O HIV-1. The 24 stem-loops were similarly inserted in an HIV-1 vector, and a packaging-deficient version was created by deleting the four adjacent stemloops (SL1 to SL4) upstream of the 5 portion of the gag gene and 40 bp of the gag gene (Fig. 1E). To visualize HIV-1 Gag, we fused CFP to its C terminus (Fig. 1F). Similar to FIV Gag-CFP, HIV-1 Gag-CFP is incorporated into viral particles (data not