Production of Guide RNAs in vitro and in vivo for CRISPR Using Ribozymes and RNA Polymerase II Promoters

CRISPR/Cas9-mediated genome editing relies on a guide RNA (gRNA) molecule to generate sequence-specific DNA cleavage, which is a prerequisite for gene editing. Here we establish a method that enables production of gRNAs from any promoters, in any organisms, and in vitro (Gao and Zhao, 2014). This method also makes it feasible to conduct tissue/cell specific gene editing.