Application of the dual-luciferase reporter assay to the analysis of promoter activity in Zebrafish embryos

Background: The dual-luciferase assay has been widely used in cell lines to determine rapidly but accurately the activity of a given promoter. Although this strategy has proved very useful, it does not allow the promoter and gene function to be analyzed in the context of the whole organism. Results: Here, we present a rapid and sensitive assay based on the classical dual-luciferase reporter technique which can be used as a new tool to characterize the minimum promoter region of a gene as well as the in vivo response of inducible promoters to different stimuli. We illustrate the usefulness of this system for studying both constitutive (telomerase) and inducible (NF-kappa B-dependent) promoters. The flexibility of this assay is demonstrated by induction of the NF-kappa B-dependent promoters using simultaneous microinjection of different pathogen-associated molecular patterns as well as with the use of morpholino-gene mediated knockdown. Conclusion: This assay has several advantages compared with the classical in vitro (cell lines) and in vivo (transgenic mice) approaches. Among others, the assay allows a rapid and quantitative measurement of the effects of particular genes or drugs in a given promoter in the context of a whole organism and it can also be used in high throughput screening experiments.