Role of the NSs protein in the zoonotic capacity of Orthobunyaviruses.
The family Bunyaviridae contains over 350 named isolates, classified into five genera: Orthobunyavirus, Hantavirus, Nairovirus, Phlebovirus and Tospovirus. The Orthobunyavirus genus contains some 170 isolates that are mainly transmitted by mosquitoes and are responsible for a range of disease syndromes in humans including self-limiting febrile illness, encephalitis and haemorrhagic fever. The viruses have a tripartite, negative-sense RNA genome. Analyses of viruses in four serogroups (Bunyamwera, California, Group C and Simbu) showed that the smallest (S) RNA segment encodes the nucleocapsid protein (N) and a non-structural protein called (NSs). The NSs protein of Bunyamwera virus (BUNV) has been shown to play a role in shut-off of host cell protein synthesis in mammalian cells, but no protein shut-off is observed in BUNVinfected mosquito cells (Aedes albopictus C6/36 cells). Protein shut-off in infected mammalian cells is achieved by global inhibition of RNA polymerase II-mediated transcription and enables the virus to overcome the host innate immune response. As innate defence mechanisms constitute a significant barrier to virus infection of different hosts, NSs would appear to play a key role in determining the zoonotic capacity of orthobunyaviruses.
Hart
T J
TJ
Centre for Biomolecular Sciences, University of St Andrews, Scotland, UK.
Kohl
A
A
Elliott
R M
RM
D000330:Aedes / Q000821:virology; D000818:Animals; D002044:Bunyaviridae Infections / Q000635:transmission* / Q000662:veterinary* / Q000821:virology; D006801:Humans; D019590:Nucleocapsid Proteins / Q000235:genetics / Q000502:physiology*; D016851:Orthobunyavirus / Q000472:pathogenicity*; D017361:Viral Nonstructural Proteins / Q000235:genetics / Q000502:physiology*; D015047:Zoonoses / Q000821:virology*
C423924:N protein, Bunyamwera bunyavirus; C423923:NSs protein, Bunyamwera bunyavirus; D019590:Nucleocapsid Proteins; D017361:Viral Nonstructural Proteins