Hierarchy among viral RNA (vRNA) segments in their role in vRNA incorporation into influenza A virions.
The genome of influenza A viruses comprises eight negative-strand RNA segments. Although all eight segments must be present in cells for efficient viral replication, the mechanism(s) by which these viral RNA (vRNA) segments are incorporated into virions is not fully understood. We recently found that sequences at both ends of the coding regions of the HA, NA, and NS vRNA segments of A/WSN/33 play important roles in the incorporation of these vRNAs into virions. In order to similarly identify the regions of the PB2, PB1, and PA vRNAs of this strain that are critical for their incorporation, we generated a series of mutant vRNAs that possessed the green fluorescent protein gene flanked by portions of the coding and noncoding regions of the respective segments. For all three polymerase segments, deletions at the ends of their coding regions decreased their virion incorporation efficiencies. More importantly, these regions not only affected the incorporation of the segment in which they reside, but were also important for the incorporation of other segments. This effect was most prominent with the PB2 vRNA. These findings suggest a hierarchy among vRNA segments for virion incorporation and may imply intersegment association of vRNAs during virus assembly.
Laboratory of Microbiology, Department of Disease Control, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Japan.
Yukiko
Y
Muramoto
Ayato
A
Takada
Ken
K
Fujii
Takeshi
T
Noda
Kiyoko
K
Iwatsuki-Horimoto
Shinji
S
Watanabe
Taisuke
T
Horimoto
Hiroshi
H
Kida
Yoshihiro
Y
Kawaoka
D000818:Animals; D002460:Cell Line; D004285:Dogs; D005822:Genetic Vectors; D049452:Green Fluorescent Proteins / Q000032:analysis / Q000235:genetics; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype / Q000235:genetics / Q000502:physiology*; D010957:Plasmids; D012367:RNA, Viral / Q000235:genetics / Q000378:metabolism*; D012324:RNA-Dependent RNA Polymerase / Q000235:genetics; D017384:Sequence Deletion; D014764:Viral Proteins / Q000235:genetics; D014771:Virion / Q000378:metabolism*; D019065:Virus Assembly / Q000235:genetics / Q000502:physiology*
C061290:PA protein, influenza viruses; C502893:PB2 protein, influenza virus; D012367:RNA, Viral; D014764:Viral Proteins; C077346:influenza virus polymerase basic protein 1; D049452:Green Fluorescent Proteins; D012324:RNA-Dependent RNA Polymerase