Figure 5

V3 loop alterations important for the association between CCR5 and FPRL usage. (A), luciferase reporter viruses pseudotyped with Env mutants (M1 through M15), or unmodified 1109-E-10 and 1109-F-30 Envs were used to infect NP2-CD4/FPRL1 cells, and the levels of HIV-1 entry were determined as described in the Methods. Open bars indicate Envs where no detectable FPRL1 usage was observed, and shaded bars indicate Envs with detectable FPRL1 usage. The dotted line indicates the limit of detection of coreceptor activity, as determined by infections with luciferase reporter virus pseudotyped with the non-functional ∆KS Env [44]. The results shown are a compilation of 3 independent experiments, each performed in triplicate. The data shown are means, and the error bars represent standard errors of the means. (B), summary of descriptions of the Env mutants. Shaded rows illustrate the Env mutants which had detectable FPRL1 usage. The R318P mutation, which was strongly associated with both CCR5 and FPRL1 usage, is highlighted in bold. The primary coreceptor specificity of the Env mutants (ie., whether they exhibit an R5, R5X4 or X4 phenotype) was determined previously [8]. (C), comparisons of the V3 loop region between the R5 1109-E-10 and X4 1109-F-30 Envs. Shown in bold are the amino acids tested by mutagenesis for modulation of FPRL1 usage, and boxed is the V3 crown motif shown to principally modulate FPRL1 usage.