title: [Virological impact of stalk region of neuraminidase in influenza A/Anhui/1/05 (H5N1) and A/Ohio/07/2009 (H1N1) viruses].
abstract: This study aims to investigate the virological impact of the stalk region and cysteine (C) in neuraminidase (NA) of influenza A/Anhui/1/05 (H5N1) and A/Ohio/07/2009 (H1N1) viruses. The NA of A/ Anhui/1/05 (H5N1), defined as AH N1, lacked 20 amino acids (including C, defined as s20) as compared with NA of A/Ohio/07/2009 (H1N1) (defined as 09N1). We deleted s20 of 09N1 to construct 09N1-s20, and inserted s20 into AH N1 to construct AH N1+s20. To investigate the impact of C on the biological function of NA, we deleted C in 09N1 to construct 09N1-C and inserted C into AH N1 to construct AH N1-C. The pseudo-type viral particle (pp) system was used to evaluate the impact of these mutants on virology. The combination of 09N1-C and 09H1 (defined as 09H1::09N1-C) showed an infectivity 8 times that of the wild type 09H1::09N1, while the infectivity of the combination of AH N1+C and AH H5 (defined as AH H5::AH N1+C) was much lower than that of the wild type AH H5::AH N1. The infectivity of the combination of 09N1-s20 and 09H1 (defined as 09H1::09N1-s20) was 4 times that of the wild type 09H1::09N1; the infectivity of the combination of AH N1+s20 and AH H5 (defined as AH H5:: AH N1+s20) was 1/7 that of the wild type AH H5::AH N1. The co-existence of 09N1-C and AH H5 displayed 6 times the infectivity of AH H5::09N1, while the infectivity of 09H1::AH N1+C was very low. Multimer analysis showed that in the wild type 09N1, the forms of NA were dimer >> tetramer > monomer; the major component of NA in 09N1-C was monomer; in 09N1-s20, the forms of NA were monomer >> dimer. AH N1 was mainly composed of monomer; in AH N1+s20, the forms of NA were dimer >> monomer > tetramer; in AH N1+C, the forms of NA were dimer >> tetramer. Deletion of C or s20 from 09N1 did not change the expression of NA. The study suggested that deletion of C from the stalk region of NA in A/Ohio/07/2009 (H1N1) increases infectivity. Insertion of C into NA's stalk region of A/ Anhui/1/05 (H5N1) significantly decreases infectivity. Cysteine deletion in the stalk region is important for the infectivity of A/Anhui/1/05 (H5N1) and A/Ohio/07/2009 (H1N1). It may interfere with the infectivity via changes in NA polymerization.
authors.forename: Jia
authors.initials: J
authors.lastname: Wu
authors.forename: Ting
authors.initials: T
authors.lastname: Wang
authors.forename: Liu
authors.initials: L
authors.lastname: Zhang
authors.forename: Zhi-Han
authors.initials: ZH
authors.lastname: Ye
authors.forename: Jian-Xin
authors.initials: JX
authors.lastname: Lv
mesh_terms: D020816:Amino Acid Motifs; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype / Q000737:chemistry / Q000201:enzymology* / Q000235:genetics / Q000472:pathogenicity*; D053124:Influenza A Virus, H5N1 Subtype / Q000737:chemistry / Q000201:enzymology* / Q000235:genetics / Q000472:pathogenicity*; D007251:Influenza, Human / Q000821:virology*; D009439:Neuraminidase / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D014764:Viral Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D014774:Virulence
chemical_list: D014764:Viral Proteins; C487630:NA protein, influenza A virus; D009439:Neuraminidase