Production and Quantification of HIV-1-GFP Viruses

HIV-1-GFP single-round infectious viruses were produced by co-transfecting 293T cells with a 1:1:1 ratio of three plasmids: pVSV-G, pCSGW (GFP-reporter) and pCMVΔ8.91 (or pCMVΔ8.91 mutants). Approximately 16 h post-transfection, cells were treated with 10 mM sodium butyrate for 8 h and VLP-containing supernatants were harvested 24 h later. Viral titres were quantified using the Taq-PERT assay to measure viral reverse transcriptase activity [41 (link),42 (link)] or, for reverse transcriptase mutants, the Alliance HIV-1 p24 Antigen ELISA from Perkin-Elmer (NEK050B001KT), following the manufacturer’s instructions. GFP expression was detected on a ZOE fluorescent Cell Imager (BIO-RAD).