Selective labeling of central and peripheral sensory neurons in the developing zebrafish using P2X(3) receptor subunit transgenes.

The two paralogous P2X receptor subunit genes p2rx3.1 and p2rx3.2 are selectively expressed in overlapping, but unique, patterns of sensory neurons in the developing zebrafish. We constructed a series of transgenes derived from both genes using the recombineering technique. Transgenes utilizing either enhanced green fluorescent protein or monomeric red fluorescent protein-1 were shown to be expressed with the same spatial and temporal patterns as the native genes. The p2rx3.1-derived transgenes labeled the vast majority of the Rohon-Beard neurons in the spinal cord and neurons of the trigeminal ganglia. The p2rx3.2-derived transgene labeled fewer Rohon-Beard and trigeminal neurons than what was observed for the p2rx3.1-derived transgenes, but was also detected in neurons of the epibranchial ganglia. Three distinct populations of sensory neurons were detected: those expressing only one or the other paralog, and those expressing both paralogs. The fluorescent proteins encoded by the transgenes allowed for visualization of the neuronal somas as well as their peripheral and central projections. These reagents should prove extremely useful in providing the basis for future studies aimed at elucidating the developmental and physiological attributes of sensory neurons.