[Toward an unpublished method of detecting human retroviruses: activation of HIV-1 LacZ recombinant provirus by the tat gene product].

For a few of retroviruses, the level of synthesis of viral proteins is greatly increased in the presence of a transactivator gene which is encoded by the virus. For instance, for HIV, TAT acts on target sequences present in the viral long terminal repeat (LTR). HIV-1 recombinant retrovirus (RRV), where the gag, pol and part of env genes have been exchanged for the reporter nlsLacZ gene, expresses the reporter gene only in presence of TAT. When the RRV is tat defective, this activity can be complemented by tat present on a second molecule. The expression of nlsLacZ can then be detected by a simple histochemical staining. If this complementation can also be provided by a wild type virus, then their detection and titration would be greatly simplified.