Fig. 8

Finch creek virus sequencing and in vitro analysis. a Sequence annotation of FCV L, M and S polypeptides based on predictions of protein domains and cleavage sites. Numbers on the figure indicate relevant amino acid positions. OTU-like, ovarian tumor family-like domain. RdRp, RNA dependent RNA polymerase domain. Transmembrane domains (TM) are indicated by dark grey boxes. S, signal peptide. Signal peptidase cleavage sites for the Pre-Gn (VGA₃₄EN) and Pre-Gc (VSS₇₃₃LS) proteins are indicated by cleavage site sequence and bold solid line. Subtilisin kexin isozyme-1 (SKI-1) cleavage sites (RRLL, RKPL) are indicated by dashed lines. The number of predicted O-linked glycosylation sites in the mucin-like domain is indicated above the domain (O = number of sites). Green: Gn protein. Magenta: Gc protein. Predicted N- and O-linked glycans in the Gn and Gc proteins are indicated by Y or *, respectively. N, nucleocapsid protein. b SDS-PAGE of purified FCV virions. Presumed protein identities are indicated by arrows. Identities confirmed by mass spectrometry are denoted with *. c Western blot analysis of anti-FCV serum against lysate of FCV-infected (lane 1) or mock-infected (lane 2) cells. d Reactivity of anti-FCV mouse serum to FCV or TAGV-infected BSR cells in fixed cell ELISA. Values graphed represent average optical density (OD) reading at 405 nm after subtraction of mock-OD. Dotted line indicates the threshold of detection which is equal to 2 × the average OD value of mock-infected cells. e Growth kinetics of FCV in ISE6 and BSR cells. Viral titres in supernatants from three replicate wells were determined by TCID₅₀ method after titration on BSR cells