Figure 7. IRG-tandem proteins interact with virulence factors.
(A) Loading of Irgb2-b1CIM on to vacuoles of RH variants in IFNγ-induced CIM DDC. Irgb2-b1CIM loading (dot plots, upper image) is positively correlated with ROP5 expression level in the parasite (western blot, lower image). (B) Autoradiogram (33P) of immunoprecipitated IRG proteins in DDC infected with T. gondii. Irga6 was phosphorylated (open arrow head) by virulence factors of T. gondii in BL/6 DDC, but not in CIM DDC. Irgb-tandem proteins were phosphorylated only in CIM DDC (filled arrow head) in a ROP5/ROP18-dependent manner. UIC = uninfected control. Asterisk (*) indicates non-specific phosphorylated proteins (C) Ribbon model of Irgb2 predicted based on the structure of Irga6, showing diversifying selection associated with H4 and αD of the G-domain. The colours of the ribbons are based on the π and πa/πs values among 40 alleles sequenced from mouse strains and wild mice with a 120 bp slide window and 10 bp step. The colours indicate the πa/πs value, from purifying selection (blue) to significantly diversifying selection (red). The saturations of colours are defined by overall π value in the sliding window, indicate conserved regions of the protein (low saturation) to highly polymorphic regions (high saturation).