PlantTFDB
Plant Transcription Factor Database
v4.0
Previous version: v1.0, v2.0, v3.0
Cannabis sativa
bHLH Family
Species TF ID Description
PK00207.1bHLH family protein
PK00238.1bHLH family protein
PK00238.2bHLH family protein
PK00381.1bHLH family protein
PK00939.1bHLH family protein
PK01043.1bHLH family protein
PK01364.1bHLH family protein
PK01498.1bHLH family protein
PK01503.1bHLH family protein
PK01630.1bHLH family protein
PK01802.1bHLH family protein
PK01904.1bHLH family protein
PK01904.2bHLH family protein
PK01904.3bHLH family protein
PK02334.1bHLH family protein
PK03241.1bHLH family protein
PK03295.1bHLH family protein
PK03576.1bHLH family protein
PK03768.1bHLH family protein
PK04509.1bHLH family protein
PK04767.1bHLH family protein
PK04856.1bHLH family protein
PK05451.1bHLH family protein
PK05923.1bHLH family protein
PK06301.1bHLH family protein
PK06517.1bHLH family protein
PK06696.1bHLH family protein
PK06841.1bHLH family protein
PK06916.1bHLH family protein
PK06940.1bHLH family protein
PK06970.1bHLH family protein
PK07850.1bHLH family protein
PK07858.1bHLH family protein
PK08539.1bHLH family protein
PK08705.1bHLH family protein
PK08747.1bHLH family protein
PK08792.1bHLH family protein
PK09009.1bHLH family protein
PK09009.2bHLH family protein
PK09122.1bHLH family protein
PK09702.1bHLH family protein
PK10562.1bHLH family protein
PK10562.2bHLH family protein
PK11573.1bHLH family protein
PK11667.1bHLH family protein
PK12073.1bHLH family protein
PK12098.1bHLH family protein
PK12518.1bHLH family protein
PK12518.2bHLH family protein
PK12627.1bHLH family protein
PK12634.1bHLH family protein
PK13304.1bHLH family protein
PK14040.1bHLH family protein
PK14093.1bHLH family protein
PK14284.1bHLH family protein
PK14657.1bHLH family protein
PK14736.1bHLH family protein
PK15168.1bHLH family protein
PK15358.1bHLH family protein
PK15505.1bHLH family protein
PK15505.2bHLH family protein
PK15531.1bHLH family protein
PK16670.1bHLH family protein
PK18038.1bHLH family protein
PK18401.1bHLH family protein
PK18474.1bHLH family protein
PK18533.1bHLH family protein
PK18828.1bHLH family protein
PK20089.1bHLH family protein
PK20184.1bHLH family protein
PK20225.1bHLH family protein
PK20397.1bHLH family protein
PK20553.1bHLH family protein
PK20816.1bHLH family protein
PK21055.1bHLH family protein
PK21055.2bHLH family protein
PK21140.1bHLH family protein
PK21234.1bHLH family protein
PK21294.1bHLH family protein
PK21748.1bHLH family protein
PK22680.1bHLH family protein
PK23013.1bHLH family protein
PK23084.1bHLH family protein
PK23205.1bHLH family protein
PK23355.1bHLH family protein
PK23387.1bHLH family protein
PK23555.1bHLH family protein
PK23618.1bHLH family protein
PK25041.1bHLH family protein
PK25264.1bHLH family protein
PK25419.1bHLH family protein
PK26582.1bHLH family protein
PK27921.1bHLH family protein
PK27964.1bHLH family protein
PK27980.1bHLH family protein
PK28391.1bHLH family protein
PK28434.1bHLH family protein
PK28516.1bHLH family protein
PK29179.1bHLH 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