foxQ2 marks fast-acting interneurons including dopaminergic neurons of mushroom bodies and central complex in the beetle Tribolium castaneum.

Tc-foxQ2II marks subsets of fast-acting interneurons in the adult brain of Tribolium castaneum, including dopaminergic neurons, across nine projection-defined clusters.

• Why it matters: The specific roles of conserved brain transcription factors like foxQ2II in adult neuron type specification remain unclear, especially for their contributions to higher-order brain centers.
• What they did: Using enhancer trap, immunostainings, and a newly established beetle brainbow system, the authors categorized Tc-foxQ2II-positive neurons into nine clusters by projection patterns and neurotransmitter markers.
• The result: All nine clusters contained acetylcholine and glutamate neurons, none were GABA-ergic or serotonin-positive, and many dopaminergic neurons were Tc-foxQ2II-positive, homologizing to Drosophila PPL2c, PPM1, and PPL1; this links foxQ2 genes to interneurons in mushroom bodies and central complex.