Transcriptional regulator. Activates transcription by binding to the E box-containing promoter (By similarity). Mediates neuronal differentiation. Required for the development of Rohon-Beard spinal sensory neurons and dorsal root ganglion neurons, but not for primary motoneurons or autonomic neurons. Required for development of all cranial ganglia but not associated glial cells. Regulates epiphysial neurogenesis, acting partially redundantly with ascl1a and downstream of flh. Required for the development of basal forebrain dopaminergic neurons; involved in the specification of dopaminergic progenitor cells. May be involved in maintaining rhombomere boundaries in the hindbrain. Efficient DNA binding requires dimerization with another bHLH protein. 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. First detected at the late gastrulation stage (9 hpf). Strongly expressed in distinct domains in the neural plate at the 3-somite stage. First expressed in the epiphysis at around 14 hpf.