title: Characterization of neuraminidases from the highly pathogenic avian H5N1 and 2009 pandemic H1N1 influenza A viruses.
abstract: To study the precise role of the neuraminidase (NA), and its stalk region in particular, in the assembly, release, and entry of influenza virus, we deleted the 20-aa stalk segment from 2009 pandemic H1N1 NA (09N1) and inserted this segment, now designated 09s60, into the stalk region of a highly pathogenic avian influenza (HPAI) virus H5N1 NA (AH N1). The biological characterization of these wild-type and mutant NAs was analyzed by pseudotyped particles (pseudoparticles) system. Compared with the wild-type AH N1, the wild-type 09N1 exhibited higher NA activity and released more pseudoparticles. Deletion/insertion of the 09s60 segment did not alter this relationship. The infectivity of pseudoparticles harboring NA in combination with the hemagglutinin from HPAI H5N1 (AH H5) was decreased by insertion of 09s60 into AH N1 and was increased by deletion of 09s60 from 09N1. When isolated from the wild-type 2009H1N1 virus, 09N1 existed in the forms (in order of abundance) dimer>>tetramer>monomer, but when isolated from pseudoparticles, 09N1 existed in the forms dimer>monomer>>>tetramer. After deletion of 09s60, 09N1 existed in the forms monomer>>>dimer. AH N1 from pseudoparticles existed in the forms monomer>>dimer, but after insertion of 09s60, it existed in the forms dimer>>monomer. Deletion/insertion of 09s60 did not alter the NA glycosylation pattern of 09N1 or AH N1. The 09N1 was more sensitive than the AH N1 to the NA inhibitor oseltamivir, suggesting that the infectivity-enhancing effect of oseltamivir correlates with robust NA activity.
authors.affiliation: Key Laboratory for Laboratory Medicine, Ministry of Education, School of Laboratory Medicine and Life Science, Wenzhou Medical College, Wenzhou, People's Republic of China.
authors.forename: Jia
authors.initials: J
authors.lastname: Wu
authors.forename: Fengwei
authors.initials: F
authors.lastname: Zhang
authors.forename: Maorong
authors.initials: M
authors.lastname: Wang
authors.forename: Chunqiong
authors.initials: C
authors.lastname: Xu
authors.forename: Jingdong
authors.initials: J
authors.lastname: Song
authors.forename: Jianfang
authors.initials: J
authors.lastname: Zhou
authors.forename: Xiaojing
authors.initials: X
authors.lastname: Lin
authors.forename: Yonghui
authors.initials: Y
authors.lastname: Zhang
authors.forename: Xiaobing
authors.initials: X
authors.lastname: Wu
authors.forename: Wenjie
authors.initials: W
authors.lastname: Tan
authors.forename: Jian
authors.initials: J
authors.lastname: Lu
authors.forename: Honglan
authors.initials: H
authors.lastname: Zhao
authors.forename: Jimin
authors.initials: J
authors.lastname: Gao
authors.forename: Ping
authors.initials: P
authors.lastname: Zhao
authors.forename: Jianxin
authors.initials: J
authors.lastname: Lu
authors.forename: Yue
authors.initials: Y
authors.lastname: Wang
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000998:Antiviral Agents / Q000494:pharmacology; D001717:Birds; D019281:Dimerization; D017353:Gene Deletion; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype / Q000378:metabolism*; D053124:Influenza A Virus, H5N1 Subtype / Q000378:metabolism*; D005585:Influenza in Birds / Q000821:virology; D007251:Influenza, Human / Q000821:virology; D046529:Microscopy, Electron, Transmission / Q000379:methods; D008969:Molecular Sequence Data; D009154:Mutation; D009439:Neuraminidase / Q000037:antagonists & inhibitors / Q000737:chemistry*; D053139:Oseltamivir / Q000494:pharmacology; D017434:Protein Structure, Tertiary; D017386:Sequence Homology, Amino Acid
chemical_list: D000998:Antiviral Agents; D053139:Oseltamivir; D009439:Neuraminidase