Figure 5. Characterisation of intracellular IFN receptors.

(A) Phylogenetic tree analysis of identified trout IFN receptors with known homologues in vertebrates, as determined by the Neighbour-Joining method. The bootstrap values of the tree nodes are indicated as percentages. (B) Schematic illustrating the modes for generation of iIFNR transcript variants. Trout membrane bound and intracellular IFNAR1 are transcribed from two distinct genes whilst membrane bound and intracellular IFNAR2 are generated by alternative splicing of an RNA transcript derived from the same gene. (C) Protein structural domains of human and trout IFNAR1 and IFNAR2 receptors. (D, E) Confirmation that intracellular IFNR proteins are produced in RTG-2 cells. RTG-2 cells were transfected with pTurbo-iIFNR1-GFP or pTurbo-iIFNR2-GFP and analysed by Western blot analysis using a polyclonal antibody against GFP.