Emergence of a C-terminal seven-amino-acid elongation of NS1 in around 1950 conferred a minor growth advantage to former seasonal influenza A viruses.
Influenza A viruses circulating in humans from ∼1950 to ∼1987 featured a nonstructural (NS1) protein with a C-terminal extension of seven amino acids. The biological significance of this NS1 elongation remained elusive. We observed that replication kinetics of the wild-type virus A/Hong Kong/01/68 (H3N2) and a mutant encoding a truncated NS1 were indistinguishable in most experimental systems. However, wild-type virus outcompeted the mutant during mixed infections, suggesting that the NS1 extension conferred minor growth advantages.
Institute for Virology, University Medical Center Freiburg, Freiburg, Germany.
Florens
F
Lohrmann
Ronald
R
Dijkman
Silke
S
Stertz
Volker
V
Thiel
Otto
O
Haller
Peter
P
Staeheli
Georg
G
Kochs
D019143:Evolution, Molecular; D006723:Hong Kong; D006801:Humans; D053122:Influenza A Virus, H3N2 Subtype / Q000235:genetics* / Q000302:isolation & purification / Q000502:physiology; D007251:Influenza, Human / Q000821:virology*; D016254:Mutagenesis, Insertional; D017361:Viral Nonstructural Proteins / Q000235:genetics*; D014774:Virulence; D014779:Virus Replication
C085820:INS1 protein, influenza virus; D017361:Viral Nonstructural Proteins