title: PB2 subunit of avian influenza virus subtype H9N2: a pandemic risk factor.
abstract: Avian influenza viruses of subtype H9N2 that are found worldwide are occasionally transmitted to humans and pigs. Furthermore, by co-circulating with other influenza subtypes, they can generate new viruses with the potential to also cause zoonotic infections, as observed in 1997 with H5N1 or more recently with H7N9 and H10N8 viruses. Comparative analysis of the adaptive mutations in polymerases of different viruses indicates that their impact on the phylogenetically related H9N2 and H7N9 polymerases is higher than on the non-related H7N7 and H1N1pdm09 polymerases. Analysis of polymerase reassortants composed of subunits of different viruses demonstrated that the efficient enhancement of polymerase activity by H9N2-PB2 does not depend on PA and PB1. These observations suggest that the PB2 subunit of the H9N2 polymerase has a high adaptive potential and may therefore be an important pandemic risk factor.
authors.affiliation: Institute of Virology, Philipps University, Hans-Meerwein-Straße 2, 35043 Marburg, Germany.
authors.forename: Hanna
authors.initials: H
authors.lastname: Sediri
authors.affiliation: Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Martinistraße 52, 20251 Hamburg, Germany.
authors.forename: Swantje
authors.initials: S
authors.lastname: Thiele
authors.affiliation: Institute of Virology, Philipps University, Hans-Meerwein-Straße 2, 35043 Marburg, Germany.
authors.forename: Folker
authors.initials: F
authors.lastname: Schwalm
authors.affiliation: Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Martinistraße 52, 20251 Hamburg, Germany.
authors.forename: Gülsah
authors.initials: G
authors.lastname: Gabriel
authors.affiliation: Institute of Virology, Philipps University, Hans-Meerwein-Straße 2, 35043 Marburg, Germany.
authors.forename: Hans-Dieter
authors.initials: HD
authors.lastname: Klenk
mesh_terms: D000220:Adaptation, Biological; D000818:Animals; D001717:Birds; D005260:Female; D006801:Humans; D053127:Influenza A Virus, H9N2 Subtype / Q000201:enzymology* / Q000235:genetics; D005585:Influenza in Birds / Q000821:virology*; D050505:Mutant Proteins / Q000235:genetics / Q000378:metabolism; D020125:Mutation, Missense; D012324:RNA-Dependent RNA Polymerase / Q000235:genetics / Q000378:metabolism*; D016865:Reassortant Viruses / Q000201:enzymology / Q000235:genetics; D013552:Swine; D014764:Viral Proteins / Q000235:genetics / Q000378:metabolism*; D037521:Virulence Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D050505:Mutant Proteins; C057027:PB2 protein, Influenzavirus A; D014764:Viral Proteins; D037521:Virulence Factors; D012324:RNA-Dependent RNA Polymerase