Manawatu virus: a nodavirus isolated from Costelytra zealandica (White) (Coleoptera: Scarabaeidae)

Scotti, Paul D.; Fredericksen, Susan

doi:10.1007/bf01310736

Cited by 46 publications

(61 citation statements)

References 11 publications

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“…The range of insect hosts for FHV is not well studied. FHV replicates in the larvae of the wax moth, Galleria mellonella, and in cultured Drosophila melanogaster cells (Scotti et al, 1983) in the laboratory. FHV has not shown any cytopathic effect (CPE) in mammalian cells and is not considered a human pathogen.…”

Section: Introductionmentioning

confidence: 99%

Flock house virus replicates and expresses green fluorescent protein in mosquitoes

Dasgupta

Cheng

Bartholomay

et al. 2003

Journal of General Virology

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Flock house virus (FHV) is a non-enveloped, positive-sense RNA virus of insect origin that belongs to the family Nodaviridae. FHV has been shown to overcome the kingdom barrier and to replicate in plants, insects, yeast and mammalian cells. Although of insect origin, FHV has not previously been shown to replicate in mosquitoes. We have tested FHV replication in vitro in C6/36 cells (derived from neonatal Aedes albopictus) and in vivo in four different genera of mosquitoes, Aedes, Culex, Anopheles and Armigeres. FHV replicated to high titres in C6/36 cells that had been subcloned to support maximum growth of FHV. When adult mosquitoes were orally fed or injected with the virus, FHV antigen was detected in various tissues and infectious virus was recovered. Vectors developed from an infectious cDNA clone of a defective-interfering RNA, derived from FHV genomic RNA2, expressed green fluorescent protein in Drosophila cells and adult mosquitoes. This demonstrates the potential of FHV-based vectors for expression of foreign genes in mosquitoes and possibly other insects.

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Section: Introductionmentioning

confidence: 99%

Flock house virus replicates and expresses green fluorescent protein in mosquitoes

Dasgupta

Cheng

Bartholomay

et al. 2003

Journal of General Virology

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“…FHV contains one of the smallest known genomes of any animal RNA virus (4). The 4.5-kb genome is bipartite, with two capped but nonpolyadenylated RNA segments copackaged into a 29-nm nonenveloped icosahedral capsid (47). The larger 3.1-kb RNA species (RNA1) encodes protein A, the FHV RNA-dependent RNA polymerase (RdRp) (4).…”

mentioning

confidence: 99%

The Cellular Chaperone Heat Shock Protein 90 Facilitates Flock House Virus RNA Replication in Drosophila Cells

Kampmueller¹,

Miller

2005

J Virol

108

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The assembly of viral RNA replication complexes on intracellular membranes represents a critical step in the life cycle of positive-strand RNA viruses. We investigated the role of the cellular chaperone heat shock protein 90 (Hsp90) in viral RNA replication complex assembly and function using Flock House virus (FHV), an alphanodavirus whose RNA-dependent RNA polymerase, protein A, is essential for viral RNA replication complex assembly on mitochondrial outer membranes. The Hsp90 chaperone complex transports cellular mitochondrial proteins to the outer mitochondrial membrane import receptors, and thus we hypothesized that Hsp90 may also facilitate FHV RNA replication complex assembly or function. Treatment of FHV-infected Drosophila S2 cells with the Hsp90-specific inhibitor geldanamycin or radicicol potently suppressed the production of infectious virions and the accumulation of protein A and genomic, subgenomic, and template viral RNA. In contrast, geldanamycin did not inhibit the activity of preformed FHV RNA replication complexes. Hsp90 inhibitors also suppressed viral RNA and protein A accumulation in S2 cells expressing an FHV RNA replicon. Furthermore, Hsp90 inhibition with either geldanamycin or RNAi-mediated chaperone downregulation suppressed protein A accumulation in the absence of viral RNA replication. These results identify Hsp90 as a host factor involved in FHV RNA replication and suggest that FHV uses established cellular chaperone pathways to assemble its RNA replication complexes on intracellular membranes.

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“…Flock house virus (FHV), a member of the Nodaviridae family, is a nonenveloped, icosahedral insect virus whose genome consists of two positive-strand RNA molecules (3,28). The bipartite nature of the FHV genome organizes its nonstructural and structural genes onto RNA1 (3.1 kb) and RNA2 (1.4 kb),…”

mentioning

confidence: 99%

Capsid Protein Synthesis from Replicating RNA Directs Specific Packaging of the Genome of a Multipartite, Positive-Strand RNA Virus

Venter

Krishna

Schneemann

2005

J Virol

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Flock house virus (FHV) is a bipartite, positive-strand RNA insect virus that encapsidates its two genomic RNAs in a single virion. It provides a convenient model system for studying the principles underlying the copackaging of multipartite viral RNA genomes. In this study, we used a baculovirus expression system to determine if the uncoupling of viral protein synthesis from RNA replication affected the packaging of FHV RNAs. We found that neither RNA1 (which encodes the viral replicase) nor RNA2 (which encodes the capsid protein) were packaged efficiently when capsid protein was supplied in trans from nonreplicating RNA. However, capsid protein synthesized in cis from replicating RNA2 packaged RNA2 efficiently in the presence and absence of RNA1. These results demonstrated that capsid protein translation from replicating RNA2 is required for specific packaging of the FHV genome. This type of coupling between genome replication and translation and RNA packaging has not been observed previously. We hypothesize that RNA2 replication and translation must be spatially coordinated in FHV-infected cells to facilitate retrieval of the viral RNAs for encapsidation by newly synthesized capsid protein. Spatial coordination of RNA and capsid protein synthesis may be key to specific genome packaging and assembly in other RNA viruses.Flock house virus (FHV), a member of the Nodaviridae family, is a nonenveloped, icosahedral insect virus whose genome consists of two positive-strand RNA molecules (3, 28). The bipartite nature of the FHV genome organizes its nonstructural and structural genes onto RNA1 (3.1 kb) and RNA2 (1.4 kb),respectively. An open reading frame (ORF) that nearly spans the length of RNA1 encodes protein A (112 kDa), the RNAdependent RNA polymerase which directs the replication of RNA1, RNA2, and a 387-nucleotide (nt) subgenomic RNA3 (7). RNA3 corresponds to the 3Ј end of RNA1 and encodes two small proteins, B1 and B2 (10). No function has been ascribed to B1, while B2 functions as an inhibitor of RNA silencing (15). Interestingly, RNA3 is also required as a transactivator of RNA2 replication, but the mechanism by which this is achieved is not completely understood (6). RNA2 encodes the 43-kDa capsid precursor protein ␣, which is the only structural protein required for the assembly of FHV provirions (7, 9). Each provirion consists of 180 subunits of protein ␣, arranged with Tϭ3 quasiequivalent symmetry, and the two genomic RNAs. Provirions are not infectious and undergo an autocatalytic maturation process in which protein ␣ cleaves into proteins ␤ (38 kDa) and ␥ (5 kDa). Both cleavage products remain associated with the matured, infectious virion (9, 26).FHV RNA1 and RNA2 are packaged into a single virion but the mechanism by which FHV copackages its multipartite genome is still unknown (14). One hypothesis is that an interaction between RNA1 and RNA2 occurs prior to packaging, allowing the genome to be encapsidated as a complex. The absence of significant complementarity between RNA1 and RNA2, however, does ...

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Manawatu virus: a nodavirus isolated from Costelytra zealandica (White) (Coleoptera: Scarabaeidae)

Cited by 46 publications

References 11 publications

Flock house virus replicates and expresses green fluorescent protein in mosquitoes

Flock house virus replicates and expresses green fluorescent protein in mosquitoes

The Cellular Chaperone Heat Shock Protein 90 Facilitates Flock House Virus RNA Replication in Drosophila Cells

Capsid Protein Synthesis from Replicating RNA Directs Specific Packaging of the Genome of a Multipartite, Positive-Strand RNA Virus

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