HES5, also known as bHLHb38, has a particular type of basic domain (presence of a helix-interrupting proline) that binds to the N-box (CACNAG), rather than the canonical E-box (CANNTG). HES5 is expressed in fetal heart and brain tumors. HES5 as a transcriptional repressor of genes that require a bHLH protein for their transcription and plays an important role as neurogenesis negative regulator.
