Transcription factor. Expressed in the developing urogenital system, eye and brain. First detected at 10.5 dpc in the gonadal component of the urogenital ridge. Expression dramatically increases by 11.5 dpc in the urogenital ridges and in the cranial surface ectoderm. At this time, it is also expressed in the trigeminal ganglion and nodose ganglion. At later stages, it is expressed in the brain and organs derived from the urogenital ridge, including the gonadal tubercle, kidneys, and adrenal glands. From 14.5 dpc to birth, expression is evident in the developing retinal neuroepithelium and the vibrissa. By PAX3 which regulates its expression. Mice are healthy and fertile and do not display any abnormal phenotype.