N-Oct 3 is a human POU domain transcription factor that binds to the octamer sequence ATGCAAAT. The protein is expressed in the central nervous system during development and in adult brain. We have isolated and characterized genomic clones encoding the human N-Oct 3 gene (HGMW-approved symbol POUF3). Comparison of the structure of these clones with the N-Oct 3 cDNA revealed that POUF3 is an intronless gene. Sequencing of 650 bp of the promoter region showed 84% sequence identity of POUF3 with its murine homologue, the brain-2 (designated brn-2) gene. Whereas both POUF3 and brn-2 lack a TATA box, consensus sequences for AP-2, GCF, and SP1 transcription factors were identified within the highly conserved 5'-flanking region. These sequences may play a crucial role for the tissue-specific transcription activation of the POUF3 gene. Southern blotting and in situ hybridization localized the human POUF3 gene to chromosome 6q16.