A versatile high throughput strategy for cloning the env gene of HIV-1

The trimeric envelope glycoprotein (gp120/gp41) 3 of human immunodeficiency virus-1 (HIV-1) mediates viral and host cell membrane fusion, initiated by binding of viral envelope gp120 protein to the CD4 receptor on host immune cells. Functional env genes from infected individuals have been widely used as templates for vaccine design, for setting up viral neutralization assays and to study the viral evolution and pathogenesis. Traditional topoisomerase or T4 DNA polymerase mediated approaches for cloning single genome amplified (SGA) env genes are labor-intensive, cost-ineffective with low-throughput, thereby enabling functional analysis of only a limited number of env genes from the diverse circulating quasispecies in infected individuals. Herein, we report an efficient, easy to optimize and high-throughput approach for cloning diverse HIV-1 env genes. Multiple env/rev gene cassettes, derived from infected infants, were subjected to SGA using Phusion polymerase and utilized as megaprimers in overlap extension PCR mediated cloning (OEC), circumventing the requirement for novel enzymes. Furthermore, utilization of Phusion polymerase for both the amplification of env/rev cassettes and OEC allows convenient monitoring and optimization, thereby providing much greater flexibility and versatility for analysis of env genes from HIV-1 infected individuals.