OTX2 encodes a member of the bicoid sub-family of homeodomain-containing transcription factors. The encoded protein acts as a transcription factor and may play a role in brain and sensory organ development. A similar protein in mice is required for proper forebrain development. Two transcript variants encoding distinct isoforms have been identified for this gene. Other alternative splice variants may exist, but their full length sequences have not been determined.Otx2 deficiency converted differentiating photoreceptor cells to amacrine-like neurons, reflecting a change in progenitor cell fate, and led to a total lack of pinealocytes in the pineal gland. Expression studies suggested that Otx2 is a direct upstream regulator of another cone-rod homeobox-containing gene, Crx, via binding to specific consensus sequences in the Crx promoter.