SEVERAL genes have been identified that affect the specification of unique neuronal identities during development of the Drosophila central nervous system1-7. At least two of these genes, fushi tarazu (ftz)4 and even-skipped (eve)5 share a common structural motif, the homoeobox, which encodes a sequence-specific DNA-binding domain (homoeodomain)8. A family of related proteins has been recently characterized in mammals and nematodes that contain a diverged homoeodomain as part of a structure referred to as a POU domain9-15. Mammalian genes encoding POLJ domains have region-specific patterns of expression in the central nervous system15, indicating a potential role for them in the regulation of neuronal development. The nematode POU-domain gene, unc-86, is involved in the determination of neuroblast lineages leading to serotonergic and dopaminergic neurons13,14. We have now identified a Drosophila gene, Cf1a, encoding a sequence-specific DNA-binding protein containing a highly conserved POU domain. The Cf1a gene product binds to a DNA element required for expression of the dopa decarboxylase gene (Ddc) in selected dopaminergic neurons, implying that it functions as a neuron-specific transcription factor. © 1990 Nature Publishing Group.