In Vivo Applications of Cell-Penetrating Zinc-Finger Transcription Factors.

Artificial transcription factors based on zinc finger, TALE, and CRISPR/Cas9 programmable DNA-binding platforms have been widely used to regulate the expression of specific genes in cultured cells, but their delivery into organs such as the brain represents a critical challenge to apply such tools in live animals. In previous work, we developed a zinc-finger-based artificial transcription factor harboring a cell-penetrating peptide (CPP) that could be injected systemically, cross the blood-brain barrier, and alter expression of a specific gene in the brain of an adult mouse. Importantly, our mode of delivery produced widespread distribution throughout the brain. Here we describe methods for the production and purification of the factor, testing CPP activity in cells, and testing CPP activity in mice.