DARibo-Q: RNA Allosteric Transduction for Fluorescence Imaging of Dopamine Modulation in Living Systems

Precise regulation of dopamine signaling underlies diverse neuronal processes, yet methods that directly report intracellular dopamine-associated dynamics in living systems remain limited. Here, we present DARibo-Q, a genetically encoded RNA fluorescent biosensor that enables fluorescence imaging of intracellular dopamine-associated modulation through a rationally engineered RNA allosteric transduction architecture. By coupling dopamine recognition to graded shifts in RNA conformational equilibria, DARibo-Q converts ligand-associated changes into a continuous and interpretable optical output under physiological conditions rather than a threshold-based or amplification-dependent response. In neuronal cells, DARibo-Q reports relative dopamine-associated fluorescence changes and resolves mechanistically distinct modes of dopaminergic regulation, enabling mechanism-informed analysis of dopaminergic compounds. The sensor further supports in vivo visualization of drug-modulated dopamine dynamics in zebrafish. Together, this work demonstrates that RNA allostery can be engineered to achieve direct, relatively quantitative signal transduction of small-molecule neurotransmitters in living systems.