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bioRxiv · 10.64898/2026.05.12.724650

A transgenic zebrafish for direct optogenetic activation of FGF/ERK signaling

Anderson, W. K.·Iannucci, L. E.·Sinaii, N.·Porcino, J.·Rogers, K. W.
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Abstract

Dynamic FGF/ERK signaling plays key roles in development, regeneration, and disease. We recently developed a zebrafish-optimized optogenetic tool, bOpto-FGF, that enables reversible activation of FGF/ERK signaling in response to blue light ([~]455 nm) by fusing a zebrafish receptor tyrosine kinase domain to the blue light-dimerizing LOV domain. Previously, this tool was introduced into zebrafish embryos by mRNA injection. Here, we develop Tg(ubi:bOpto-FGF), a novel transgenic zebrafish ubiquitously expressing bOpto-FGF, to streamline experimental workflows. We demonstrate robust blue light-mediated activation of FGF/ERK signaling and FGF target gene expression in early gastrulation-stage Tg(ubi:bOpto-FGF) embryos. Light-mediated signaling activation at this stage is more spatially uniform in transgenics compared to mRNA-injected embryos, and ectopic signaling in response to continuous light exposure is activated within 3 minutes and maintained for at least 75 minutes. Further, Tg(ubi:bOpto-FGF) heterozygotes are light-responsive from late blastula stages through at least 24 hours post-fertilization. Finally, we demonstrate light-mediated spatially localized FGF/ERK signaling activation within 1 minute in the head, trunk, and tail at 1 day post-fertilization. This transgenic line provides a powerful and convenient new strategy for spatiotemporal manipulation of FGF/ERK signaling dynamics in the vertebrate zebrafish model. Summary StatementNovel transgenic zebrafish provides precise optogenetic control of a key developmental signaling pathway in vivo

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Anderson, W. K., Iannucci, L. E., Sinaii, N., Porcino, J., Rogers, K. W.. 2026-05-13. A transgenic zebrafish for direct optogenetic activation of FGF/ERK signaling. https://doi.org/10.64898/2026.05.12.724650

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