Abstract: Cis-acting repression sequences which are able to provide a cis-acting inhibitory effect on the expression of a gene when placed downstream of the gene in its untranslated message are dislcosed. Cis-acting anti-repression sequences which can relieve the cis-acting repression in the presence of the art gene product are also disclosed. These sequences correspond to a sufficient number of nucleotides from the HIV-I, HIV-2, STLV-3 or HTLV-IV genomes to provide the repression or anti-repression effects. The use of the sequences in vectors and systems to control the expression of a desired gene product is also described.

Abstract: A gene and gene product that regulates the expression of the capsidal envelope genes of HTLV-III/LAV and that can be used to regulate the expression of heterologous (non-viral) genes as well is disclosed. This art gene consists of two exons and can be used in creating nucleotide segments, vectors and cell lines. A new method for screening for compounds that inhibit the replication of HTLV-III is also described and comprises:(1) transfecting a T-cell line with the HTLV-III art and env genes;(2) thereafter, adding a preselected compound to the transformed cell line in increasing concentrations; and(3) determining whether the compound effects the art function without being toxic to the cell.An additional parameter to use in diagnosis of AIDS disease is also described. The use of the art gene and gene product in AIDS therapy is also disclosed.

Abstract: This invention describes stable tat.sub.III cell lines. It is disclosed that by transfecting a preselected tat.sub.III cell line with a vector containing a sufficient amount of the HTLV-III LTR responsive to tat.sub.III gene products for trans-activation and an enhancer upstream of the tat.sub.III responsive segment, it is possible to express high levels of the tat.sub.III gene products. By including a preselected heterologous gene on this vector, it is also possible to express high levels of a desired gene product. A substantially pure protein comprising 86 amino acids and having an apparent molecular weight of about 14,000 dalton and exhibiting trans-activating activity is also disclosed. This protein and polypeptides having trans-activating ability, which is also disclosed, can be used to produce high levels of a desired gene product.

Abstract: A gene and gene product that regulates the expression of the capsidal envelope genes of HTLV-III/LAV and that can be used to regulate the expression of heterologous (non-viral) genes as well is disclosed. This art gene consists of two exons and can be used in creating nucleotide segments, vectors and cell lines. A new method for screening for compounds that inhibit the replication of HTLV-III is also described and comprises:(1) transfecting a T-cell line with the HTLV-III art and env genes;(2) thereafter, adding a preselected compound to the transformed cell line in increasing concentrations; and(3) determining whether the compound effects the art function without being toxic to the cell.An additional parameter to use in diagnosis of AIDS disease is also described. The use of the art gene and gene product in AIDS therapy is also disclosed.