Successful infection and production of new infectious viruses requires the balanced expression of seven additional viral proteins (Rev, Tat, Nef, Vif, Vpr, Vpu and Env) that are produced by splicing of the primary 9 kb transcripts among which the Tat and the Rev factors are absolutely required for viral gene expression at the transcriptional and post-transcriptional levels in infected cells [9,10]. Here, TAT is linked to infection.