title: [MECHANISMS OF ATTENUATION OF COLD-ADAPTED STRAIN A/KRASNO- DAR/101/35/59 (H2N2)].
abstract: OBJECTIVE
  Study of mechanisms of attenuation of cold-adapted (ca) influenza virus strain A/ Krasnodar/101/35/59 (H2N2), associated with disruption of NS1 protein functions.
  
  
  METHODS
  Study of interferonogenic activity of ca strain A/Krasnodar/101/35/59 (H2N2), its parent variant A/Krasnodar/101/59 (H2N2), virulent strain A/WSN/33 (H1N1) and a number of single gene and multiple gene reassortants between these strains, obtained using reverse genetics, was carried out. Study of dynamics of IFNβ gene expression was carried out by using a methodical approach of RT-PCR in real time mode.
  
  
  RESULTS
  Inclusion of PB-1 gene of ca strain A/ Krasnodar/101/35/59 (H2N2) with reversion to wild type into genome composition of virulent strain A/WSN/33 (H1N1) does not result in a sharp change of interferonogenic activity of the reassortant. At the same time, similar inclusion of PB-1 gene of ca strain resulted in an incredible growth of interferonogenic activity of the reassortant. On the other hand, inclusion of NP-gene of wild type strain A/Krasnodar/101/59 (H2N2) into genome composition of the wild type strain A/WSN/33 did not differ by effect on interferonogenicity of the reassortant from inclusion of NP-gene of ca strain.
  
  
  CONCLUSIONS
  Both constellations of genes of parent variants and mutations localized in these genes could affect formation of attenuation phenotype of reassortants. The data obtained allow to assume possible mechanisms of attenuation of ca strains, associated with disruption.of NS gene function.
authors.forename: S G
authors.initials: SG
authors.lastname: Markushin
authors.forename: O A
authors.initials: OA
authors.lastname: Svitich
authors.forename: A R
authors.initials: AR
authors.lastname: Kinkulkina
authors.forename: I B
authors.initials: IB
authors.lastname: Koptyaeva
authors.forename: K V
authors.initials: KV
authors.lastname: Lisovskaya
mesh_terms: D000222:Adaptation, Physiological / Q000235:genetics; D000818:Animals; D002642:Chick Embryo; D003080:Cold Temperature; D005838:Genotype; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype / Q000235:genetics* / Q000472:pathogenicity / Q000502:physiology; D053121:Influenza A Virus, H2N2 Subtype / Q000235:genetics* / Q000472:pathogenicity / Q000502:physiology; D007372:Interferons / Q000096:biosynthesis; D009154:Mutation; D010641:Phenotype; D017361:Viral Nonstructural Proteins / Q000096:biosynthesis / Q000235:genetics*; D014779:Virus Replication / Q000235:genetics
chemical_list: C108309:NS protein, influenza virus; D017361:Viral Nonstructural Proteins; D007372:Interferons