Disease relevance of SNVsSgp1

• Using several complementary in vitro assays we find that the bunyavirus nucleocapsid protein (N) is an RNA chaperone [1].
• The S RNA of PUU90-13 is 1847 nt in length and contains the nucleocapsid (N) protein gene and a potential overlapping open reading frame (ORF-2) previously described in other hantaviruses [2].
• The dissociation constant, K(d), for the interaction of the Hantaan virus (HTNV) N protein and its genomic S segment (vRNA) was measured under several solution conditions [3].
• The K(d) values for HTNV and Sin Nombre virus N proteins were nearly identical for the S segment open reading frame RNA, showing weak affinity over several binding reaction conditions [3].
• Cross-protection against challenge with Puumala virus after immunization with nucleocapsid proteins from different hantaviruses [4].

High impact information on SNVsSgp1

• Viral N antigen first began to appear in heart, lung, liver, spleen, and/or kidney by 7 d, whereas viral RNA was present in those tissues as well as in thymus, salivary gland, intestine, white fat, and brown fat [5].
• The nucleocapsid (N) proteins of hantaviruses such as the Sin Nombre virus (SNV) bind to membranes and viral RNAs, associate with transcription and replication complexes, and oligomerize during the process of virus assembly [6].
• In contrast, the assembly of Sin Nombre virus N protein-HTNV vRNA complexes was inhibited by the presence of Mg(2+) or an increase in the ionic strength [3].
• They are enveloped negative-strand RNA viruses with a tripartite genome encoding the nucleocapsid (N) protein, the two surface glycoproteins Gn and Gc, and an RNA-dependent RNA polymerase [7].
• The N protein is the most abundant component of the virion; it encapsidates genomic RNA segments forming ribonucleoproteins and participates in genome transcription and replication as well as virus assembly [7].

Chemical compound and disease context of SNVsSgp1

• The NP of Seoul virus in which the tryptophan at amino acid number 119 was replaced by alanine (W119A mutation) did not multimerize in the yeast two-hybrid assay, indicating that tryptophan 119 in region 1 is important for the NP-NP interaction in yeast [8].
• A newly identified hantavirus, tentatively called Four Corners virus (FCV), was found to be the aetiological agent of a 1993 outbreak of hantavirus pulmonary syndrome (HPS) in the southwestern United States. Immunodominant epitopes of 43 and 31 amino acids were identified in the nucleocapsid protein and G1 glycoprotein, respectively [9].
• Genes encoding the nucleocapsid (N) proteins of two hantaviruses, Hantaan virus strain 76-118 (HTN) and Puumala virus strain CG 18-20 (PUU), were expressed in Escherichia coli as histidine-tagged proteins [10].
• The recombinant protein was produced by cloning and expressing the nucleocapsid encoding gene of PUU as a polyhistidine fusion protein in Escherichia coli [11].

Biological context of SNVsSgp1

• The bunyavirus nucleocapsid protein is an RNA chaperone: possible roles in viral RNA panhandle formation and genome replication [1].
• Statistical analysis of the third base substitution frequency in the N ORFs of PUU90-13 and other PUU viruses suggests that the ORF-2 is functional [2].
• The specificity of virus neutralization appears to reside in the HTN glycoproteins, since a vaccinia virus recombinant expressing the HTN nucleocapsid protein was unable to elicit a neutralizing antibody response [12].
• Sequence alignments made from several hantavirus N protein sequences showed that the region identified has a 58% identity and an 86% similarity among these amino acid sequences [13].
• Neutralizing monoclonal antibodies (MAbs) against the G1 and G2 envelope GPs inhibited cell fusion, whereas nonneutralizing MAbs against G1 or G2 and MAbs against the nucleocapsid protein (NP) did not [14].

Anatomical context of SNVsSgp1

• These data suggest that infection with Hantaan virus results in the generation of CTL to limited epitopes on the nucleocapsid protein and that infection also results in the generation of cross-reactive T-cell responses to distantly related hantaviruses which cause the distinct hantavirus pulmonary syndrome [15].
• All CD8(+) cytotoxic T-lymphocyte (CTL) lines recognized one of two epitopes on the nucleocapsid protein: one epitope spanning amino acids 12 to 20 and the other spanning amino acids 421 to 429 [15].
• Moreover, the association of the N protein with actin microfilaments was confirmed by coimmunoprecipitation with beta-actin-specific antibody [16].
• We established both CD4(+) and CD8(+) N-specific cell lines from two donors and CD4(+) G1-specific cell lines from a third donor [15].
• Transfected Vero E6 cells that expressed GPs but not those that expressed NP fused and formed syncytia [14].

Associations of SNVsSgp1 with chemical compounds

• Both PUU90-13 and PUUBerkel lack a potential N-linked glycosylation site found on the G2 glycoprotein of other PUU viruses [2].
• However, the HTNV N protein showed an enhanced specificity for HTNV vRNA as compared with the S segment open reading frame RNA or a nonviral RNA with increasing ionic strength and the presence of Mg(2+) [3].
• Further mapping of the interaction regions by alanine scanning indicated the importance of basic amino acids along the N protein and especially asparagine-394, histidine-395, and phenyalanine-396 in forming the binding interface [17].
• These results show that ReoPro can lower viral loads and that ribavirin and HIP, but not anti-N antibody, inhibit seroconversion and reduce viral loads in a dose-dependent manner [18].
• The recombinant N protein (bac-PUU-N) was solubilized with 6 M urea, dialyzed, and purified by anion-exchange liquid chromatography [19].

Other interactions of SNVsSgp1

• Analyses of complete nucleocapsid protein and glycoprotein precursor sequences indicated that the isolates are strains of a novel hantavirus (proposed name "Maporal") which is phylogenetically most closely related to the viruses known to cause hantavirus pulmonary syndrome in southern South America [20].

Analytical, diagnostic and therapeutic context of SNVsSgp1

• Recombinant virus purified from the original variant was able to grow to the same titers in cell culture and showed the same characteristic immunofluorescence pattern when stained for the nucleocapsid protein [21].
• Similarly, the truncated NP of Seoul virus expressing amino acids 155 to 429 showed a homologous interaction in a competitive ELISA but not in the yeast two-hybrid assay, indicating that the C-terminal region is important for the multimerization detected by competitive ELISA [8].
• Analysis of truncated mutants in the mammalian two-hybrid assay showed that N-terminal amino acids 1 to 43 are involved in and C-terminal amino acids 393 to 398 (VNHFHL) are absolutely crucial for the homotypic interactions [17].
• Double immunofluorescence staining of BCCV-infected Vero cells with anti-BCCV nucleocapsid (N) monoclonal antibody and phalloidin revealed a colocalization of the BCCV N protein with actin microfilaments [16].
• According to sequencing data for the genomic RNA S segment and nucleocapsid protein and data obtained by immunoblotting with a panel of monoclonal antibodies, the virus, designated Tula virus, is a distinct novel member of the genus Hantavirus [22].

References