Homodimeric and Heterodimeric Interactions among Vertebrate Basic Helix-Loop-Helix Transcription Factors

The basic helix-loop-helix transcription factor (bHLH TF) family is involved in tissue development, cell differentiation, and disease. These factors have transcriptionally positive, negative, and inactive functions by combining dimeric interactions among family members. The best known bHLH TFs are the E-protein homodimers and heterodimers with the tissue-specific TFs or ID proteins. These cooperative and dynamic interactions result in a complex transcriptional network that helps define the cell's fate. Here, the reported dimeric interactions of 67 vertebrate bHLH TFs with other family members are summarized in tables, including specifications of the experimental techniques that defined the dimers. The compilation of these extensive data underscores homodimers of tissue-specific bHLH TFs as a central part of the bHLH regulatory network, with relevant positive and negative transcriptional regulatory roles. Furthermore, some sequence-specific TFs can also form transcriptionally inactive heterodimers with each other. The function, classification, and developmental role for all vertebrate bHLH TFs in four major classes are detailed.

Automated summary

The bHLH transcription factor family plays essential roles in tissue development, cell differentiation, and disease, with positive, negative, and inactive transcriptional functions. Dimeric interactions among family members, such as E-protein homodimers and heterodimers with tissue-specific TFs or ID proteins, contribute to a complex transcriptional network defining cell fate. The central role of homodimers of tissue-specific bHLH TFs in the regulatory network, as well as the formation of transcriptionally inactive heterodimers, are highlighted. Detailed information on function, classification, and developmental roles of vertebrate bHLH TFs in four major classes is provided.