Fig. 14.12

Genome organization of flaviviruses. (a) Yellow fever virus, vaccine strain 17D. (b) TBE virus, strain Neudörfl. (c) Hepatitis C virus. (d) Bovine viral diarrhoea virus (BVDV), strain SD-1 (non-cytopathogenic). In hepatitis C virus and pestiviruses (BVDV), an IRES is located in the 5′ UTR. In members of the genus Flavivirus (yellow fever virus and TBE virus), the 5′ end of the genome is modified by a cap group. The genomes of flaviviruses have a continuous open reading frame. It encodes a polyprotein that is proteolytically cleaved into the different protein components (structural proteins in colour). Responsible for this process are enzymes which are a constitutive part of the polyprotein and autocatalytically activate themselves, as well as cellular proteases and signalases. The numbers refer to the amino acid positions in the polyprotein at which the cleavages occur