Structure of Double-Shelled Rice Dwarf Virus

Lu, Guangying; Zhou, Z.H.; Baker, Matthew L.; Jakana, Joanita; Cai, Deyou; Wei, Xincheng; Chen, Shengxiang; Gu, Xiaocheng; Chiu, Wah

doi:10.1128/jvi.72.11.8541-8549.1998

Cited by 56 publications

(16 citation statements)

References 48 publications

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“…insert). This sort of inner capsid architecture is also seen in other segmented dsRNA viruses including the orbiviruses bluetongue (Grimes et al, 1998) and Broadhaven viruses (Schoehn et al, 1997), orthoreovirus (Dryden et al, 1998), the phytoreovirus rice dwarf virus (Lu et al, 1998), aquareovirus (Shaw et al, 1996), cypovirus (Hill et al, 1999;Zhang et al, 1999), the fungal totiviruses L-A and P4 (Cheng et al, 1994;CastSn et al, 1997), and cystovirus q~6 (Butcher et al, 1997). This organization of protein subunits in the inner capsid layer appears to be a consistent trend among many segmented dsRNA viruses and indeed may be important in defining the architecture of the viral core.…”

Section: Scaffoldingmentioning

confidence: 70%

“…Electron cryomicroscopy has also been used extensively to study other common viruses having dsRNA genomes, including bluetongue virus (Prasad et al, 1992;Hewat et al, 1992;Grimes et al, 1997) and Broadhaven virus (Schoehn et al, 1997) of the genus orbivirus, mammalian orthoreovirus (Dryden et al, 1993;Dryden et al, 1998), insect cypovirus (Hill et al, 1999;Zhang et al, 1999), aquareovirus (Shaw et al, 1996), rice dwarf virus of the genus phytoreovirus (Lu et al, 1998), cystovirus ~06 (Butcher et al, 1997), infectious bursal disease virus of the family Birnaviridae (BSttcher et al, 1997), and L-A virus of the family Totiviridae (Cheng et al, 1994;CastSn et al, 1997). These studies have served to highlight the common structural themes arising across multiple genera of dsRNA viruses and also to highlight important architectural differences, which, among dsRNA viruses with segmented genomes, are typically seen within the vicinity of the icosahedral 5-fold axes.…”

Section: Other Viruses With Dsrna Genomesmentioning

confidence: 99%

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Mechanism of genome transcription in segmented dsRNA viruses

Lawton

Estes

Prasad

2000

Advances in Virus Research

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Genome transcription is a critical stage in the life cycle of a virus, as this is the process by which the viral genetic information is presented to the host cell protein synthesis machinery for the production of the viral proteins needed for genome replication and progeny virion assembly. Viruses with dsRNA genomes face a particular challenge in that host cells do not produce proteins which can transcribe from a dsRNA template. Therefore, dsRNA viruses contain all of the necessary enzymatic machinery to synthesize complete mRNA transcripts within the core without the need for disassembly. Indeed one of the more striking observations about genome transcription in dsRNA viruses is that this process occurs efficiently only when the transcriptionally competent particle is fully intact. This observation suggests that all of the components of the TCP, including the viral genome, the transcription enzymes, and the viral capsid, function together to produce and release mRNA transcripts and that each component has a specific and critical role to play in promoting the efficiency of this process. This review has examined the process of genome transcription in dsRNA viruses from the perspective of rotavirus as a model system. However, despite numerous architectural and organizational differences among the families of dsRNA viruses, numerous studies suggest that the basic mechanism of mRNA production may be similar in most, if not all, viruses having dsRNA genomes. Important functional similarities include (1) the presence of a capsid-bound RNA-dependent RNA polymerase, which produces single-stranded mRNA transcripts from the dsRNA genome and regenerates the dsRNA genome from single-stranded RNA templates; (2) in viruses infecting eukaryotic hosts, the presence of all the enzymatic activities needed to generate the 5' cap required by the eukaryotic translation machinery; (3) the high degree of structural order present in the packaged genome, suggesting the requirement for organization in the viral core; (4) the role of the innermost capsid protein as a scaffold on which the core components of the transcription apparatus are assembled; and (5) the release of nascent mRNA transcripts through channels at the icosahedral vertices. The process of genome transcription in dsRNA viruses will become better understood as structural studies progress to higher resolution and as more viruses become amenable to study using site-directed mutagenesis coupled with viral reconstitution to generate recombinant particles having precise functional and structural changes. Future studies will dissect important intermolecular interactions required for efficient mRNA synthesis and will shed further light on the reasons for which the viral core must be structurally intact in order for transcription to occur efficiently. Structural studies of the capping enzymes at atomic resolution will reveal how multiple enzyme activities reside within a single polypeptide and how they act in concert to synthesize the 5' cap on the end of each mature transcript. Pe...

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Section: Scaffoldingmentioning

confidence: 70%

Section: Other Viruses With Dsrna Genomesmentioning

confidence: 99%

Mechanism of genome transcription in segmented dsRNA viruses

Lawton

Estes

Prasad

2000

Advances in Virus Research

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“…(23,143) were docked into the outer capsid density of the RDV cryoreconstruction and revealed a better fit of the HEX structure. This and a sequence comparison between the RDV and BTV P8 and VP7 proteins, respectively, led to a proposal that P8 may have an upper domain with a ␤-sandwich motif and a lower domain of ␣ helices (207).…”

Section: Fig 31 Model Of Transcription In L-a Virusmentioning

confidence: 99%

Adding the Third Dimension to Virus Life Cycles: Three-Dimensional Reconstruction of Icosahedral Viruses from Cryo-Electron Micrographs

Baker

Olson

Fuller

1999

Microbiol Mol Biol Rev

473

268

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SUMMARY Viruses are cellular parasites. The linkage between viral and host functions makes the study of a viral life cycle an important key to cellular functions. A deeper understanding of many aspects of viral life cycles has emerged from coordinated molecular and structural studies carried out with a wide range of viral pathogens. Structural studies of viruses by means of cryo-electron microscopy and three-dimensional image reconstruction methods have grown explosively in the last decade. Here we review the use of cryo-electron microscopy for the determination of the structures of a number of icosahedral viruses. These studies span more than 20 virus families. Representative examples illustrate the use of moderate- to low-resolution (7- to 35-Å) structural analyses to illuminate functional aspects of viral life cycles including host recognition, viral attachment, entry, genome release, viral transcription, translation, proassembly, maturation, release, and transmission, as well as mechanisms of host defense. The success of cryo-electron microscopy in combination with three-dimensional image reconstruction for icosahedral viruses provides a firm foundation for future explorations of more-complex viral pathogens, including the vast number that are nonspherical or nonsymmetrical.

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“…When examined by negative-stain electron microscopy, CPV appears as a single-shelled icosahedron, with a diameter of 600 Å and 12 characteristic turret-like spikes. This organization contrasts with the double-shelled (e.g., rice dwarf virus [19]) or triple-shelled (e.g., animal reovirus [4], rotavirus [22], bluetongue virus [13]) arrangements which are typical for viruses in the Reoviridae. The full, infectious CPV capsid resembles that of other reoviruses functionally since it contains an RNA-dependent RNA polymerase and is fully capable of RNA transcription (17).…”

mentioning

confidence: 78%

Visualization of Protein-RNA Interactions in Cytoplasmic Polyhedrosis Virus

Zhang

et al. 1999

J Virol

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Unlike the multiple-shelled organization of otherReoviridae members, cytoplasmic polyhedrosis virus (CPV) has a single-shelled capsid. The three-dimensional structures of full and empty CPV by electron cryomicroscopy show identical outer shells but differ inside. The outer surface reveals a T=1 icosahedral shell decorated with spikes at its icosahedral vertices. The internal space of the empty CPV is unoccupied except for 12 mushroom-shaped densities attributed to the transcriptional enzyme complexes. The ordered double-stranded RNA inside the full capsid forms spherical shells spaced 25 Å apart. The RNA-protein interactions suggest a mechanism for RNA transcription and release.

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Structure of Double-Shelled Rice Dwarf Virus

Cited by 56 publications

References 48 publications

Mechanism of genome transcription in segmented dsRNA viruses

Mechanism of genome transcription in segmented dsRNA viruses

Adding the Third Dimension to Virus Life Cycles: Three-Dimensional Reconstruction of Icosahedral Viruses from Cryo-Electron Micrographs

Visualization of Protein-RNA Interactions in Cytoplasmic Polyhedrosis Virus

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