title: Role of the CM2 protein in the influenza C virus replication cycle.
abstract: CM2 is the second membrane protein of influenza C virus. Although its biochemical characteristics, coding strategy, and properties as an ion channel have been extensively studied, the role(s) of CM2 in the virus replication cycle remains to be clarified. In order to elucidate this role, in the present study we generated CM2-deficient influenza C virus-like particles (VLPs) and examined the VLP-producing 293T cells, VLPs, and VLP-infected HMV-II cells. Quantification of viral RNA (vRNA) in the VLPs by real-time PCR revealed that the CM2-deficient VLPs contain approximately one-third of the vRNA found in wild-type VLPs although no significant differences were detected in the expression levels of viral components in VLP-producing cells or in the number and morphology of the generated VLPs. This finding suggests that CM2 is involved in the genome packaging process into VLPs. Furthermore, HMV-II cells infected with CM2-deficient VLPs exhibited significantly reduced reporter gene expression. Although CM2-deficient VLPs could be internalized into HMV-II cells as efficiently as wild-type VLPs, a smaller amount of vRNA was detected in the nuclear fraction of CM2-deficient VLP-infected cells than in that of wild-type VLP-infected cells, suggesting that the uncoating process of the CM2-deficient VLPs in the infected cells did not proceed in an appropriate manner. Taken together, the data obtained in the present study indicate that CM2 has a potential role in the genome packaging and uncoating processes of the virus replication cycle.
authors.affiliation: Department of Infectious Diseases, Yamagata University Faculty of Medicine, 2-2-2 Iida-Nishi, Yamagata 990-9585, Japan.
authors.forename: Takatoshi
authors.initials: T
authors.lastname: Furukawa
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Muraki
authors.forename: Takeshi
authors.initials: T
authors.lastname: Noda
authors.forename: Emi
authors.initials: E
authors.lastname: Takashita
authors.forename: Ri
authors.initials: R
authors.lastname: Sho
authors.forename: Kanetsu
authors.initials: K
authors.lastname: Sugawara
authors.forename: Yoko
authors.initials: Y
authors.lastname: Matsuzaki
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Shimotai
authors.forename: Seiji
authors.initials: S
authors.lastname: Hongo
mesh_terms: D002460:Cell Line; D055786:Gene Knockout Techniques; D006801:Humans; D009982:Gammainfluenzavirus / Q000235:genetics / Q000502:physiology*; D012367:RNA, Viral / Q000032:analysis / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014763:Viral Matrix Proteins / Q000172:deficiency / Q000502:physiology*; D022701:Virosomes; D019065:Virus Assembly; D057646:Virus Uncoating
chemical_list: C090877:CM2 protein, Influenza C virus; D012367:RNA, Viral; D014763:Viral Matrix Proteins; D022701:Virosomes