Deletion of the C-terminal ESEV domain of NS1 does not affect the replication of a low-pathogenic avian influenza virus H7N1 in ducks and chickens.
Highly pathogenic avian influenza (HPAI) H7N1 viruses caused a series of epizootics in Italy between 1999 and 2001. The emergence of these HPAI viruses coincided with the deletion of the six amino acids R(225)VESEV(230) at the C terminus of NS1. In order to assess how the truncation of NS1 affected virus replication, we used reverse genetics to generate a wild-type low-pathogenic avian influenza (LPAI) H7N1 virus with a 230aa NS1 (H7N1(230)) and a mutant virus with a truncated NS1 (H7N1(224)). The 6aa truncation had no impact on virus replication in duck or chicken cells in vitro. The H7N1(230) and H7N1(224) viruses also replicated to similar levels and induced similar immune responses in ducks or chickens. No significant histological lesions were detected in infected ducks, regardless of the virus inoculated. However, in chickens, the H7N1(230) virus induced a more severe interstitial pneumonia than did the H7N1(224) virus. These findings indicate that the C-terminal extremity of NS1, including the PDZ-binding motif ESEV, is dispensable for efficient replication of an LPAI virus in ducks and chickens, even though it may increase virulence in chickens, as revealed by the intensity of the histological lesions.
INRA, UMR 1225, Ecole nationale vétérinaire de Toulouse, F-31076 Toulouse, France.|Université de Toulouse, ENVT, UMR 1225, F-31076 Toulouse, France.
Sébastien M
SM
Soubies
Equipe BioVA, INRA UMR1282, Infectiologie et Santé Publique, ISP, F-37380 Nouzilly, France.|Université François Rabelais de Tours, UMR1282 Infectiologie et Santé Publique, F-37000 Tours, France.
Thomas W
TW
Hoffmann
INRA, UMR 1225, Ecole nationale vétérinaire de Toulouse, F-31076 Toulouse, France.|Université de Toulouse, ENVT, UMR 1225, F-31076 Toulouse, France.
Guillaume
G
Croville
INRA UMR 703, APEX, Oniris-La Chantrerie, F-44307 Nantes, France.
Thibaut
T
Larcher
INRA UMR 703, APEX, Oniris-La Chantrerie, F-44307 Nantes, France.
Mireille
M
Ledevin
Equipe BioVA, INRA UMR1282, Infectiologie et Santé Publique, ISP, F-37380 Nouzilly, France.|Université François Rabelais de Tours, UMR1282 Infectiologie et Santé Publique, F-37000 Tours, France.
Denis
D
Soubieux
Université François Rabelais de Tours, UMR1282 Infectiologie et Santé Publique, F-37000 Tours, France.|Equipe PIA, INRA UMR1282, Infectiologie et Santé Publique, ISP, F-37380 Nouzilly, France.
Pascale
P
Quéré
INRA, UMR 1225, Ecole nationale vétérinaire de Toulouse, F-31076 Toulouse, France.|Université de Toulouse, ENVT, UMR 1225, F-31076 Toulouse, France.
Jean-Luc
JL
Guérin
Equipe BioVA, INRA UMR1282, Infectiologie et Santé Publique, ISP, F-37380 Nouzilly, France.|Université François Rabelais de Tours, UMR1282 Infectiologie et Santé Publique, F-37000 Tours, France.
Daniel
D
Marc
INRA, UMR 1225, Ecole nationale vétérinaire de Toulouse, F-31076 Toulouse, France.|Université de Toulouse, ENVT, UMR 1225, F-31076 Toulouse, France.
Romain
R
Volmer
D000818:Animals; D002460:Cell Line; D002642:Chick Embryo; D002645:Chickens / Q000276:immunology / Q000821:virology*; D004372:Ducks / Q000276:immunology / Q000821:virology*; D057916:Influenza A Virus, H7N1 Subtype / Q000235:genetics* / Q000276:immunology / Q000378:metabolism*; D005585:Influenza in Birds / Q000235:genetics / Q000276:immunology / Q000378:metabolism* / Q000821:virology; D017384:Sequence Deletion / Q000235:genetics / Q000276:immunology; D017361:Viral Nonstructural Proteins / Q000235:genetics* / Q000276:immunology / Q000378:metabolism*; D014779:Virus Replication / Q000235:genetics / Q000276:immunology
D017361:Viral Nonstructural Proteins