The present invention describes novel transcriptional activators and activation systems. The activators of the present invention comprise a DNA binding moiety linked to a short peptide of novel sequence. Preferably, the peptide is substantially hydrophobic. Preferred peptides include at least one aromatic amino acid. The present invention also provides improved transcriptional activation systems, useful for the identification and characterization of protein--protein interactions. The invention also describes the production and use of certain TBP mutants that enhance transcriptional activation by some activators.