POU4F2 is a member of the POU-domain family of transcription factors. POU-domain proteins have been observed to play important roles in control of cell identity in several systems. A class IV POU-domain protein, POU4F2 is found in human retina exclusively within a subpopulation of ganglion cells where it may play a role in determining or maintaining the identities of a small subset of visual system neurons.The BRN3B gene encodes a 410-amino acid polypeptide that contains several identifiable motifs, including a glycine/serine-rich domain, a histidine-rich domain, and a POU domain. RNA slot blots showed that BRN3B is expressed predominantly in the retina. Immunocytochemistry indicated that the protein is present in the nuclei of a subset of retinal ganglion cells, consistent with its role as a transcription factor.