biostudies-literatureYin LIntramural NIH HHSNEI NIH HHSNIDDK NIH HHSNIGMS NIH HHS431-41https://www.ebi.ac.uk/biostudies/studies/S-EPMC4492370biostudies-literatureUnknown200(2)Determining the mechanism of gene function is greatly enhanced using conditional mutagenesis. However, generating engineered conditional alleles is inefficient and has only been widely used in mice. Importantly, multiplex conditional mutagenesis requires extensive breeding. Here we demonstrate a system for one-generation multiplex conditional mutagenesis in zebrafish (Danio rerio) using transgenic expression of both cas9 and multiple single guide RNAs (sgRNAs). We describe five distinct zebrafish U6 promoters for sgRNA expression and demonstrate efficient multiplex biallelic inactivation of tyrosinase and insulin receptor a and b, resulting in defects in pigmentation and glucose homeostasis. Furthermore, we demonstrate temporal and tissue-specific mutagenesis using transgenic expression ofGeneticsMultiplex Conditional Mutagenesis Using Transgenic Expression of Cas9 and sgRNAs.PMC4492370R21 GM110311DK088686R01 EY024354R01 DK088686Maddison LAVarshney GKKara NPatton JGChen WYin LLaFave MCBurgess SMLi MfalseMultiplex Conditional Mutagenesis Using Transgenic Expression of Cas9 and sgRNAs.Determining the mechanism of gene function is greatly enhanced using conditional mutagenesis. However, generating engineered conditional alleles is inefficient and has only been widely used in mice. Importantly, multiplex conditional mutagenesis requires extensive breeding. Here we demonstrate a system for one-generation multiplex conditional mutagenesis in zebrafish (Danio rerio) using transgenic expression of both cas9 and multiple single guide RNAs (sgRNAs). We describe five distinct zebrafish U6 promoters for sgRNA expression and demonstrate efficient multiplex biallelic inactivation of tyrosinase and insulin receptor a and b, resulting in defects in pigmentation and glucose homeostasis. Furthermore, we demonstrate temporal and tissue-specific mutagenesis using transgenic expression of2015-01-01T00:00:00Z2015 Jun2025-04-04T11:06:59.907Z2019-03-27T01:54:36ZS-EPMC44923702585506710.1534/genetics.115.176917