FIG. 5.

Deletion mapping of PRA1 binding region in SIV gp41 CD. (A) A panel of deletion mutants of the SIV gp41 CD (SCD) were expressed as GAL4 BD fusions and tested for their ability to interact with PRA1 in a mammalian two-hybrid assay. The residues retained by each deletion construct are indicated as subscripts and correspond to the SIV gp41 CD sequence shown in panel B. Error bars indicate the standard deviations of duplicate transfections. (B) The predicted amino acid sequence of the SIV gp41 CD is numbered beginning with the first residue of the cytoplasmic domain. The underlined sequence indicates the region predicted to interact with PRA1. (C) Western blot showing the relative expression levels of selected deletions of the SIV gp41 CD. The sizes (shown in kilodaltons) of all expression products are consistent with the predicted sizes for each segment of the SIV gp41 CD fused to the GAL4 BD. Lysates from transfected 293 T cells were separated on a 14% polyacrylamide gel, transferred to a nylon membrane, and detected with a GAL4 BD-specific monoclonal antibody (Clontech).