PlantTFDB
Plant Transcription Factor Database
v4.0
Previous version: v1.0, v2.0, v3.0
Arachis hypogaea
bHLH Family
Species TF ID Description
Ahy001852bHLH family protein
Ahy001938bHLH family protein
Ahy003552bHLH family protein
Ahy003617bHLH family protein
Ahy003914bHLH family protein
Ahy005640bHLH family protein
Ahy005750bHLH family protein
Ahy007562bHLH family protein
Ahy007907bHLH family protein
Ahy007955bHLH family protein
Ahy008129bHLH family protein
Ahy008647bHLH family protein
Ahy009091bHLH family protein
Ahy009141bHLH family protein
Ahy009593bHLH family protein
Ahy009616bHLH family protein
Ahy010616bHLH family protein
Ahy010770bHLH family protein
Ahy010859bHLH family protein
Ahy010899bHLH family protein
Ahy010960bHLH family protein
Ahy011487bHLH family protein
Ahy012355bHLH family protein
Ahy012362bHLH family protein
Ahy012380bHLH family protein
Ahy013004bHLH family protein
Ahy013744bHLH family protein
Ahy013885bHLH family protein
Ahy013892bHLH family protein
Ahy014185bHLH family protein
Ahy014210bHLH family protein
Ahy014270bHLH family protein
Ahy014364bHLH family protein
Ahy014421bHLH family protein
Ahy014425bHLH family protein
Ahy014876bHLH family protein
Ahy015780bHLH family protein
Ahy016031bHLH family protein
Ahy016096bHLH family protein
Ahy016401bHLH family protein
Ahy016597bHLH family protein
Ahy016753bHLH family protein
Ahy018336bHLH family protein
Ahy018549bHLH family protein
Ahy018850bHLH family protein
Ahy018913bHLH family protein
Ahy018937bHLH family protein
Ahy020163bHLH family protein
Ahy020531bHLH family protein
Ahy020848bHLH family protein
Ahy020948bHLH family protein
Ahy021200bHLH family protein
Ahy021736bHLH family protein
Ahy021755bHLH family protein
Ahy021846bHLH family protein
Ahy022057bHLH family protein
Ahy022208bHLH family protein
Ahy022602bHLH family protein
Ahy022707bHLH family protein
Ahy003925bHLH family protein
Ahy008559bHLH family protein
Ahy009270bHLH family protein
Ahy009525bHLH family protein
Ahy009800bHLH family protein
Ahy010491bHLH family protein
Ahy013609bHLH family protein
Ahy014072bHLH family protein
Ahy014599bHLH family protein
Ahy014805bHLH family protein
Ahy015983bHLH family protein
Ahy020255bHLH family protein
Ahy021290bHLH family protein
bHLH Family Introduction

The basic/helix-loop-helix (bHLH) proteins are a superfamily of transcription factors that have been well characterized in nonplant eukaryotes, especially in mammalian systems, in which considerable structural, functional, and phylogenetic analyses have been performed. The data indicate that bHLH proteins are important regulatory components in transcriptional networks in these systems, controlling a diversity of processes from cell proliferation to cell lineage establishment.

This family is defined by the bHLH signature domain, which consists of 60 amino acids with two functionally distinct regions. The basic region, located at the N-terminal end of the domain, is involved in DNA binding and consists of 15 amino acids with a high number of basic residues. The HLH region, at the C-terminal end, functions as a dimerization domain and is constituted mainly of hydrophobic residues that form two amphipathic -helices separated by a loop region of variable sequence and length. Outside of the conserved bHLH domain, these proteins exhibit considerable sequence divergence. Cocrystal structural analysis has shown that the interaction between the HLH regions of two separate polypeptides leads to the formation of homodimers and/or heterodimers and that the basic region of each partner binds to half of the DNA recognition sequence. Some bHLH proteins form homodimers or restrict their heterodimerization activity to closely related members of the family. On the other hand, some can form heterodimers with one or several different partners.

The core DNA sequence motif recognized by the bHLH proteins is a consensus hexanucleotide sequence known as the E-box (5'-CANNTG-3'). There are different types of E-boxes, depending on the identity of the two central bases. One of the most common is the palindromic G-box (5'-CACGTG-3'). Certain conserved amino acids within the basic region of the protein provide recognition of the core consensus site, whereas other residues in the domain dictate specificity for a given type of E-box . In addition, flanking nucleotides outside of the hexanucleotide core have been shown to play a role in binding specificity, and there is evidence that a loop residue in the protein plays a role in DNA binding through elements that lie outside of the core recognition sequence.

Toledo-Ortiz G, Huq E, Quail PH.
The Arabidopsis basic/helix-loop-helix transcription factor family.
Plant Cell. 2003 Aug;15(8):1749-70
PMID: 12897250