title: The cytoplasmic location of chicken mx is not the determining factor for its lack of antiviral activity.
abstract: BACKGROUND
  Chicken Mx belongs to the Mx family of interferon-induced dynamin-like GTPases, which in some species possess potent antiviral properties. Conflicting data exist for the antiviral capability of chicken Mx. Reports of anti-influenza activity of alleles encoding an Asn631 polymorphism have not been supported by subsequent studies. The normal cytoplasmic localisation of chicken Mx may influence its antiviral capacity. Here we report further studies to determine the antiviral potential of chicken Mx against Newcastle disease virus (NDV), an economically important cytoplasmic RNA virus of chickens, and Thogoto virus, an orthomyxovirus known to be exquisitely sensitive to the cytoplasmic MxA protein from humans. We also report the consequences of re-locating chicken Mx to the nucleus.
  
  
  RESULTS
  Chicken Mx was tested in virus infection assays using NDV. Neither the Asn631 nor Ser631 Mx alleles (when transfected into 293T cells) showed inhibition of virus-directed gene expression when the cells were subsequently infected with NDV. Human MxA however did show significant inhibition of NDV-directed gene expression. Chicken Mx failed to inhibit a Thogoto virus (THOV) minireplicon system in which the cytoplasmic human MxA protein showed potent and specific inhibition. Relocalisation of chicken Mx to the nucleus was achieved by inserting the Simian Virus 40 large T antigen nuclear localisation sequence (SV40 NLS) at the N-terminus of chicken Mx. Nuclear re-localised chicken Mx did not inhibit influenza (A/PR/8/34) gene expression during virus infection in cell culture or influenza polymerase activity in A/PR/8/34 or A/Turkey/50-92/91 minireplicon systems.
  
  
  CONCLUSIONS
  The chicken Mx protein (Asn631) lacks inhibitory effects against THOV and NDV, and is unable to suppress influenza replication when artificially re-localised to the cell nucleus. Thus, the natural cytoplasmic localisation of the chicken Mx protein does not account for its lack of antiviral activity.
authors.affiliation: Department of Veterinary Medicine, University of Cambridge, Cambridge, United Kingdom. c.benfield@imperial.ac.uk
authors.forename: Camilla T O
authors.initials: CT
authors.lastname: Benfield
authors.forename: Jon W
authors.initials: JW
authors.lastname: Lyall
authors.forename: Laurence S
authors.initials: LS
authors.lastname: Tiley
mesh_terms: D000483:Alleles; D000818:Animals; D000998:Antiviral Agents / Q000378:metabolism* / Q000494:pharmacology*; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism; D002645:Chickens; D003593:Cytoplasm / Q000378:metabolism*; D019204:GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology*; D006801:Humans; D053124:Influenza A Virus, H5N1 Subtype / Q000187:drug effects / Q000502:physiology; D051379:Mice; D064547:Myxovirus Resistance Proteins; D009522:Newcastle disease virus / Q000187:drug effects; D011110:Polymorphism, Genetic / Q000235:genetics; D021381:Protein Transport; D018117:Thogotovirus / Q000187:drug effects; D018116:Vesiculovirus / Q000187:drug effects; D014779:Virus Replication / Q000187:drug effects
chemical_list: D000998:Antiviral Agents; C579071:MX1 protein, human; C579070:Mx1 protein, mouse; D064547:Myxovirus Resistance Proteins; D019204:GTP-Binding Proteins
references.citation: Microbiol Immunol. 2002;46(1):29-36
references.pmid: 11911186
references.citation: J Biol Chem. 2009 May 29;284(22):15206-14
references.pmid: 19297326
references.citation: J Virol. 2001 Oct;75(19):9282-6
references.pmid: 11533190
references.citation: Virology. 1985 Jan 15;140(1):192-6
references.pmid: 3880978
references.citation: Biochem Biophys Res Commun. 2004 Oct 15;323(2):541-6
references.pmid: 15369785
references.citation: Proc Natl Acad Sci U S A. 2007 Apr 17;104(16):6806-11
references.pmid: 17426143
references.citation: J Virol. 2003 Jan;77(2):1501-11
references.pmid: 12502864
references.citation: J Virol. 1997 Apr;71(4):2591-9
references.pmid: 9060610
references.citation: J Virol. 1994 Nov;68(11):6910-7
references.pmid: 7933071
references.citation: J Gen Virol. 2007 Apr;88(Pt 4):1319-1323
references.pmid: 17374778
references.citation: Cell. 1984 Dec;39(3 Pt 2):499-509
references.pmid: 6096007
references.citation: J Virol. 1993 Aug;67(8):4760-8
references.pmid: 8392613
references.citation: J Virol. 1992 Apr;66(4):2564-9
references.pmid: 1548781
references.citation: EMBO J. 1992 Apr;11(4):1657-61
references.pmid: 1314172
references.citation: J Interferon Cytokine Res. 1995 Jan;15(1):47-53
references.pmid: 7648434
references.citation: Cell. 1990 Jul 13;62(1):51-61
references.pmid: 2194673
references.citation: Gene. 1988 Jun 15;66(1):1-10
references.pmid: 3417148
references.citation: J Virol. 1990 Dec;64(12):6263-9
references.pmid: 2173790
references.citation: J Virol. 1995 Jul;69(7):4506-10
references.pmid: 7769712
references.citation: J Gen Virol. 2004 Dec;85(Pt 12):3689-3698
references.pmid: 15557242
references.citation: Gene. 1991 Dec 15;108(2):193-9
references.pmid: 1660837
references.citation: Avian Dis. 2007 Mar;51(1 Suppl):393-5
references.pmid: 17494592
references.citation: Am J Vet Res. 2007 Sep;68(9):988-94
references.pmid: 17764414
references.citation: Proc Soc Exp Biol Med. 1964 Jun;116:506-9
references.pmid: 14193387
references.citation: J Virol. 1993 Mar;67(3):1653-7
references.pmid: 8382314
references.citation: Mol Cell Biol. 1985 Aug;5(8):2150-3
references.pmid: 3939324
references.citation: Proc Natl Acad Sci U S A. 2004 Jun 15;101(24):8957-62
references.pmid: 15184662
references.citation: J Virol. 2007 Oct;81(19):10818-21
references.pmid: 17652381
references.citation: Genome Res. 2002 Apr;12(4):595-601
references.pmid: 11932243
references.citation: Virology. 1977 Nov;83(1):150-62
references.pmid: 18625483
references.citation: J Biol Chem. 2005 May 13;280(19):19393-400
references.pmid: 15757897
references.citation: Virology. 1993 Jul;195(1):100-12
references.pmid: 8100373
references.citation: J Virol. 2008 Apr;82(7):3624-31
references.pmid: 18199636
references.citation: Proc Natl Acad Sci U S A. 1983 Apr;80(7):1910-4
references.pmid: 6188159
references.citation: J Virol. 1995 Jun;69(6):3904-9
references.pmid: 7745744
references.citation: J Interferon Cytokine Res. 2007 Oct;27(10):847-55
references.pmid: 17970694
references.citation: Virology. 1996 Jun 15;220(2):330-8
references.pmid: 8661384
references.citation: Traffic. 2004 Dec;5(12):979-92
references.pmid: 15522099
references.citation: Cell. 1986 Jan 17;44(1):147-58
references.pmid: 3000619
references.citation: Virology. 2008 Oct 10;380(1):152-6
references.pmid: 18723201
references.citation: J Virol Methods. 2003 Mar;108(1):19-28
references.pmid: 12565150
references.citation: J Virol. 2003 Aug;77(16):8676-85
references.pmid: 12885886
references.citation: Virology. 2007 Jun 20;363(1):166-73
references.pmid: 17307214
references.citation: J Interferon Cytokine Res. 2006 Sep;26(9):650-60
references.pmid: 16978069
references.citation: J Virol. 2000 Jan;74(1):560-3
references.pmid: 10590150
references.citation: J Virol. 1993 Nov;67(11):6726-32
references.pmid: 8411374
references.citation: J Virol. 2008 Aug;82(15):7533-9
references.pmid: 18508886
references.citation: J Virol. 1985 Oct;56(1):201-6
references.pmid: 2411949
references.citation: J Virol. 2001 May;75(10):4823-31
references.pmid: 11312354
references.citation: Rev Sci Tech. 2009 Apr;28(1):219-31
references.pmid: 19618628
references.citation: Immunogenetics. 2008 Nov;60(11):689-97
references.pmid: 18726592
references.citation: FEBS Lett. 1999 Dec 10;463(1-2):24-8
references.pmid: 10601631
references.citation: Anim Genet. 2004 Apr;35(2):119-22
references.pmid: 15025571
references.citation: Nucleic Acids Res. 2004 Jan 29;32(2):643-52
references.pmid: 14752052
references.citation: J Virol. 1990 Jul;64(7):3370-5
references.pmid: 2161946
references.citation: Virology. 1962 Feb;16:203-4
references.pmid: 14465449