OTX2 protein, also known as orthodenticle homeobox 2, is a transcription factor encoded by the OTX2 gene and belongs to the homeobox-containing gene family. It plays crucial roles in various developmental processes, particularly in the formation and function of the central nervous system. OTX2 is highly expressed in the brain, including regions such as the cerebral cortex and cerebellum. This protein is also involved in the development of the retina, where it is expressed in photoreceptors and bipolar cells. Additionally, OTX2 has been implicated in non-cell-autonomous activities, meaning it can influence neighboring cells through diffusion and interaction. Abnormalities in the OTX2 gene have been associated with conditions like microphthalmia and pituitary hormone deficiency. Recent studies also suggest a potential link between OTX2 and major depressive disorders.