Zinc finger peptides for the regulation of gene expression.

Zinc fingers are small DNA-binding peptide motifs that were discovered in this laboratory. These motifs can be used as modular building blocks for the construction of larger protein domains that recognise and bind to specific DNA sequences. Phage display has been used to create a large library of different zinc fingers from which selections were made for binding to a given DNA sequence. From this database there have been elucidated elements of recognition rules that relate the amino acid sequence of a finger to its preferred DNA binding site. Control of gene expression using designed zinc finger peptides has been demonstrated by the specific inhibition of an oncogene mouse cell line and also by switching on genes in expression plasmids. These experiments demonstrate that zinc finger DNA-binding domains can be engineered de novo to recognise given DNA sequences. Five to six individual zinc fingers linked together would recognise a DNA sequence 15-18 bp in length, sufficiently long to constitute a rare address in the human genome. By adding functional groups to the engineered DNA-binding domains, e.g. silencing domains, novel transcription factors can be generated to up- or downregulate expression of a target gene. Among potential applications are the repression of oncogene expression and the disruption of the reproductive cycle of virus infection.