Borna Disease Virus Assembles Porous Cage-like Viral Factories in the Nucleus.
Animal-derived RNA viruses frequently generate viral factories in infected cells. However, the details of how RNA viruses build such intracellular structures are poorly understood. In this study, we examined the structure and formation of the viral factories, called viral speckle of transcripts (vSPOTs), that are produced in the nuclei of host cells by Borna disease virus (BDV). Super-resolution microscopic analysis showed that BDV assembled vSPOTs as intranuclear cage-like structures with 59-180-nm pores. The viral nucleoprotein formed the exoskeletons of vSPOTs, whereas the other viral proteins appeared to be mainly localized within these structures. In addition, stochastic optical reconstruction microscopy revealed that filamentous structures resembling viral ribonucleoprotein complexes (RNPs) appeared to protrude from the outer surfaces of the vSPOTs. We also found that vSPOTs disintegrated into RNPs concurrently with the breakdown of the nuclear envelope during mitosis. These observations demonstrated that BDV generates viral replication factories whose shape and formation are regulated, suggesting the mechanism of the integrity of RNA virus persistent infection in the nucleus.
From the Department of Biology, Osaka Dental University, Hirakata 573-1121.|the Department of Virus Research, Institute for Frontier Life and Medical Sciences (InFRONT).
Yuya
Y
Hirai
the Graduate School of Frontier Biosciences, Osaka University, Suita 565-0871, and.
Yasuhiro
Y
Hirano
the Graduate School of Frontier Biosciences, Osaka University, Suita 565-0871, and.|the Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology, Kobe 651-2492, Japan.
Atsushi
A
Matsuda
the Graduate School of Frontier Biosciences, Osaka University, Suita 565-0871, and.|the Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology, Kobe 651-2492, Japan.
Yasushi
Y
Hiraoka
the Department of Virus Research, Institute for Frontier Life and Medical Sciences (InFRONT).
Tomoyuki
T
Honda
the Department of Virus Research, Institute for Frontier Life and Medical Sciences (InFRONT), tomonaga@virus.kyoto-u.ac.jp.|Departments of Molecular Virology, Graduate School of Medicine, and.|Mammalian Regulatory Network, Graduate School of Biostudies, Kyoto University, Kyoto 606-8507.
Keizo
K
Tomonaga
D000818:Animals; D001891:Borna disease virus / Q000378:metabolism*; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism* / Q000821:virology; D009698:Nucleoproteins / Q000378:metabolism*; D014764:Viral Proteins / Q000378:metabolism*
D009698:Nucleoproteins; D014764:Viral Proteins
chromosomes; microscopy; negative-strand RNA virus; nucleus; ribonuclear protein (RNP)