Figure 1

Functional domains of HTLV-1 Rex and efficient expression and detection of affinity-tagged Rex-1. (A) The functional domains of the 189 aa Rex-1 are depicted in shaded boxes. The nuclear localization signal (NLS) and the RNA binding domain (RBD) are positioned within the first 19 amino acids of the protein. The activation domain and the nuclear export signal (NES) are located between residues 79-99. This region is flanked by the two multimerization domains; the first lies between amino acids 57-66, whereas the second spans amino acids 106-124. Recently, a C-terminal stability domain was identified spanning amino acids 170-189 [28]. Three previously identified phosphorylation sites are indicated: Ser-70, Thr-174, and Ser-177 [39]. (B) Illustration of the S-tagged Rex-1 (S-Rex-1) expression vector construct (not drawn to scale). (C) To determine the subcellular localization of the S-tagged Rex-1, HeLa-Tat cells were transfected with 1 μg of S-Rex-1 or wtRex-1 expression plasmids. At 24 h post-transfection, cells were stained with rabbit α-Rex-1 specific antisera (Green). Nuclei were stained with DAPI (Blue). (D) Western blot of Rex-1 proteins expressed in 293T cells transiently transfected with S-Rex-1 and wtRex-1 cDNA plasmids. Proteins as indicated were detected using rabbit α-Rex-1 specific antisera.