Abstract: Novel defective adenoviruses for the transfer and expression of an exogenous nucleotide sequence in a host cell or organism. The invention also relates to novel complementation lines and to the process for the preparation of these novel defective adenoviruses and their use in therapy and to a pharmaceutical composition containing same.

Abstract: A composition resulting from a combination of trans-dominant variants of two viral proteins from a single virus, and the use thereof as a combination product are disclosed. A vector for expressing the two variants, a eukaryotic cell containing same, and a pharmaceutical composition for treating viral infections, are also disclosed.

Abstract: The human immunodeficiency virus type 1 (HIV-1) contains the canonical genes gag, pol, env, tat, rev, vif, vpr, vpu, and nef. The tat gene encodes an early regulatory protein that transactivates viral gene expression through interactions with a trans-activation responsive region (TAR). The instant invention is directed toward nucleic acids encoding site-directed trans-dominant Tat variants with reduced trans-activation capabilities as compared to wild-type. These variants are also capable of inhibiting wild-type Tat activity when present in the appropriate molar concentrations. Tat mutants were constructed by introducing single amino acid substitutions at positions 38, 40, 41, 45, and 47 of the wild-type coding region. A further aspect of the invention is directed toward expression cassettes containing these nucleic acids and methods of producing them. These reagents should prove useful in the identification of anti-viral compounds.