Disease relevance of NSs

• Bunyamwera bunyavirus nonstructural protein NSs is a nonessential gene product that contributes to viral pathogenesis [1].
• The smallest RNA segment, S, encodes the nucleocapsid protein N and a nonstructural protein, NSs, in overlapping reading frames [1].
• In addition, the abrogation of NSs expression changed Bunyamwera virus from a noninducer to an inducer of an interferon-beta promoter [1].
• We have recently identified the nonstructural protein NSs of Bunyamwera virus (BUNV), the prototype of the family Bunyaviridae, as a virulence factor that blocks the induction of IFN by dsRNA [2].

High impact information on NSs

• We have generated a mutant virus lacking NSs, called BUNdelNSs, by reverse genetics [1].
• Here, we demonstrate that NSs targets the RNA polymerase II (RNAP II) complex [3].
• However, NSs prevented CTD phosphorylation at serine 2, suggesting a block in transition from initiation to elongation [3].
• 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 [4].
• In agreement with previously published data concerning CAL serogroup viruses, the nucleocapsid (N) and non-structural (NSs) proteins were encoded in over-lapping open reading frames (ORFs) [5].

Biological context of NSs

• The NSs ORFs were either 279 or 294 nucleotides in length, which would encode 92 or 97 amino-acid proteins, respectively [5].

References