Infectious Bursal Disease Virus: Ribonucleoprotein Complexes of a Double-Stranded RNA Virus

Luque, Daniel; Saugar, Irene; Rejas, María Teresa; Carrascosa, José L.; Rodrı́guez, José F.; Castón, José R.

doi:10.1016/j.jmb.2008.11.029

Cited by 86 publications

(90 citation statements)

References 43 publications

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“…6B), allowing translation of the GLV proteins and packaging into nascent, progeny GLV virions. This strategy for transcription inside the icosahedral capsid is thought to be common to all dsRNA viruses except possibly birnaviruses (67), which lack the "Tϭ2" capsid organization (68). The only solvent-accessible channels that span the GLV capsid appear to occur at each of the 12 5-fold axes, and though somewhat narrow (ca.…”

Section: Discussionmentioning

confidence: 99%

Three-Dimensional Structure of a Protozoal Double-Stranded RNA Virus That Infects the Enteric Pathogen Giardia lamblia

Janssen

Takagi

Parent

et al. 2015

J Virol

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Giardia lamblia virus (GLV) is a small, nonenveloped, nonsegmented double-stranded RNA (dsRNA) virus infecting Giardia lamblia, the most common protozoan pathogen of the human intestine and a major agent of waterborne diarrheal disease worldwide. GLV (genus Giardiavirus) is a member of family Totiviridae, along with several other groups of protozoal or fungal viruses, including Leishmania RNA viruses and Trichomonas vaginalis viruses. Interestingly, GLV is more closely related than other Totiviridae members to a group of recently discovered metazoan viruses that includes penaeid shrimp infectious myonecrosis virus (IMNV). Moreover, GLV is the only known protozoal dsRNA virus that can transmit efficiently by extracellular means, also like IMNV. In this study, we used transmission electron cryomicroscopy and icosahedral image reconstruction to examine the GLV virion at an estimated resolution of 6.0 Å. Its outermost diameter is 485 Å, making it the largest totivirus capsid analyzed to date. Structural comparisons of GLV and other totiviruses highlighted a related "T‫"2؍‬ capsid organization and a conserved helix-rich fold in the capsid subunits. In agreement with its unique capacity as a protozoal dsRNA virus to survive and transmit through extracellular environments, GLV was found to be more thermoresistant than Trichomonas vaginalis virus 1, but no specific protein machinery to mediate cell entry, such as the fiber complexes in IMNV, could be localized. These and other structural and biochemical findings provide a basis for future work to dissect the cell entry mechanism of GLV into a "primitive" (early-branching) eukaryotic host and an important enteric pathogen of humans. IMPORTANCENumerous pathogenic bacteria, including Corynebacterium diphtheriae, Salmonella enterica, and Vibrio cholerae, are infected with lysogenic bacteriophages that contribute significantly to bacterial virulence. In line with this phenomenon, several pathogenic protozoa, including Giardia lamblia, Leishmania species, and Trichomonas vaginalis are persistently infected with dsRNA viruses, and growing evidence indicates that at least some of these protozoal viruses can likewise enhance the pathogenicity of their hosts. Understanding of these protozoal viruses, however, lags far behind that of many bacteriophages. Here, we investigated the dsRNA virus that infects the widespread enteric parasite Giardia lamblia. Using electron cryomicroscopy and icosahedral image reconstruction, we determined the virion structure of Giardia lamblia virus, obtaining new information relating to its assembly, stability, functions in cell entry and transcription, and similarities and differences with other dsRNA viruses. The results of our study set the stage for further mechanistic work on the roles of these viruses in protozoal virulence. Giardia lamblia (also called G. intestinalis or duodenalis) is a flagellated, parasitic protozoan and an important cause of diarrheal disease worldwide, especially in developing countries. It is a member of the super...

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Section: Discussionmentioning

confidence: 99%

Three-Dimensional Structure of a Protozoal Double-Stranded RNA Virus That Infects the Enteric Pathogen Giardia lamblia

Janssen

Takagi

Parent

et al. 2015

J Virol

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“…Segment A (3.3 kb) has two partially overlapping open reading frames. Open reading frame A-1 encodes a polyprotein that is autocatalytically cleaved to yield the immature outer capsid protein pVP2, the viral protease VP4 and the ribonucleoprotein VP3 (Sánchez & Rodriguez, 1999;Lejal et al, 2000;Da Costa et al, 2002;Luque et al, 2009). The pVP2 protein is further processed to yield the mature VP2, the immunodominant antigen of IBDV (Fahey et al, 1991).…”

Section: Introductionmentioning

confidence: 99%

Genetic characterization of South American infectious bursal disease virus reveals the existence of a distinct worldwide-spread genetic lineage

et al. 2015

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Infectious bursal disease virus (IBDV) is one of the most concerning health problems for world poultry production. IBDVs comprise four well-defined evolutionary lineages known as classic (c), classic attenuated (ca), variant (va) and very virulent (vv) strains. Here, we characterized IBDVs from South America by the genetic analysis of both segments of the viral genome. Viruses belonging to c, ca and vv strains were unambiguously classified by the presence of molecular markers and phylogenetic analysis of the hypervariable region of the vp2 gene. Notably, the majority of the characterized viruses (9 out of 15) could not be accurately assigned to any of the previously described strains and were then denoted as distinct (d) IBDVs. These dIBDVs constitute an independent evolutionary lineage that also comprises field IBDVs from America, Europe and Asia. The hypervariable VP2 sequence of dIBDVs has a unique and conserved molecular signature (272T, 289P, 290I and 296F) that is a diagnostic character for classification. A discriminant analysis of principal components (DAPC) also identified the dIBDVs as a cluster of genetically related viruses separated from the typical strains. DAPC and genetic distance estimation indicated that the dIBDVs are one of the most genetically divergent IBDV lineages. The vp1 gene of the dIBDVs has non-vvIBDV markers and unique nucleotide and amino acid features that support their divergence in both genomic segments. The present study suggests that the dIBDVs comprise a neglected, highly divergent lineage that has been circulating in world poultry production since the early time of IBDV emergence.

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“…Members of the families Birnaviridae are exceptions to the rule that all dsRNA viruses have a Tϭ1 core made of 60 dimers of the CP; birnaviruses have a single Tϭ13 shell (16,59) that surrounds a polyploid dsRNA genome (41) organized as a ribonucleoprotein complex (42).…”

mentioning

confidence: 99%

The T=1 Capsid Protein of Penicillium chrysogenum Virus Is Formed by a Repeated Helix-Rich Core Indicative of Gene Duplication

Luque

González

Garriga

et al. 2010

J Virol

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Penicillium chrysogenum virus (PcV), a member of the Chrysoviridae family, is a double-stranded RNA (dsRNA) fungal virus with a multipartite genome, with each RNA molecule encapsidated in a separate particle. Chrysoviruses lack an extracellular route and are transmitted during sporogenesis and cell fusion. The PcV capsid, based on a T‫1؍‬ lattice containing 60 subunits of the 982-amino-acid capsid protein, remains structurally undisturbed throughout the viral cycle, participates in genome metabolism, and isolates the virus genome from host defense mechanisms. Using three-dimensional cryoelectron microscopy, we determined the structure of the PcV virion at 8.0 Å resolution. The capsid protein has a high content of rod-like densities characteristic of ␣-helices, forming a repeated ␣-helical core indicative of gene duplication. Whereas the PcV capsid protein has two motifs with the same fold, most dsRNA virus capsid subunits consist of dimers of a single protein with similar folds. The spatial arrangement of the ␣-helical core resembles that found in the capsid protein of the L-A virus, a fungal totivirus with an undivided genome, suggesting a conserved basic fold. The encapsidated genome is organized in concentric shells; whereas the inner dsRNA shells are well defined, the outermost layer is dense due to numerous interactions with the inner capsid surface, specifically, six interacting areas per monomer. The outermost genome layer is arranged in an icosahedral cage, sufficiently well ordered to allow for modeling of an A-form dsRNA. The genome ordering might constitute a framework for dsRNA transcription at the capsid interior and/or have a structural role for capsid stability.Viruses with double-stranded RNA (dsRNA) genomes are found in a broad range of organisms, ranging from bacteria to simple (fungi and protozoa) and complex (animals and plants) eukaryotes.

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Infectious Bursal Disease Virus: Ribonucleoprotein Complexes of a Double-Stranded RNA Virus

Cited by 86 publications

References 43 publications

Three-Dimensional Structure of a Protozoal Double-Stranded RNA Virus That Infects the Enteric Pathogen Giardia lamblia

Three-Dimensional Structure of a Protozoal Double-Stranded RNA Virus That Infects the Enteric Pathogen Giardia lamblia

Genetic characterization of South American infectious bursal disease virus reveals the existence of a distinct worldwide-spread genetic lineage

The T=1 Capsid Protein of Penicillium chrysogenum Virus Is Formed by a Repeated Helix-Rich Core Indicative of Gene Duplication

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