Probably acts synergistically with sop-2 to maintain the transcriptionally repressive state of homeotic genes in order to regulate various neurogenic identities. Specification of some neuronal identities also involves expression of non-Hox genes. Specifies dopaminergic and serotonergic neuronal cell fate, and regulates neurotransmitter choice and axon pathfinding. Expressed ubiquitously. Expressed in embryos, larvae and adults. Worms exhibit ectopic expression of Hox genes and homeotic transformations. Mutants are also long and exhibit defects in distal tip cell migration.