Env (gp160) sequence evolution to CXCR4 use.

A. A phylogenetic tree representing the env clones that evolved from CCR5 to CXCR4 use. The tree is rooted with one of two variants found in the starting CC1/85 virus population with a TNNTxN motif sequence at position 459–465 (HXB2 numbering) in C5 instead of NDTSGT. All env clones that developed CXCR4 use were derived from this founder sequence. The weeks at which the env clones were isolated is indicated by the symbol legend, and the V3 sequence is indicated by the color given in the legend to Fig. 3. All env clones from week 36 and later of 5P12-RANTES selection were capable of using CXCR4 (see below), whereas only a subset of control env clones from week 44 or later were capable of entry via CXCR4. B. Entry data for env clones from weeks 36, 42, and 44 either from control cultures (open symbols) or 5P12-RANTES containing cultures (closed symbols, weeks depicted as in Fig. 4A). The symbols are color coded as in Figs. 3 and 4A.