Class E basic helix-loop-helix protein 23 (Bhlhe23, also known as Bhlhe4) is a basic helix-loop-helix (bHLH) transcription factor. In pancreas and brain, it marks the dimesencephalic boundary and may have a role in diencephalic regionalisation []. In retina, it is required for rod bipolar cell maturation [].The bHLH (basic Helix-Loop-Helix) proteins contain the bHLH domain that is approximately 60 amino acids long and consists of a DNA-binding basic region followed by two a-helices separated by a variable loop region (HLH). The HLH domain promotes dimerisation, allowing the formation of homo- or heterodimeric complexes between different family members. Many bHLH proteins have been shown to act as transcriptional regulators [].
