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Publication Abstract from PubMed

Viruses from the family Dicistroviridae can cause substantial economic damage by infecting agriculturally important insects. Israeli acute bee paralysis virus (IAPV) causes honeybee colony collapse disorder in the United States. High-resolution molecular details of the genome delivery mechanism of dicistroviruses are unknown. Here we present a cryo-EM analysis of IAPV virions induced to release their genomes in vitro We determined structures of full IAPV virions primed to release their genomes to a resolution of 3.3 A and of empty capsids to a resolution of 3.9 A. We show that IAPV does not form expanded A particles before the genome release, as is the case in the related enteroviruses from the family Picornaviridae The structural changes observed in the empty IAPV particles include the detachment of the VP4 minor capsid proteins from the inner face of the capsid and partial loss of the structure of the N-terminal arms of the VP2 capsid proteins. Unlike in many picornaviruses, the empty particles of IAPV are not expanded, relative to the native virions, and do not contain pores in their capsids that might serve as channels for the genome release. Therefore, re-arrangement of a unique region of the capsid is probably required for IAPV genome release. IMPORTANCE: Honeybee populations in Europe and North America are declining due to pressure from pathogens including viruses. Israeli acute bee paralysis virus from the family Dicistroviridae causes honeybee colony collapse disorder in the United States. The delivery of virus genomes into host cells is necessary for the initiation of infection. Here we present structural cryo-electron microscopy analysis of IAPV particles induced to release their genomes. We show that the genome release is not preceded by an expansion of IAPV virions, as is the case in the related picornaviruses that infect vertebrates. Furthermore, minor capsid proteins detach from the capsid upon the genome release. The genome leaves behind empty particles that have compact protein shells.

Cryo-EM study of genome release of dicistrovirus Israeli acute bee paralysis virus.,Mullapudi E, Fuzik T, Pridal A, Plevka P J Virol. 2016 Dec 7. pii: JVI.02060-16. PMID:27928006^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.