Transcription Factor Classes

Synonyms

DNA-binding domain motifs

Definition

Transcription factors (TFs) are proteins that interact with promoter and enhancer regions of genes to positively or negatively regulate gene expression. There are several discrete functional domains that most transcription factors contain including DNA-binding domains, protein-protein interaction domains, domains for intracellular trafficking signals, and ligand-binding domains. In particular, DNA-binding domains are highly conserved and often contain a short motif that fits into the major groove of DNA. There are roughly 12–15 unique DNA-binding domains found in eukaryotic TFs. TFs with similar structural motifs in the DNA-binding domain have been grouped into four classes which include helix-turn-helix (HTH) proteins, zinc finger proteins, leuciine zipper proteins, and helix-loop-helix proteins.

Discussion

The helix-turn-helix (HTH) is a conserved motif consisting of 20 amino acids in the form of an α-helix followed by a turn that is...