Figure 4.

HIV-1 5′UTR IRES activity is decreased when nt 240–242 or 302–305 are mutated. The mutants studied here were previously found by Abbink et al. (55) to favor the BMH or the LDI conformation of the HIV-1 5′UTR (see the text). Mutations (boxes) or a deletion (filled triangle) are represented in the Weeks conformation and the conformation they favor is indicated. The WT and mutant IRES efficiencies were assessed in lysates from Jurkat T cells as described in the legend to Figure 2.