PlantTFDB
Plant Transcription Factor Database
v4.0
Previous version: v1.0, v2.0, v3.0
Amborella trichopoda
bHLH Family
Species TF ID Description
evm_27.model.AmTr_v1.0_scaffold00001.432bHLH family protein
evm_27.model.AmTr_v1.0_scaffold00001.504bHLH family protein
evm_27.model.AmTr_v1.0_scaffold00002.15bHLH family protein
evm_27.model.AmTr_v1.0_scaffold00002.248bHLH family protein
evm_27.model.AmTr_v1.0_scaffold00002.492bHLH family protein
evm_27.model.AmTr_v1.0_scaffold00002.8bHLH family protein
evm_27.model.AmTr_v1.0_scaffold00005.174bHLH family protein
evm_27.model.AmTr_v1.0_scaffold00006.150bHLH family protein
evm_27.model.AmTr_v1.0_scaffold00006.196bHLH family protein
evm_27.model.AmTr_v1.0_scaffold00007.134bHLH family protein
evm_27.model.AmTr_v1.0_scaffold00008.115bHLH family protein
evm_27.model.AmTr_v1.0_scaffold00008.223bHLH family protein
evm_27.model.AmTr_v1.0_scaffold00009.103bHLH family protein
evm_27.model.AmTr_v1.0_scaffold00009.105bHLH family protein
evm_27.model.AmTr_v1.0_scaffold00009.224bHLH family protein
evm_27.model.AmTr_v1.0_scaffold00010.105bHLH family protein
evm_27.model.AmTr_v1.0_scaffold00010.380bHLH family protein
evm_27.model.AmTr_v1.0_scaffold00010.404bHLH family protein
evm_27.model.AmTr_v1.0_scaffold00011.126bHLH family protein
evm_27.model.AmTr_v1.0_scaffold00011.138bHLH family protein
evm_27.model.AmTr_v1.0_scaffold00013.209bHLH family protein
evm_27.model.AmTr_v1.0_scaffold00014.35bHLH family protein
evm_27.model.AmTr_v1.0_scaffold00015.95bHLH family protein
evm_27.model.AmTr_v1.0_scaffold00016.130bHLH family protein
evm_27.model.AmTr_v1.0_scaffold00016.96bHLH family protein
evm_27.model.AmTr_v1.0_scaffold00017.176bHLH family protein
evm_27.model.AmTr_v1.0_scaffold00019.433bHLH family protein
evm_27.model.AmTr_v1.0_scaffold00021.220bHLH family protein
evm_27.model.AmTr_v1.0_scaffold00021.51bHLH family protein
evm_27.model.AmTr_v1.0_scaffold00021.98bHLH family protein
evm_27.model.AmTr_v1.0_scaffold00022.303bHLH family protein
evm_27.model.AmTr_v1.0_scaffold00022.312bHLH family protein
evm_27.model.AmTr_v1.0_scaffold00024.331bHLH family protein
evm_27.model.AmTr_v1.0_scaffold00025.26bHLH family protein
evm_27.model.AmTr_v1.0_scaffold00025.64bHLH family protein
evm_27.model.AmTr_v1.0_scaffold00029.122bHLH family protein
evm_27.model.AmTr_v1.0_scaffold00029.85bHLH family protein
evm_27.model.AmTr_v1.0_scaffold00030.122bHLH family protein
evm_27.model.AmTr_v1.0_scaffold00032.24bHLH family protein
evm_27.model.AmTr_v1.0_scaffold00033.35bHLH family protein
evm_27.model.AmTr_v1.0_scaffold00036.88bHLH family protein
evm_27.model.AmTr_v1.0_scaffold00038.106bHLH family protein
evm_27.model.AmTr_v1.0_scaffold00038.2bHLH family protein
evm_27.model.AmTr_v1.0_scaffold00039.9bHLH family protein
evm_27.model.AmTr_v1.0_scaffold00041.167bHLH family protein
evm_27.model.AmTr_v1.0_scaffold00043.22bHLH family protein
evm_27.model.AmTr_v1.0_scaffold00043.85bHLH family protein
evm_27.model.AmTr_v1.0_scaffold00045.145bHLH family protein
evm_27.model.AmTr_v1.0_scaffold00046.26bHLH family protein
evm_27.model.AmTr_v1.0_scaffold00048.137bHLH family protein
evm_27.model.AmTr_v1.0_scaffold00049.187bHLH family protein
evm_27.model.AmTr_v1.0_scaffold00057.146bHLH family protein
evm_27.model.AmTr_v1.0_scaffold00063.45bHLH family protein
evm_27.model.AmTr_v1.0_scaffold00064.106bHLH family protein
evm_27.model.AmTr_v1.0_scaffold00065.157bHLH family protein
evm_27.model.AmTr_v1.0_scaffold00065.36bHLH family protein
evm_27.model.AmTr_v1.0_scaffold00066.230bHLH family protein
evm_27.model.AmTr_v1.0_scaffold00068.120bHLH family protein
evm_27.model.AmTr_v1.0_scaffold00070.121bHLH family protein
evm_27.model.AmTr_v1.0_scaffold00070.90bHLH family protein
evm_27.model.AmTr_v1.0_scaffold00071.86bHLH family protein
evm_27.model.AmTr_v1.0_scaffold00079.56bHLH family protein
evm_27.model.AmTr_v1.0_scaffold00084.29bHLH family protein
evm_27.model.AmTr_v1.0_scaffold00084.30bHLH family protein
evm_27.model.AmTr_v1.0_scaffold00089.12bHLH family protein
evm_27.model.AmTr_v1.0_scaffold00096.106bHLH family protein
evm_27.model.AmTr_v1.0_scaffold00098.54bHLH family protein
evm_27.model.AmTr_v1.0_scaffold00099.112bHLH family protein
evm_27.model.AmTr_v1.0_scaffold00100.19bHLH family protein
evm_27.model.AmTr_v1.0_scaffold00100.44bHLH family protein
evm_27.model.AmTr_v1.0_scaffold00100.58bHLH family protein
evm_27.model.AmTr_v1.0_scaffold00101.124bHLH family protein
evm_27.model.AmTr_v1.0_scaffold00102.17bHLH family protein
evm_27.model.AmTr_v1.0_scaffold00102.24bHLH family protein
evm_27.model.AmTr_v1.0_scaffold00106.97bHLH family protein
evm_27.model.AmTr_v1.0_scaffold00109.112bHLH family protein
evm_27.model.AmTr_v1.0_scaffold00110.8bHLH family protein
evm_27.model.AmTr_v1.0_scaffold00121.5bHLH family protein
evm_27.model.AmTr_v1.0_scaffold00129.99bHLH family protein
evm_27.model.AmTr_v1.0_scaffold00133.5bHLH family protein
evm_27.model.AmTr_v1.0_scaffold00135.31bHLH family protein
evm_27.model.AmTr_v1.0_scaffold00164.27bHLH family protein
evm_27.model.AmTr_v1.0_scaffold00167.5bHLH family protein
evm_27.model.AmTr_v1.0_scaffold00184.23bHLH 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