Neural induction: 10 years on since the ‘default model’

Neural induction is the process by which embryonic cells in the ectoderm make a decision to acquire a neural fate (to form the neural plate) rather than give rise to other structures such as epidermis or mesoderm. An influential model proposed a decade ago, the ‘default model’, postulated that ectodermal cells will become neurons if they receive no signals at all, but that this is normally inhibited in prospective epidermal cells by the action of bone morphogenetic proteins. Recent results now reveal considerable more complexity and emphasis is shifting from intercellular signalling factors to trying to understand the regulation of expression of key genes within the nucleus.