Zinc Finger Chimera - Engineered Zinc Finger Arrays

Engineered Zinc Finger Arrays

Generating arrays of engineered Cys₂His₂ zinc fingers is the most developed method for creating proteins capable of targeting desired genomic DNA sequences. The majority of engineered zinc finger arrays are based on the zinc finger domain of the murine transcription factor Zif268, although some groups have used zinc finger arrays based on the human transcription factor SP1. Zif268 has three individual zinc finger motifs that collectively bind a 9 bp sequence with high affinity. The structure of this protein bound to DNA was solved in 1991 and stimulated a great deal of research into engineered zinc finger arrays. In 1994 and 1995, a number of groups used phage display to alter the specificity of a single zinc finger of Zif268. Carlos F. Barbas et al. also reported the development of zinc finger technology in the patent literature and have been granted a number of patents that have been important for the commercial development of zinc finger technology. Typical engineered zinc finger arrays have between 3 and 6 individual zinc finger motifs and bind target sites ranging from 9 basepairs to 18 basepairs in length. Arrays with 6 zinc finger motifs are particularly attractive because they bind a target site that is long enough to have a good chance of being unique in a mammalian genome. There are two main methods currently used to generate engineered zinc finger arrays, modular assembly and a bacterial selection system, and there is some debate about which method is best suited for most applications.