CRISPR/Cas9-Directed Gene-Editing for the generation of loss-of–function mutants in high-throughput zebrafish FO screens

The ability to perform reverse genetics in the zebrafish model organism has been greatly advanced with the advent of the CRISPR (clustered regularly interspaced short palindromic repeats)/Cas9 (CRISPR-associated) system. The high level of efficiency in generating mutations when using the CRISPR/Cas9 system combined with the rapid generation time of zebrafish model organism has made the possibility of performing F 0 screens in this organism a reality. This Unit describes a detailed protocol for performing an F 0 screen using the CRISPR/Cas9 system in zebrafish starting with the design and production of custom CRISPR/Cas9 reagents for injection. Next, two approaches for determining the efficiency of mutation induction by the custom CRISRP/Cas9 reagents that is easily performed using standard molecular biology protocols are detailed. Finally, screening for F 0 induced phenotypes using the zebrafish flh gene as an example is discussed.