PlantTFDB
Plant Transcription Factor Database
v4.0
Previous version: v1.0, v2.0, v3.0
Aegilops tauschii
bHLH Family
Species TF ID Description
EMT01196bHLH family protein
EMT01225bHLH family protein
EMT01603bHLH family protein
EMT02714bHLH family protein
EMT02903bHLH family protein
EMT03037bHLH family protein
EMT03105bHLH family protein
EMT03129bHLH family protein
EMT03170bHLH family protein
EMT03543bHLH family protein
EMT03741bHLH family protein
EMT03936bHLH family protein
EMT04182bHLH family protein
EMT04374bHLH family protein
EMT05066bHLH family protein
EMT05067bHLH family protein
EMT05068bHLH family protein
EMT05069bHLH family protein
EMT05070bHLH family protein
EMT05397bHLH family protein
EMT05490bHLH family protein
EMT05766bHLH family protein
EMT06122bHLH family protein
EMT06747bHLH family protein
EMT06884bHLH family protein
EMT06885bHLH family protein
EMT07628bHLH family protein
EMT07709bHLH family protein
EMT07783bHLH family protein
EMT07811bHLH family protein
EMT07864bHLH family protein
EMT07976bHLH family protein
EMT08088bHLH family protein
EMT08157bHLH family protein
EMT08716bHLH family protein
EMT08749bHLH family protein
EMT09491bHLH family protein
EMT09799bHLH family protein
EMT09813bHLH family protein
EMT10296bHLH family protein
EMT10895bHLH family protein
EMT10961bHLH family protein
EMT11154bHLH family protein
EMT11155bHLH family protein
EMT11985bHLH family protein
EMT12426bHLH family protein
EMT13499bHLH family protein
EMT13532bHLH family protein
EMT13581bHLH family protein
EMT13985bHLH family protein
EMT14257bHLH family protein
EMT15172bHLH family protein
EMT15292bHLH family protein
EMT15399bHLH family protein
EMT15454bHLH family protein
EMT16023bHLH family protein
EMT16186bHLH family protein
EMT16314bHLH family protein
EMT16461bHLH family protein
EMT16496bHLH family protein
EMT16739bHLH family protein
EMT16792bHLH family protein
EMT17488bHLH family protein
EMT17812bHLH family protein
EMT18196bHLH family protein
EMT18288bHLH family protein
EMT18449bHLH family protein
EMT18454bHLH family protein
EMT18461bHLH family protein
EMT19490bHLH family protein
EMT19491bHLH family protein
EMT20093bHLH family protein
EMT20148bHLH family protein
EMT20218bHLH family protein
EMT20268bHLH family protein
EMT20279bHLH family protein
EMT20350bHLH family protein
EMT20393bHLH family protein
EMT20421bHLH family protein
EMT20704bHLH family protein
EMT20768bHLH family protein
EMT20899bHLH family protein
EMT21364bHLH family protein
EMT23685bHLH family protein
EMT23824bHLH family protein
EMT23827bHLH family protein
EMT23828bHLH family protein
EMT23829bHLH family protein
EMT24641bHLH family protein
EMT24926bHLH family protein
EMT25332bHLH family protein
EMT25485bHLH family protein
EMT26066bHLH family protein
EMT26125bHLH family protein
EMT26156bHLH family protein
EMT26157bHLH family protein
EMT26213bHLH family protein
EMT26223bHLH family protein
EMT26838bHLH family protein
EMT26974bHLH family protein
EMT27008bHLH family protein
EMT27133bHLH family protein
EMT27472bHLH family protein
EMT27513bHLH family protein
EMT27650bHLH family protein
EMT27723bHLH family protein
EMT27826bHLH family protein
EMT28039bHLH family protein
EMT28703bHLH family protein
EMT28775bHLH family protein
EMT28781bHLH family protein
EMT29569bHLH family protein
EMT29602bHLH family protein
EMT29957bHLH family protein
EMT29974bHLH family protein
EMT30222bHLH family protein
EMT30437bHLH family protein
EMT30687bHLH family protein
EMT30797bHLH family protein
EMT30818bHLH family protein
EMT32161bHLH family protein
EMT32260bHLH family protein
EMT32311bHLH family protein
EMT32548bHLH family protein
EMT32833bHLH family protein
EMT32961bHLH family protein
EMT33188bHLH family protein
EMT33309bHLH family protein
EMT33310bHLH family protein
EMT33311bHLH family protein
EMT33312bHLH 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