 11194869
references.citation: Mol Plant Microbe Interact. 1990 Sep-Oct;3(5):341-5
references.pmid: 2134858
references.citation: Virology. 1980 Apr 30;102(2):381-8
references.pmid: 18631647
references.citation: Plasmid. 1983 Jan;9(1):31-41
references.pmid: 6300943
references.citation: J Mol Appl Genet. 1984;2(6):537-47
references.pmid: 6530602
references.citation: Curr Biol. 2002 Jan 8;12(1):1-11
references.pmid: 11790298
references.citation: Virology. 1989 Apr;169(2):436-46
references.pmid: 2705305
references.citation: Mol Plant Microbe Interact. 1998 Jul;11(7):618-25
references.pmid: 9650295
references.citation: Cell. 2001 Jan 26;104(2):173-6
references.pmid: 11207359
references.citation: J Virol. 2003 Aug;77(15):8577-83
references.pmid: 12857928
references.citation: Trends Cell Biol. 2000 Dec;10(12):524-30
references.pmid: 11121744
references.citation: Curr Opin Struct Biol. 1997 Jun;7(3):388-93
references.pmid: 9204281
references.citation: Mol Cell Biol. 1986 Jul;6(7):2632-7
references.pmid: 3785205
references.citation: Virology. 1998 Mar 15;242(2):395-402
references.pmid: 9514961
references.citation: Virology. 2000 Jan 5;266(1):1-7
references.pmid: 10612654
references.citation: J Cell Biol. 1975 Dec;67(3):835-51
references.pmid: 811671
references.citation: Curr Opin Cell Biol. 2002 Jun;14(3):328-35
references.pmid: 12067655
references.citation: EMBO J. 1995 Jul 17;14(14):3552-62
references.pmid: 7628455
references.citation: EMBO J. 1993 Aug;12(8):3305-14
references.pmid: 8344266
references.citation: Virology. 1996 Mar 1;217(1):147-57
references.pmid: 8599199
references.citation: J Gen Virol. 2004 Dec;85(Pt 12):3765-75
references.pmid: 15557250
references.citation: Mol Plant Microbe Interact. 1997 Dec;10(9):1094-101
references.pmid: 9390424
references.citation: J Cell Sci. 1994 Feb;107 ( Pt 2):385-99
references.pmid: 8207070
references.citation: Nucleic Acids Res. 1998 Apr 1;26(7):1834-40
references.pmid: 9512560
references.citation: Cell. 2001 Sep 21;106(6):723-33
references.pmid: 11572778
references.citation: Phytopathology. 2002 Feb;92(2):190-6
references.pmid: 18943093
references.citation: Adv Virus Res. 1994;44:1-67
references.pmid: 7817872
references.citation: Mol Plant Microbe Interact. 2002 Oct;15(10):1050-7
references.pmid: 12437303
references.citation: Plant Cell. 1999 Jul;11(7):1267-76
references.pmid: 10402428
references.citation: Proc Natl Acad Sci U S A. 2002 Feb 19;99(4):2422-7
references.pmid: 11842201
references.citation: Microbiol Immunol. 1998;42(1):65-9
references.pmid: 9525783
references.citation: Mol Plant Microbe Interact. 1999 May;12(5):377-84
references.pmid: 10226370
references.citation: EMBO J. 2002 Feb 1;21(3):377-86
references.pmid: 11823430
references.citation: Nat Rev Mol Cell Biol. 2003 Aug;4(8):605-12
references.pmid: 12923522
references.citation: Cell. 1997 Sep 19;90(6):1051-60
references.pmid: 9323133
references.citation: Exp Cell Res. 1998 Aug 1;242(2):540-7
references.pmid: 9683540