<i>pIGLET</i>: Safe harbor landing sites for reproducible and efficient transgenesis in zebrafish.

Abstract

Standard zebrafish transgenesis involves random transgene integration with resource-intensive screening. While phiC31 integrase-based <i>attP</i>/<i>attB</i> recombination has streamlined transgenesis in mice and <i>Drosophila</i>, validated <i>attP</i>-based landing sites for universal applications are lacking in zebrafish. Here, we developed <i>phiC31 Integrase Genomic Loci Engineered for Transgenesis</i> (<i>pIGLET</i>) as transgenesis approach, with two <i>attP</i> landing sites <i>pIGLET14a</i> and <i>pIGLET24b</i> from well-validated Tol2 transgenes. Both sites facilitate diverse transgenesis applications including reporters and Cre/<i>loxP</i> transgenes. The <i>pIGLET14a</i> and <i>pIGLET24b</i> landing sites consistently yield 25 to 50% germline transmission, substantially reducing the resources needed for transgenic line generation. Transgenesis into these sites enables reproducible expression patterns in F0 zebrafish embryos for enhancer discovery and testing of gene regulatory variants. Together, our new landing sites streamline targeted, reproducible zebrafish transgenesis as a robust platform for various applications while minimizing the workload for generating transgenic lines.