Fig. 6From: Functional bottlenecks for generation of HIV-1 intersubtype Env recombinantsCloning of only V1-V5 domains of envA/D recombinants into NL4-3 backbone and the resultant envelope function assay. The V1-V5 domains of 9 envA/D recombinants were cloned into NL4-3 backbone, and were tested for their functionality by Veritrop assay (a) and for their ability to produce replication-competent viruses (b)Back to article page