Naturally Occurring Polymorphisms of the Mouse Gammaretrovirus Receptors CAT-1 and XPR1 Alter Virus Tropism and Pathogenicity

Figure 5

Predicted topology and sequence variation of the XPR1 receptor for XP-MLVs. At the top is shown the predicted structure with eight putative transmembrane domains and 4 extracellular loops (ECLs). The center diagram shows the relative locations of the 4 ECLs in the XPR1 protein, and the bottom shows sequence variation in the two ECLs involved in virus entry. Sequence is provided for the 5 functional XPR1 variants in Mus, and the red arrows indicate the 6 residues involved in entry.