Fig. 1. Genomic organization of FCoV. Genomic ORFs are shown as boxes. Only pp1ab is shown as a translation product of the genomic RNA. The non-structural proteins nsp1–11 are translated from ORF1a (dark grey shading) and translation of the ORF1b proteins (nsp12–16) occurs following −1 ribosomal frameshifting (RFS). The nsp11 protein is not depicted as it represents a short (9 aa) carboxyl extension of nsp10. nsp9, ssRNA-binding protein (ssRBP); nsp12, RNA-dependent RNA polymerase (RdRp); nsp13, helicase (Hel) and NTPase; nsp14, 3′→5′ exoribonuclease (ExoN) and N7-methyltransferase (N7-MT); nsp15, uridylate-specific endonuclease (NendoU); nsp16, 2′-O-methyltransferase (2′-OMT).
