Acts as a transcriptional activator (PubMed:8290353, PubMed:7935408). Acts by binding to sequences related to the consensus octamer motif 5'-ATGCAAAT-3' in the regulatory regions of its target genes (PubMed:7935408). Involved in the auditory system development, required for terminal differentiation of hair cells in the inner ear (PubMed:8637595). Interacts with ISL1 (PubMed:24643061). Preferentially localized in the nucleus. Brain. Expressed in developing spinal cord from 13 dpc to postanal day 1, not expressed in adults (PubMed:8290353). Expressed by few neurons of dorsal root ganglion from, at least, 10.5 dpc to 15.5 dpc (PubMed:22326227). Mutants are deaf and show deficits in balance and coordination that become severe at about P14 and exhibit hyperactivity by 5-6 weeks. Belongs to the POU transcription factor family. Class-4 subfamily.