Fine Structure Analysis of Pichinde Virus Nucleocapsids

Young, Paul R.; Howard, C. R.

doi:10.1099/0022-1317-64-4-833

Cited by 69 publications

(54 citation statements)

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“…The phlebovirus RNPs have some of the smallest N proteins and represent the extreme of asymmetry among a range of architectures displayed by RNPs of negative-sense viruses. The arenaviruses also have an asymmetric RNP (4,12), but the N protein is unrelated to the phlebovirus N and has an additional exoribonuclease domain (20,21). The RNP architecture is understood in greatest detail for those viruses with RNP of highest symmetry.…”

Section: Discussionmentioning

confidence: 99%

Phleboviruses encapsidate their genomes by sequestering RNA bases

Raymond¹,

Piper

Gerrard

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

102

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Rift Valley fever and Toscana viruses are human pathogens for which no effective therapeutics exist. These and other phleboviruses have segmented negative-sense RNA genomes that are sequestered by a nucleocapsid protein (N) to form ribonucleoprotein (RNP) complexes of irregular, asymmetric structure, previously uncharacterized at high resolution. N binds nonspecifically to single-stranded RNA with nanomolar affinity. Crystal structures of Rift Valley fever virus N-RNA complexes reconstituted with defined RNAs of different length capture tetrameric, pentameric and hexameric N-RNA multimers. All N-N subunit contacts are mediated by a highly flexible α-helical arm. Arm movement gives rise to the three multimers in the crystal structures and also explains the asymmetric architecture of the RNP. Despite the flexible association of subunits, the crystal structures reveal an invariant, monomeric RNP building block, consisting of the core of one N subunit, the arm of a neighboring N, and four RNA nucleotides with the flanking phosphates. Up to three additional RNA nucleotides bind between subunits. The monomeric building block is matched in size to the repeating unit in viral RNP, as visualized by electron microscopy. N sequesters four RNA bases in a narrow hydrophobic binding slot and has polar contacts only with the sugar-phosphate backbone, which faces the solvent. All RNA bases, whether in the binding slot or in the subunit interface, face the protein in a manner that is incompatible with base pairing or with "reading" by the viral polymerase. transmitted by arthropod vectors and cause a variety of severe diseases worldwide. The Rift Valley fever virus is a highly infectious, mosquito-borne pathogen endemic to sub-Saharan Africa. RVFV infects livestock and humans and generally causes a flu-like illness; however, 1% of cases result in hemorrhagic fever disease, which has a 50% case-fatality rate (1). The closely related Toscana virus (TOSV) is endemic to the Mediterranean basin, is transmitted by infected phlebotomine sandflies and causes neurological dysfunction in humans (2). The membrane envelope of bunyaviruses encloses a three-segment, negative-sense RNA genome that is encapsidated by a nucleocapsid protein (N), forming the ribonucleoprotein (RNP) (3). However, the size and sequence of N vary extensively among the five genera of the Bunyaviridae family. Phlebovirus N are highly similar, but they appear unrelated to N of the other four bunyavirus genera.We showed previously that phleboviruses have a unique genome-packaging strategy and an RNP that lacks the helical symmetry observed in some other negative-sense RNA viruses (NSVs) (4, 5). However, the detailed interactions between phlebovirus N and the viral RNA genome are unknown. The crystal structure of a RVFV N monomer revealed a compact helical fold with two lobes (5). The structure of an RVFV N hexamer demonstrated conformational flexibility in N and showed a putative RNA binding site on the inner surface of the hexameric ring (6). An α-helical arm, which is...

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Section: Discussionmentioning

confidence: 99%

Phleboviruses encapsidate their genomes by sequestering RNA bases

Raymond¹,

Piper

Gerrard

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

102

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“…The two nucleocapsids are beaded, loosely helical structures (9-15 nm in diameter). They each form a closed smaller (400-600 nm) or larger (1000-1300 nm) circle depending on whether they contain the S or L RNA, respectively (Young and Howard, 1983). Virions are frequently genetically diploid.…”

Section: Viral Genome Organizationmentioning

confidence: 99%

Diseases of the central nervous system caused by lymphocytic choriomeningitis virus and other arenaviruses

Wilson¹,

Peters²

2014

Neurovirology

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“…S2), indicating that the majority of r3LCMV CAT/GFP infectious virions contained both (GPC-GFP and CAT-NP) S segments. There are some precedents based on both genetics (9) and structural (10,31) analysis in support of S polyploidy within arenavirus infectious particles. Our data showed that preparations of infectious particles from LCMV WT and r3LCMV were undistinguishable either by size or shape, but we were unable to determine precisely the percentage of particles with two or three segments present within the r3LCMV population.…”

Section: Bhk-21 Cells (Ifn -mentioning

confidence: 99%

Generation of recombinant lymphocytic choriomeningitis viruses with trisegmented genomes stably expressing two additional genes of interest

Emonet

Garidou

McGavern

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

124

216

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Several arenaviruses cause hemorrhagic fever disease in humans for which no licensed vaccines are available and current therapeutic intervention is limited to the off-label use of the wide-spectrum antiviral ribavirin. However, the prototypic arenavirus lymphocytic choriomeningitis virus (LCMV) has proven to be a Rosetta stone for the investigation of virus-host interactions. Arenaviruses have a bisegmented negative-strand RNA genome. The S segment encodes for the virus nucleoprotein and glycoprotein, whereas the L segment encodes for the virus polymerase (L) and Z protein. The ability to generate recombinant LCMV (rLCMV) expressing additional foreign genes of interest would open novel avenues for the study of virushost interactions and the development of novel vaccine strategies and high-throughput screens to identify antiarenaviral molecules. To this end, we have developed a trisegmented (1L ؉ 2S) rLCMV-based approach (r3LCMV). Each of the two S segments in r3LCMV was altered to replace one of the viral genes by a gene of interest. All r3LCMVs examined expressing different reported genes were stable both genetically and phenotypically and exhibited wild-type growth properties in cultured cells. Reporter gene expression in r3LCMV-infected cells provided an accurate surrogate of levels of virus multiplication. Notably, some r3LCMVs displayed highly attenuated virulence in mice but induced protective immunity against a subsequent lethal challenge with wild-type LCMV, supporting the potential development of r3LCMV-based vaccines.antiviral screen ͉ reverse genetic ͉ viral attenuation A renaviruses merit significant interest both as tractable experimental model systems to study acute and persistent viral infections and as clinically important human pathogens (1-3). Thus, the prototypic arenavirus lymphocytic choriomeningitis virus (LCMV) has proven to be a superb workhorse in the field of virology and immunology (1). However, several arenaviruses cause hemorrhagic fever (HF) disease in humans, associated with high morbidity and mortality (2, 3). The Old World arenavirus Lassa virus (LASV) poses the highest public health concern among HF arenaviruses. LASV is estimated to infect several hundred thousand individuals yearly in its endemic region of West Africa, resulting in a high number of Lassa fever disease cases (2). Likewise, several New World arenaviruses, chiefly Junin virus, cause viral HF disease (3). Moreover, evidence indicates that the worldwide distributed LCMV is a neglected human pathogen of clinical significance (4) and poses a special threat to immunocompromised individuals (5, 6).Public health concerns posed by human pathogenic arenaviruses are aggravated by the lack of licensed vaccines and current therapy being limited to the use of the nucleoside analog ribavirin (Rib) that can cause significant side effects and requires an early and i.v. administration for optimal efficacy (3). Therefore, it is important to develop novel effective antiarenaviral drugs and vaccines, tasks that would be facilitated ...

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Fine Structure Analysis of Pichinde Virus Nucleocapsids

Cited by 69 publications

References 0 publications

Phleboviruses encapsidate their genomes by sequestering RNA bases

Phleboviruses encapsidate their genomes by sequestering RNA bases

Diseases of the central nervous system caused by lymphocytic choriomeningitis virus and other arenaviruses

Generation of recombinant lymphocytic choriomeningitis viruses with trisegmented genomes stably expressing two additional genes of interest

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