Mash1 is a member of the basic helix-loop-helix (BHLH) family of transcription factors. This protein activates transcription by binding to the E box (5'-CANNTG-3'). Dimerization with other BHLH proteins is required for efficient DNA binding. This protein plays a role in the neuronal commitment and differentiation and in the generation of olfactory and autonomic neurons. Mutations in the gene encoding Mash1 may contribute to the congenital central hypoventilation syndrome (CCHS) phenotype in rare cases.