BUILDING ZINC FINGERS BY SELECTION - TOWARD A THERAPEUTIC APPLICATION

A phage display approach was utilized to modify the specificity of eac h of the three fingers of the murine transcription factor Zif268. Sele ctions were performed by using the consensus binding sequence of the n atural protein and a conserved sequence in the genome of the type 1 hu man immunodeficiency virus. By using an extensive randomization strate gy, the entire 3-bp specificity of a finger has been changed. Rapid an alysis of selected zinc fingers was facilitated by the development of an immunoscreening assay for DNA binding and specificity. To investiga te the mechanism of binding and specificity, the binding kinetics of Z if268 and 10 selected variants were determined in real time with an as say based on surface plasmon resonance. Differential mechanisms for se quence-specific recognition were observed. No evidence in support of a single general coding relationship between zinc finger and target DNA sequence was observed. The prospects for the development of this clas s of proteins in human therapy are considered.