Embryonic nervous system. Expressed transiently in neurogenic placodes prior to delamination and formation of cranial ganglia. Expressed early (6-somite stage) in Rohon-Beard spinal sensory neurons and later in neural crest-derived dorsal root ganglion neurons. At 24 hours post-fertilization (hpf), expressed in specific regions of the brain and spinal cord. In hindbrain, expressed in presumptive neuroblasts adjacent to the rhombomere boundaries. In basal forebrain, expressed in dopaminergic progenitor cells.