Disease relevance of BUNVsSgp2

• A six-way alignment of the amino acid sequences of the N and NSs proteins of viruses representing three serogroups within the Bunyavirus genus indicates regions which are strongly conserved, and provides targets for future analysis of protein function [1].
• Furthermore, NSs was found neither in virions nor in nucleocapsids isolated from infected cells [2].
• A very similar pattern was seen for cells expressing NSs from a cDNA copy by using a vaccinia virus expression system [2].
• We have now expressed the N and NSs proteins in Sf9 insect cells by using the baculovirus expression system [2].
• The NSs protein of Bunyamwera virus (Bunyaviridae) is an antiapoptotic interferon antagonist involved in silencing host protein expression by interfering with mRNA synthesis [3].

High impact information on BUNVsSgp2

• These results suggest that, although not essential for growth in tissue culture or in mice, the bunyavirus NSs protein has several functions in the virus life cycle and contributes to viral pathogenesis [4].
• Interaction of Bunyamwera Orthobunyavirus NSs Protein with Mediator Protein MED8: a Mechanism for Inhibiting the Interferon Response [3].
• An MP-12 mutant carrying a luciferase gene in place of the NSs gene replicated as efficiently as MP-12 did, produced enzymatically active luciferase during replication, and stably retained the luciferase gene after 10 virus passages, representing the first demonstration of foreign gene expression in any bunyavirus [5].
• Mutants of MP-12 partially or completely lacking the NSs open reading frame were viable [5].
• Expression of viral structural proteins from the protein expression plasmids was not required for virus rescue, whereas NSs protein expression abolished virus rescue [5].

Biological context of BUNVsSgp2

• The S RNA is 961 bases in length and, in common with other bunyaviruses, encodes two proteins, N and NSs, in overlapping reading frames [1].
• The segment is 858 nucleotides long and contains two overlapping open reading frames (ORFs), which encode the nucleocapsid (N) and nonstructural (NSs) proteins, consistent with other bunyaviruses [6].
• Here we show that a recombinant BUN that does not express NSs (BUNdelNSs) induces apoptotic cell death more rapidly than wild-type virus [7].
• These data suggest that the BUN NSs protein can delay cell death in the early stages of BUN infection by inhibiting IRF-3-mediated apoptosis [7].

Anatomical context of BUNVsSgp2

• In the latter cell line, accumulation of beta interferon mRNA occurred after infection by these NSs deletion mutants, but not after infection by MP-12 [5].
• The NSs deletion mutants formed larger plaques than MP-12 did in Vero E6 cells and failed to shut off host protein synthesis in Vero cells [5].
• The intracellular localisation of Bunyamwera virus NSs was investigated and found to be predominantly cytoplasmic, but intranuclear inclusion was also detected [8].

Associations of BUNVsSgp2 with chemical compounds

• Sucrose gradient fractionation of [35S]methionine-labeled detergent-solubilized extracts of infected BHK21 cells indicated that NSs was firmly associated with the 40S ribosomal subunit [2].
• In the absence of puromycin (or cycloheximide) full-length S vRNA, S vcRNA, and subgenomic N mRNA and putative NSs mRNA species were identified in PT virus-infected cell extracts [9].
• Here, we show that the ability to inhibit both host transcription and the interferon response is linked to interaction of NSs with the MED8 component of Mediator, a protein complex necessary for mRNA production [3].

References