ZINC-FINGER PHAGE - AFFINITY SELECTION OF FINGERS WITH NEW DNA-BINDING SPECIFICITIES

A phage display system was developed and used to select zinc finger pr oteins with altered DNA-binding specificities. The three zinc fingers of the Zif268 protein were expressed on the surface of filamentous pha ge, and a library of variants was prepared by randomizing critical ami no acids in the first zinc finger. Affinity selections, using DNA site s with base changes in the region recognized by the first finger, yiel ded Zif268 variants that bound tightly and specifically to the new sit es. This phage system provides a tool for the study of protein-DNA int eractions and may offer a general method for selecting zinc finger pro teins that recognize desired target sites on double-stranded DNA.