Targeted expression of a chimeric channelrhodopsin in zebrafish under regulation of Gal4-UAS system

Channelrhodopsin (ChR)-wide receiver (ChRWR), one of the chimeric molecule of ChR1 and ChR2, has several advantages over ChR2 such as improved expression in the plasma membrane and enhanced photocurrent with small desensitization. Here we generated transgenic zebrafish (Danio rerio) expressing ChRWR as a conjugate of EGFP under the regulation of UAS promoter (UAS:ChRWR-EGFP). When crossed with a Gal4 line, SAGFF36B, ChRWR-EGFP was selectively expressed in primary mechanosensory Rohon–Beard (RB) neurons. The direct photoactivation of RB neurons was sufficient to trigger the escape behavior. The UAS:ChRWR-EGFP line could facilitate a variety of investigations of neural networks and behaviors of zebrafish in vivo.

► ChRWR is optimized for stimulating a neuron with low intensity of light. ► We generated UAS:ChRWR-EGFP line of zebrafish expressing ChRWR under UAS promoter. ► When crossed with an SAGFF36B line, ChRWR was expressed in Rohon–Beard neurons. ► The escape behavior was elicited by photoactivation of Rohon–Beard neurons. ► The UAS:ChRWR-EGFP line is an useful tool to study neuronal network of zebrafish.