Transcription factor that may function as a switch in neuronal development. Keeps neural cells undifferentiated by counteracting the activity of proneural proteins and suppresses neuronal differentiation. First expressed in the embryonic neural plate shortly before closure and expression continues in the neural tube. From stage 16 onwards, expressed throughout the CNS including the brain, with expression predominant in the undifferentiated cells of the neural epithelium. Also expressed at a low level in the retina and the gut epithelium. Expression is maximal at stages 24-31, then begins to decline. Expression is absent by stage 37. Does not appear to be expressed in adults. The 9aaTAD motif is a transactivation domain present in a large number of yeast and animal transcription factors. It is uncertain whether Met-1 or Met-4 is the initiator.