A novel cyp26c1-driven reporter line to study boundaries of retinoic acid signalling during zebrafish development.

Retinoic acid (RA) signalling is essential for vertebrate development, but the spatiotemporal dynamics of its regulation remain largely uncharacterized in specific cellular contexts. Here, we introduce a novel gene trap transgenic reporter line for the zebrafish cyp26c1 gene, a key regulator of RA metabolism. Through a screen of a gal4-based gene and enhancer trap collection, we isolated the tg(gSAIGFF104A) line. In this line, a gal4 gene trap cassette is inserted into the third intron of the cyp26c1 gene, allowing it to faithfully drive reporter expression in a pattern that mirrors the endogenous cyp26c1 expression in zebrafish embryos. Using this reporter, we characterized the expression of cyp26c1 with cellular resolution, revealing a highly dynamic and localized expression in the developing telencephalon, diencephalon, hindbrain, otic vesicles, pharyngeal arches, and other ectodermal derivatives, as well as in subdomains of the retina. Furthermore, we demonstrate that this line responds to both exogenous and genetic manipulations of RA signalling, particularly within the retina. Our reporter provides a valuable resource for investigating the intricate biology of RA signalling in zebrafish development and disease, offering a tool for tracing and manipulating cyp26c1-expressing cells.