Fig. 4

FIV Vif requires C-terminal FcaA3Z2 (A3Z2b) residues for A3 degradation. a Scheme of A3Z2/A3C chimeras (Z2C1, -C4, -C5, -C30). Highlighted are C-terminal sequence differences between FcaA3Z2 and HsaA3C. b 293T cells were co-transfected with expression plasmids for Z2C1, Z2C4, Z2C5 or Z2C30 and FIV Vif, HIV-1 or SIVmac Vif. A3s contain a C-terminal HA-tag; Vifs contain a C-terminal V5-tag. The expression of chimeras and Vif proteins were detected by using anti-HA and anti-V5 antibodies, respectively. Cell lysates were also analyzed for equal amounts of total proteins using the anti-tubulin antibody. c Expression plasmids for A3C, FcaA3Z2, and big cat A3Z2s were co-transfected with FIV Vif into 293T cells. 48 h later, cells were analyzed by immunoblot. The expression of A3 and Vif proteins were detected by using anti-HA and anti-V5 antibodies, respectively. FcaA3s represent domestic cat (Felis catus); Pti, Ple, and Lly represent Panthera tigris corbetti; Panthera leo bleyenberghi; Lynx lynx, varI, variant I. d Amino acid logo for the C-terminus in 17 A3Z2 sequences from 12 Carnivores species (upper panel) and for 51 A3Z2 sequences from 17 Primates species (lower panel). Residues identified to evolve under purifying or diversifying selection are respectively labelled with “pur” (black) or with “div” (red)