The POU domain is a 150-160 amino acid region consisting of a 75-82 amino acid POU-specific domain, a shot variable linker region, and a 60 amino acid POU homeodomain. Originally found in three mammalian transcription factors and a Caenorhabditis elegans developmental control gene, this dmain has been identified in a growing number of genes. Research on the POU proteins ahs focused on their regulatory roles during development and the dissection of their functional domains to establish how they bind particular DNA sequences and activate transcription of distinct sets of genes. The pituitary-specific transcription factor Pit-1/GHF-1, the ubiquitous transcription factor Oct-1, and the predominantly B cell transcription factor Oct-2 have been the major subjects of biochemical dissection, while the developmental roles of Pit-1/GHF-1 and the C. elegans cell lineage control gene
unc-86 have been established by a combination of expression