Nuclear retention of M1 protein in a temperature-sensitive mutant of influenza (A/WSN/33) virus does not affect nuclear export of viral ribonucleoproteins.
We investigated the properties of ts51, an influenza virus (A/WSN/33) temperature-sensitive RNA segment 7 mutant. Nucleotide sequence analysis revealed that ts51 possesses a single nucleotide mutation, T-261----C, in RNA segment 7, resulting in a single amino acid change. Phenylalanine (position 79) in the wild-type M1 protein was substituted by serine in ts51. This mutation was phenotypically characterized by dramatic nuclear accumulation of the M1 protein and interfered with some steps at the late stage of virus replication, possibly affecting the assembly and/or budding of viral particles. However, although M1 protein was retained within the nucleus, export of the newly synthesized viral ribonucleoprotein containing the minus-strand RNA into the cytoplasm was essentially the same at both permissive and nonpermissive temperatures. The roles of M1 in the export of viral ribonucleoproteins from the nucleus into the cytoplasm and in the virus particle assembly process are discussed.
Rey
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Department of Microbiology and Immunology, Jonsson Comprehensive Cancer Center, University of California at Los Angeles School of Medicine 90024-1747.
Nayak
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D000818:Animals; D001692:Biological Transport; D015152:Blotting, Northern; D015153:Blotting, Western; D002417:Cattle; D002467:Cell Nucleus / Q000378:metabolism*; D002478:Cells, Cultured; D004591:Electrophoresis, Polyacrylamide Gel; D005455:Fluorescent Antibody Technique; D005814:Genes, Viral; D006358:Hot Temperature; D009980:Influenza A virus / Q000235:genetics* / Q000502:physiology; D019590:Nucleocapsid Proteins; D009698:Nucleoproteins; D012367:RNA, Viral / Q000032:analysis; D012261:Ribonucleoproteins / Q000378:metabolism*; D014758:Viral Core Proteins / Q000378:metabolism; D014763:Viral Matrix Proteins / Q000378:metabolism*; D014771:Virion; D014779:Virus Replication
C031540:M-protein, influenza virus; C488936:M1 protein, Influenza A virus; D019590:Nucleocapsid Proteins; D009698:Nucleoproteins; D012367:RNA, Viral; D012261:Ribonucleoproteins; D014758:Viral Core Proteins; D014763:Viral Matrix Proteins