title: Involvement of actin microfilaments in the replication of human parainfluenza virus type 3.
abstract: Several studies indicate that paramyxoviruses require a specific cellular factor(s) for transcription of their genomic RNAs. We previously reported that the cellular cytoskeletal protein actin, in its polymeric form, participates in the transcription of human parainfluenza virus type 3 (HPIV3) in vitro. In the present study, we investigated the role of the polymeric form of actin, i.e., the actin microfilaments of the cytoskeletal framework, in the reproduction of HPIV3 in vivo. Pulse-chase labeling analyses indicate that the viral nucleocapsid-associated proteins, NP and P, are present predominantly in the cytoskeletal framework during infection. By in situ hybridization, we found that viral mRNAs and genomic RNA were synthesized from the nucleocapsids that were bound to the cytoskeletal framework. Double immunofluorescent labeling and confocal microscopy of the cytoarchitecture revealed that the viral nucleocapsids are specifically localized on the actin microfilaments. Treatment of cells with the actin-depolymerizing agent, cytochalasin D, resulted in the inhibition of viral RNA synthesis and ribonucleoprotein accumulation. These results strongly suggest that actin microfilaments play an important role in the replication of HPIV3.
authors.affiliation: Molecular Virology Graduate Program, Department of Biochemistry, Case Western Reserve University, Cleveland, Ohio 44106, USA.
authors.forename: S
authors.initials: S
authors.lastname: Gupta
authors.forename: B P
authors.initials: BP
authors.lastname: De
authors.forename: J A
authors.initials: JA
authors.lastname: Drazba
authors.forename: A K
authors.initials: AK
authors.lastname: Banerjee
mesh_terms: D008841:Actin Cytoskeleton / Q000378:metabolism*; D000199:Actins / Q000378:metabolism*; D000818:Animals; D002460:Cell Line; D002522:Chlorocebus aethiops; D015638:Cytochalasin D / Q000494:pharmacology; D003599:Cytoskeleton / Q000378:metabolism; D006801:Humans; D007424:Intracellular Fluid; D019384:Nucleic Acid Synthesis Inhibitors / Q000494:pharmacology; D010224:Parainfluenza Virus 3, Human / Q000235:genetics / Q000254:growth & development / Q000378:metabolism / Q000502:physiology*; D012367:RNA, Viral / Q000378:metabolism; D012261:Ribonucleoproteins / Q000378:metabolism; D014771:Virion; D014779:Virus Replication
chemical_list: D000199:Actins; D019384:Nucleic Acid Synthesis Inhibitors; D012367:RNA, Viral; D012261:Ribonucleoproteins; D015638:Cytochalasin D