To establish whether the source of immune stimulation during Gag-fusion virus infection was the viral genome, reverse transcripts, or a later stage of infection we generated Gag-LUC viruses that were defective for reverse transcription (Gag-LUC RT D185E) or integration (Gag-LUC INT D116N) by co-transfecting p8.91 Gag-pol carrying the RT D185E and INT D116N mutations. This evidence concerns the gene INTU and infection.