A reporter-assisted mutagenesis screen using alpha 1-tubulin-GFP transgenic zebrafish uncovers missteps during neuronal development and axonogenesis.

Alpha1-tubulin expression occurs in a neural-specific, temporally regulated, and regeneration-inducible fashion in zebrafish. A GFP reporter driven by the alpha1-tubulin promoter in transgenic zebrafish acts as a stable, in vivo molecular tag that follows neuronal development from birth/specification through postmitotic differentiation to axonal outgrowth and synaptogenesis. We exploited this transgenic system in a reporter expression-dependent (morphology-independent) mutagenesis screen to identify disruptions in genetic loci essential for neuronogenesis and axon elaboration, which would manifest as visually appreciable perturbations in GFP fluorescence.

An element in the alpha1-tubulin promoter is necessary for retinal expression during optic nerve regeneration but not after eye injury in the adult zebrafish.

We have shown previously that a 1.696 kb upstream fragment of the goldfish alpha1-tubulin promoter was capable of driving green fluorescent protein (GFP) expression in the developing and regenerating zebrafish CNS in a pattern closely mimicking the endogenous alpha1-tubulin gene. Comparison of fish and rat alpha1-tubulin promoters identified a 64 bp region with a conserved repetitive homeodomain (HD) consensus sequence core (TAAT) and a nearby basic helix-loop-helix binding E-box sequence (CANNTG), which led us to speculate that it could be of importance for regulating alpha1-tubulin gene transcription.