FIG. 1.
Scheme for construction of recombinant HIV-1LAI DNAs encoding V3 loop sequences from the NH family. Overlapping primers 2 and 3 and outer primers 1 and 4 were used to generate recombinant DNA segments having the non-LAI V3 and LAI flanking sequences by the overlap extension method (17). The products were digested with StuI and NheI and cloned into the gp120 subclone (pUC-LAISB) made from pLAI (28). Subsequently, the SalI-BamHI fragment of pUC-LAISB was cloned into pLAI to reconstitute a full-length HIV-1 molecular clone. Nucleotide sequences of outside primers 1 and 4 are described in a previous report (34). LTR, long terminal repeat.