TRANSCRIPTIONAL REPRESSION BY ZINC-FINGER PEPTIDES - EXPLORING THE POTENTIAL FOR APPLICATIONS IN GENE-THERAPY

A series of studies were performed to determine whether zinc finger pe ptides could efficiently repress transcription from RNA polymerase Il promoters in vivo and to determine how such repression might depend on the position of the zinc finger binding site with respect to those of the TATA box or the initiator element. Promoter constructs were prepa red with Zif268 binding sites inserted at various positions, and the a ctivity of a reporter gene was measured in transfection studies. We fo und that the peptide containing the three zinc fingers of Zif268 could efficiently repress activated transcription when bound to a site near the TATA box (19-fold repression) or when bound to a site near the in itiator element (18-fold repression). Repression was even more effecti ve when the zinc finger peptide was bound to both of these sites (63-f old repression). Novel zinc finger peptides that had been selected via phage display also served as repressors of activated transcription, b ut repression with these proteins was somewhat less efficient than wit h the Zif268 peptide.