Gal4/UAS transgenic tools and their application to zebrafish

Abstract

The ability to regulate gene expression in a cell-specific and temporally restricted manner provides a powerful means to test gene function, bypass the action of lethal genes, label subsets of cells for developmental studies, monitor subcellular structures, and target tissues for selective ablation or physiological analyses. The galactose-inducible system of yeast, mediated by the transcriptional activator Gal4 and its consensus UAS binding site, has proven to be a highly successful and versatile system for controlling transcriptional activation in Drosophila. It has also been used effectively, albeit in a more limited manner, in the mouse. While zebrafish has lagged behind other model systems in the widespread application of Gal4 transgenic approaches to modulate gene activity during development, recent technological advances are permitting rapid progress. Here we review Gal4-regulated genetic tools and discuss how they have been used in zebrafish as well as their potential drawbacks. We describe some exciting new directions, in large part afforded by the Tol2 transposition system, that are generating valuable new Gal4/UAS reagents for zebrafish research.

FIG. 1.

UAS-regulated transgenic tools for subcellular labeling. All embryos were generated by crossing transgenic UAS reporter lines with a stable BAC transgenic line expressing Gal4-VP16 under the control of ptf1a regulatory elements. (A, B) Mitochondrial labeling from a 14 × UAS:cox5a-eGFP fusion in the hindbrain (shown at low power in inset in A). (C) Nuclear localization of 14 × UAS:hmgb1-GFP in hindbrain neurons. (D) Membrane-targeted 14 × UAS:mCherry-CAAX expression outlines the morphology of spinal cord interneurons. (A) and (B) are dorsal views with embryos oriented with anterior to the left, (C) is a dorsal view with anterior to the top, and (D) is a lateral view. Constructs and transgenic lines are available upon request.