Influenza A Virus Hemagglutinin is Required for the Assembly of Viral Components Including Bundled vRNPs at the Lipid Raft.
The influenza glycoproteins, hemagglutinin (HA) and neuraminidase (NA), which are associated with the lipid raft, have the potential to initiate virion budding. However, the role of these viral proteins in infectious virion assembly is still unclear. In addition, it is not known how the viral ribonucleoprotein complex (vRNP) is tethered to the budding site. Here, we show that HA is necessary for the efficient progeny virion production and vRNP packaging in the virion. We also found that the level of HA does not affect the bundling of the eight vRNP segments, despite reduced virion production. Detergent solubilization and a subsequent membrane flotation analysis indicated that the accumulation of nucleoprotein, viral polymerases, NA, and matrix protein 1 (M1) in the lipid raft fraction was delayed without HA. Based on our results, we inferred that HA plays a role in the accumulation of viral components, including bundled vRNPs, at the lipid raft.
Laboratory of Virology, Institute of Microbial Chemistry (BIKAKEN), 3-14-23 Kamiosaki, Shinagawa-ku, Tokyo 141-0021, Japan. takizawan@bikaken.or.jp.
Naoki
N
Takizawa
Kitasato Institute for Life Sciences and Graduate School for Infection Control, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8641, Japan. fmomose@lisci.kitasato-u.ac.jp.
Fumitaka
F
Momose
Kitasato Institute for Life Sciences and Graduate School for Infection Control, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8641, Japan. morikawa@lisci.kitasato-u.ac.jp.
Yuko
Y
Morikawa
Laboratory of Virology, Institute of Microbial Chemistry (BIKAKEN), 3-14-23 Kamiosaki, Shinagawa-ku, Tokyo 141-0021, Japan. anomoto@bikaken.or.jp.
Akio
A
Nomoto
D019267:Hemagglutinin Glycoproteins, Influenza Virus / Q000378:metabolism*; D009980:Influenza A virus / Q000502:physiology*; D021962:Membrane Microdomains / Q000821:virology*; D009698:Nucleoproteins / Q000378:metabolism*; D056224:Viral Structures / Q000378:metabolism*; D019065:Virus Assembly
D019267:Hemagglutinin Glycoproteins, Influenza Virus; D009698:Nucleoproteins
hemagglutinin; influenza virus; lipid raft; viral genome packaging; virus budding