A Phage Display System to Profile the DNA-binding Specificities of C2H2 Zinc Fingers

Knowing the sequence specificities of transcription factors allows us to surmise their functions and establish their regulatory roles in genomes. The most common DNA-binding domain among eukaryotic transcription factors is the Cys2His2 zinc finger domain; however, despite their prevalence, the specificities of the majority of Cys2His2 zinc finger proteins remain unknown due to the difficulty in assaying them. My objective was to develop a new phage displayed-based assay, in which individual Cys2His2 domains are displayed on phage in an otherwise constant three-finger protein scaffold. In Chapter 2, I discuss evidence for the modularity of the Cys2His2 domain, since my assay requires that zinc fingers be modular. In Chapter 3, I describe my results on the development of this phage display-based assay. This work provides support for a new strategy to determine the specificities of individual zinc fingers, which can be used to infer specificities for multi-finger Cys2His2 proteins.MAS