Bacteria have evolved adaptive immune defenses called clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated (Cas) systems that use short RNA to direct the degradation of foreign nucleic acids. The type II bacterial CRISPR system has been engineered to function with custom guide RNA (gRNA) in human cells. This requires co-expression of a Cas9 protein with a nuclear localization signal with one or more gRNAs. Cas9 unwinds the DNA duplex and cleaves both strands upon recognition of a target sequence by the gRNA. This system has recently been used as a faster and more efficient way to edit host genomes to generate gene knockouts both in cells lines and animal models. My project focuses on targeting molecules involved in B cell development for in vitro work and eventually in vivo.