bHLH factors in neurogenesis and neuronal subtype specification

The basic helix-loop-helix (bHLH) family of transcription factors plays essential roles in neurogenesis and neuronal subtype specification. Neural bHLH transcription factors fall into at least two major subclasses—those that induce neuronal differentiation and others that inhibit this process to maintain cells in a stem or progenitor state. In addition, some bHLH factors function in specifying distinct neuronal subtypes, generating the neuronal diversity seen in mature nervous systems. The focus of this chapter is on genetic and molecular mechanisms by which neural bHLH factors regulate progenitors as they undergo neuronal differentiation and neuronal subtype specification and how they themselves are regulated.