Abstract
The application of CRISPR has greatly facilitated genotype-phenotype studies of human disease models. In this protocol, we describe CRISPR-Cas9-induced gene knockout in zebrafish, utilizing purified Cas9 protein and in vitro-transcribed sgRNA. This protocol targets the PHLPP1 gene in an Indian wild-caught strain, but is broadly applicable. Major factors influencing protocol success include zebrafish health and fecundity, sgRNA efficiency and specificity, germline transmission, and mutant viability. For complete details on the use and execution of this protocol, please refer to Balamurugan et al. (2022).