Comparative analysis of the ability of the polymerase complexes of influenza viruses type A, B and C to assemble into functional RNPs that allow expression and replication of heterotypic model RNA templates in vivo.
Influenza viruses type A, B, and C are human pathogens that share common structural and functional features, yet they do not form natural reassortants. To determine to what extent type-specific interactions of the polymerase complex with template RNA contribute to this lack of genotypic mixing, we investigated whether homotypic or heterotypic polymerase complexes support the expression and replication of model type A, B, or C RNA templates in vivo. A plasmid-based expression system, as initially described by Pleschka et al. [(1996) J. Virol. 70, 4188-4192] for influenza A virus, was developed for influenza viruses B/Harbin/7/94 and C/Johannesburg/1/66. The type A core proteins expressed heterotypic model RNAs with similar efficiencies as the homotypic RNA. The influenza B virus model RNA was efficiently expressed by all three types of polymerase complexes. Although no functional polymerase complex could be reconstituted with heterotypic P protein subunits, when the influenza A virus P proteins were expressed together with heterotypic nucleoproteins, significant, albeit limited, expression of RNA templates of all influenza virus types was detected. Taken together, our results suggest that less strict type-specific interactions are involved for the polymerase complex of influenza A compared with influenza B or C viruses.
Crescenzo-Chaigne
B
B
Unité de Génétique Moléculaire des Virus Respiratoires, URA 1966 CNRS, Institut Pasteur, Paris, France.
Naffakh
N
N
van der Werf
S
S
D000818:Animals; D001483:Base Sequence; D019556:COS Cells; D003001:Cloning, Molecular; D004279:DNA, Viral; D012321:DNA-Directed RNA Polymerases / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression; D006801:Humans; D009980:Influenza A virus / Q000235:genetics*; D009981:Influenza B virus / Q000235:genetics*; D009982:Gammainfluenzavirus / Q000235:genetics*; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D019590:Nucleocapsid Proteins; D009698:Nucleoproteins; D012367:RNA, Viral / Q000096:biosynthesis* / Q000737:chemistry; D012324:RNA-Dependent RNA Polymerase / Q000235:genetics / Q000378:metabolism; D012261:Ribonucleoproteins / Q000235:genetics / Q000378:metabolism*; D013698:Templates, Genetic; D014158:Transcription, Genetic; D014758:Viral Core Proteins / Q000235:genetics / Q000378:metabolism*; D014764:Viral Proteins / Q000235:genetics / Q000378:metabolism; D014779:Virus Replication
D004279:DNA, Viral; D019590:Nucleocapsid Proteins; D009698:Nucleoproteins; C061290:PA protein, influenza viruses; C057027:PB2 protein, Influenzavirus A; D012367:RNA, Viral; D012261:Ribonucleoproteins; D014758:Viral Core Proteins; D014764:Viral Proteins; C077346:influenza virus polymerase basic protein 1; D012324:RNA-Dependent RNA Polymerase; D012321:DNA-Directed RNA Polymerases