Acts as a negative regulator of transcription (By similarity). May function as a switch in neuronal development. In the developing embryo, restricted to the hypothalamus, dorsal thalamus, optic tectum, a region of the somatic motornucleus in the midbrain and hindbrain, the vestibular nuclei in the hindbrain, and a discrete ventral domain in the developing spinal cord. First expressed at stage 25. Expression peaks at stage 28 and continues at this level throughout all later stages, until at least stage 38.