Mapping the Landscape of the Lymphocytic Choriomeningitis Virus Stable Signal Peptide Reveals Novel Functional Domains

Saunders, April A.; Ting, Joey; Meisner, Jeffrey; Neuman, Benjamin W.; Perez, Mar; Torre, Juan Carlos de la; Buchmeier, Michael J.

doi:10.1128/jvi.02759-06

Cited by 54 publications

(96 citation statements)

References 30 publications

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Section: Discussionsupporting

confidence: 81%

“…Our results correlate well with prior studies of other arenaviruses, such as JUNV and LCMV (8). The K33 residue has been shown to play an essential role in GPC fusion by interacting with GP2 to prime the complex for pHinduced membrane fusion (8,22,23). The F49 residue is located within the recently identified FILL sorting signal motif that is required for glycoprotein processing and surface expression (8,24).…”

Section: Discussionsupporting

confidence: 80%

“…Our data are consistent with previous studies, which have demonstrated that K33A, F49A, and C57A lead to a nearly complete loss of fusogenic activity of JUNV GPC (22,24,25). K33 has been shown to play a critical role in mediating membrane fusion (8,22,23). As F49A and C57A are defective in GPC processing (Fig.…”

Section: Effects Of Ssp Mutations On Gpc Expression and Processingsupporting

confidence: 82%

“…Many of these residues have been characterized previously in the context of GPC expression and pseudotyped viruses (8,11,(22)(23)(24)(25)(26)(27)(28); however, their biological roles have not been investigated. Here, we show that multiple SSP conserved residues are essential or critical for viral infection of cell culture and/or guinea pigs by participating in the membrane fusion reaction, and that two residues, N37 and R55, are required for viral virulence by a yet-to-be-determined mechanism.…”

mentioning

confidence: 99%

“…The 58-amino-acid (aa) conserved SSP contains an N-terminal G2 myristoylation site, two hydrophobic domains (h1 and h2) separated by an ectodomain, and a C-terminal SP cleavage site (Fig. 1A) (8), although the exact boundaries of these domains have not been well defined (9,10). SSP is an essential component of the envelope glycoprotein complex and plays important roles not only in regulating the intracellular trafficking and proteolytic maturation of GPC but also in the pH-induced membrane fusion reaction (11,12).…”

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confidence: 99%

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Characterization of the Glycoprotein Stable Signal Peptide in Mediating Pichinde Virus Replication and Virulence

Shao

et al. 2016

J Virol

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Arenaviruses can cause lethal hemorrhagic fevers in humans with few preventative and therapeutic measures. The arenaviral glycoprotein stable signal peptide (SSP) is unique among signal peptides in that it is an integral component of the mature glycoprotein complex (GPC) and plays important roles not only in GPC expression and processing but also in the membrane fusion process during viral entry. Using the Pichinde virus (PICV) reverse genetics system, we analyzed the effects of alanine substitutions at many conserved residues within the SSP on viral replication in cell culture and in a guinea pig infection model. Our data showed that the K33A, F49A, and C57A mutations abolished GPC-mediated cell entry and therefore could not allow for the generation of viable recombinant viruses, demonstrating that these residues are essential for the PICV life cycle. The G2A mutation caused a marked reduction of cell entry at the membrane fusion step, and while this mutant virus was viable, it was significantly attenuated in vitro and in vivo. The N20A mutation also reduced membrane fusion activity and viral virulence in guinea pigs, but it did not significantly affect cell entry or viral growth in cell culture. Two other mutations (N37A and R55A) did not affect membrane fusion or viral growth in vitro but significantly reduced viral virulence in vivo. Taken together, our data suggest that the GPC SSP plays an essential role in mediating viral entry and also contributes to viral virulence in vivo. IMPORTANCESeveral arenaviruses, such as Lassa fever virus, can cause severe and lethal hemorrhagic fever diseases with high mortality and morbidity, and no FDA-approved vaccines or therapies are currently available. Viral entry into cells is mediated by arenavirus GPC that consists of an SSP, the receptor-binding GP1, and transmembrane GP2 protein subunits. Using a reverse genetics system of a prototypic arenavirus, Pichinde virus (PICV), we have shown for the first time in the context of virus infections of cell culture and of guinea pigs that the SSP plays an essential role in mediating the membrane fusion step as well as in other yet-to-be-determined processes during viral infection. Our study provides important insights into the biological roles of GPC SSP and implicates it as a good target for the development of antivirals against deadly human arenavirus pathogens.A renaviruses can cause neurologic or hemorrhagic fever diseases in humans, and few preventive or therapeutic measures are available (1, 2). The most significant arenavirus pathogen is Lassa fever virus (LASV), which causes infections that are endemic to many countries in West Africa, with an estimated 500,000 cases resulting in ϳ5,000 deaths annually (3). Except for Junin virus (JUNV), which has a vaccine, Candid#1, used only in Argentina, no licensed vaccine for human use is currently available for any other arenaviruses. Therapeutic options are limited and depend mainly on supportive care. Ribavirin, a nonspecific antiviral compound, has shown some efficacy ...

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Section: Discussionsupporting

confidence: 81%

Section: Discussionsupporting

confidence: 80%

Section: Effects Of Ssp Mutations On Gpc Expression and Processingsupporting

confidence: 82%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Characterization of the Glycoprotein Stable Signal Peptide in Mediating Pichinde Virus Replication and Virulence

Shao

et al. 2016

J Virol

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Arenavirus Quasispecies and Their Biological Implications

Grande-Pérez

Martı́n

Moreno

et al. 2015

Current Topics in Microbiology and Immunology

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The family Arenaviridae currently comprises over 20 viral species, each of them associated with a main rodent species as the natural reservoir and in one case possibly phyllostomid bats. Moreover, recent findings have documented a divergent group of arenaviruses in captive alethinophidian snakes. Human infections occur through mucosal exposure to aerosols or by direct contact of abraded skin with infectious materials. Arenaviruses merit interest both as highly tractable experimental model systems to study acute and persistent infections and as clinically important human pathogens including Lassa (LASV) and Junin (JUNV) viruses, the causative agents of Lassa and Argentine hemorrhagic fevers (AHFs), respectively, for which there are no FDA-licensed vaccines, and current therapy is limited to an off-label use of ribavirin (Rib) that has significant limitations. Arenaviruses are enveloped viruses with a bi-segmented negative strand (NS) RNA genome. Each genome segment, L (ca 7.3 kb) and S (ca 3.5 kb), uses an ambisense coding strategy to direct the synthesis of two polypeptides in opposite orientation, separated by a noncoding intergenic region (IGR). The S genomic RNA encodes the virus nucleoprotein (NP) and the precursor (GPC) of the virus surface glycoprotein that mediates virus receptor recognition and cell entry via endocytosis. The L genome RNA encodes the viral RNA-dependent RNA polymerase (RdRp, or L polymerase) and the small (ca 11 kDa) RING finger protein Z that has functions of a bona fide matrix protein including directing virus budding. Arenaviruses were thought to be relatively stable genetically with intra- and interspecies amino acid sequence identities of 90-95 % and 44-63 %, respectively. However, recent evidence has documented extensive arenavirus genetic variability in the field. Moreover, dramatic phenotypic differences have been documented among closely related LCMV isolates. These data provide strong evidence of viral quasispecies involvement in arenavirus adaptability and pathogenesis. Here, we will review several aspects of the molecular biology of arenaviruses, phylogeny and evolution, and quasispecies dynamics of arenavirus populations for a better understanding of arenavirus pathogenesis, as well as for the development of novel antiviral strategies to combat arenavirus infections.

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