The invention relates to an interacting polypeptide consisting of or comprising a heptapeptide pattern of sequence X.sub.1X.sub.2X.sub.3X.sub.4X.sub.5X.sub.6X.sub.7 and a transduction domain, characterized in that it is a chimera polypeptide, the amino acid X.sub.7 is located between 5 and 35 amino acids of the C-terminal end of said polypeptide, and that the domain (b) is situated in C-terminal relative to pattern (a). The invention also relates to screening methods for identifying interacting polypeptides capable of modifying the phenotype of a cell and to uses of interacting polypeptides as mentioned in phenotypic screens or for therapeutic purposes. Lastly, the invention concerns interacting polypeptides capable of modifying the function of the HIV-1 Rev viral protein.