FIG. 6.

Domain structure of the HTLV-2 Rex protein. The functional domains or regions of the 170-amino-acid Rex protein based on this study and alignment with HTLV-1 Rex are indicated. RNA binding domain-NLS, aa 1 to 19. Core activation effector-NES domain, aa 81 to 94. Multimerization domains, aa 57 to 71 and 124 to 132. In Rex-2, the region spanning residues 144 to 164 is important for efficient function and includes key phosphorylation sites (Ser151 and -153). Mutations in this region also impair nuclear-to-cytoplasmic cycling.