Measles virus assembly within membrane rafts.
During measles virus (MV) replication, approximately half of the internal M and N proteins, together with envelope H and F glycoproteins, are selectively enriched in microdomains rich in cholesterol and sphingolipids called membrane rafts. Rafts isolated from MV-infected cells after cold Triton X-100 solubilization and flotation in a sucrose gradient contain all MV components and are infectious. Furthermore, the H and F glycoproteins from released virus are also partly in membrane rafts (S. N. Manié et al., J. Virol. 74:305-311, 2000). When expressed alone, the M but not N protein shows a low partitioning (around 10%) into rafts; this distribution is unchanged when all of the internal proteins, M, N, P, and L, are coexpressed. After infection with MGV, a chimeric MV where both H and F proteins have been replaced by vesicular stomatitis virus G protein, both the M and N proteins were found enriched in membrane rafts, whereas the G protein was not. These data suggest that assembly of internal MV proteins into rafts requires the presence of the MV genome. The F but not H glycoprotein has the intrinsic ability to be localized in rafts. When coexpressed with F, the H glycoprotein is dragged into the rafts. This is not observed following coexpression of either the M or N protein. We propose a model for MV assembly into membrane rafts where the virus envelope and the ribonucleoparticle colocalize and associate.
Vincent
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Immunité & Infections Virales, VPV, CNRS-UCBL UMR 5537, Faculté de Médecine Lyon RTH Laennec, 69372 Lyon Cedex 08, France.
Gerlier
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Manié
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D006367:HeLa Cells; D006389:Hemagglutinins, Viral / Q000378:metabolism; D006801:Humans; D008459:Measles virus / Q000502:physiology*; D021962:Membrane Microdomains / Q000378:metabolism / Q000821:virology*; D008954:Models, Biological; D012261:Ribonucleoproteins / Q000378:metabolism; D014760:Viral Fusion Proteins / Q000378:metabolism; D014764:Viral Proteins / Q000378:metabolism*; D019065:Virus Assembly
D006389:Hemagglutinins, Viral; D012261:Ribonucleoproteins; D014760:Viral Fusion Proteins; D014764:Viral Proteins; C032397:hemagglutinin protein G, measles virus