Engineered Cys 2 His 2 zinc finger DNA-binding domains

Gene therapy reagents such as artificial transcription factors and site-specific endonucleases require "made-to-order" DNA-binding domains with high affinity and specificity for novel target sequences. Cys2His2 zinc finger proteins are the best understood and most commonly used framework for design and selection of such domains. Though a number of design strategies have been described in the literature, they vary significantly in their reliability and ease of execution. This situation has made it difficult for the non-specialist researcher to know how best to construct zinc finger proteins for their application of interest. This article reviews the current state of the technology and its limitations, and discusses prospects for improving our ability to make customized DNA-binding modules.