Schematic of LMP1 constructs and single cycle SIV genome. (A) Representation of LMP1 functional domains and the LMP1-CD40 chimeric protein. The LMP1 N-terminal transmembrane region enables the formation of clusters in the plasma membrane. This clustering is essential for LMP1 activity. In the LMP1-CD40 fusion protein, the cell signaling C-terminal region of LMP1 has been replaced and amino acid 190 of LMP1 is linked to the intracellular domain of the CD40 receptor, beginning at amino acid 220 the CD40 protein. (B) Schematic of scSIV viral genome. The parent vector, expressing GFP from the Nef promoter, was cloned by overlap PCR and inserted into the SIVmac239 FS-ΔPR-ΔINEGFP vector using unique XbaI and SacII sites. To create immunostimulatory forms of scSIV, LMP1 or LMP1-CD40 were inserted in place of the GFP gene as shown.