full length plasmid clone of proviral HIV-1; construct produces defective HIV-1 upon transfection into eukaryotic cells (frame-shift in gag); based on NL-BX
full length plasmid clone of proviral HIV-1; construct produces HIV-1 proteins upon transfection into eukaryotic cells but is non-infectious due to a protease-inactivating mutation in the catalytic centre of the protein (D25N); virus is based on NL-BX