PlantTFDB
Plant Transcription Factor Database
v4.0
Previous version: v1.0, v2.0, v3.0
Actinidia chinensis
bHLH Family
Species TF ID Description
Achn000591bHLH family protein
Achn007901bHLH family protein
Achn008041bHLH family protein
Achn009641bHLH family protein
Achn013141bHLH family protein
Achn013161bHLH family protein
Achn017041bHLH family protein
Achn017831bHLH family protein
Achn021041bHLH family protein
Achn021861bHLH family protein
Achn023041bHLH family protein
Achn030051bHLH family protein
Achn030801bHLH family protein
Achn032761bHLH family protein
Achn033091bHLH family protein
Achn035131bHLH family protein
Achn039371bHLH family protein
Achn041401bHLH family protein
Achn041801bHLH family protein
Achn053731bHLH family protein
Achn054201bHLH family protein
Achn055521bHLH family protein
Achn056701bHLH family protein
Achn060771bHLH family protein
Achn061231bHLH family protein
Achn067431bHLH family protein
Achn069961bHLH family protein
Achn070961bHLH family protein
Achn071731bHLH family protein
Achn075131bHLH family protein
Achn084581bHLH family protein
Achn084621bHLH family protein
Achn087061bHLH family protein
Achn087151bHLH family protein
Achn087871bHLH family protein
Achn088091bHLH family protein
Achn088391bHLH family protein
Achn090241bHLH family protein
Achn091661bHLH family protein
Achn092921bHLH family protein
Achn096211bHLH family protein
Achn096511bHLH family protein
Achn096541bHLH family protein
Achn104421bHLH family protein
Achn104681bHLH family protein
Achn104991bHLH family protein
Achn105191bHLH family protein
Achn105951bHLH family protein
Achn106671bHLH family protein
Achn110081bHLH family protein
Achn111891bHLH family protein
Achn116251bHLH family protein
Achn121651bHLH family protein
Achn123541bHLH family protein
Achn125541bHLH family protein
Achn125991bHLH family protein
Achn126881bHLH family protein
Achn127411bHLH family protein
Achn128751bHLH family protein
Achn129161bHLH family protein
Achn136071bHLH family protein
Achn137551bHLH family protein
Achn138411bHLH family protein
Achn141461bHLH family protein
Achn143951bHLH family protein
Achn144111bHLH family protein
Achn146261bHLH family protein
Achn147751bHLH family protein
Achn147821bHLH family protein
Achn149871bHLH family protein
Achn154791bHLH family protein
Achn156931bHLH family protein
Achn157501bHLH family protein
Achn157701bHLH family protein
Achn158001bHLH family protein
Achn159461bHLH family protein
Achn159561bHLH family protein
Achn162841bHLH family protein
Achn165391bHLH family protein
Achn169871bHLH family protein
Achn171301bHLH family protein
Achn174051bHLH family protein
Achn174141bHLH family protein
Achn176631bHLH family protein
Achn177021bHLH family protein
Achn177031bHLH family protein
Achn177891bHLH family protein
Achn177941bHLH family protein
Achn178981bHLH family protein
Achn181261bHLH family protein
Achn182291bHLH family protein
Achn192881bHLH family protein
Achn204621bHLH family protein
Achn206741bHLH family protein
Achn207091bHLH family protein
Achn208591bHLH family protein
Achn211521bHLH family protein
Achn212861bHLH family protein
Achn215981bHLH family protein
Achn217751bHLH family protein
Achn217771bHLH family protein
Achn217961bHLH family protein
Achn221861bHLH family protein
Achn222131bHLH family protein
Achn222381bHLH family protein
Achn227371bHLH family protein
Achn229201bHLH family protein
Achn232701bHLH family protein
Achn233831bHLH family protein
Achn233841bHLH family protein
Achn234461bHLH family protein
Achn235091bHLH family protein
Achn238701bHLH family protein
Achn239761bHLH family protein
Achn239971bHLH family protein
Achn241401bHLH family protein
Achn243731bHLH family protein
Achn244201bHLH family protein
Achn244901bHLH family protein
Achn244921bHLH family protein
Achn247731bHLH family protein
Achn253521bHLH family protein
Achn253811bHLH family protein
Achn267831bHLH family protein
Achn270131bHLH family protein
Achn271221bHLH family protein
Achn271541bHLH family protein
Achn273391bHLH family protein
Achn281761bHLH family protein
Achn283551bHLH family protein
Achn292261bHLH family protein
Achn292881bHLH family protein
Achn293201bHLH family protein
Achn293221bHLH family protein
Achn299091bHLH family protein
Achn302211bHLH family protein
Achn309021bHLH family protein
Achn309341bHLH family protein
Achn310341bHLH family protein
Achn313111bHLH family protein
Achn313181bHLH family protein
Achn313661bHLH family protein
Achn317751bHLH family protein
Achn318391bHLH family protein
Achn321841bHLH family protein
Achn322811bHLH family protein
Achn326561bHLH family protein
Achn329601bHLH family protein
Achn329831bHLH family protein
Achn332351bHLH family protein
Achn333271bHLH family protein
Achn335591bHLH family protein
Achn336631bHLH family protein
Achn338911bHLH family protein
Achn338981bHLH family protein
Achn339261bHLH family protein
Achn344611bHLH family protein
Achn346301bHLH family protein
Achn346471bHLH family protein
Achn348381bHLH family protein
Achn348451bHLH family protein
Achn348741bHLH family protein
Achn348771bHLH family protein
Achn353411bHLH family protein
Achn354401bHLH family protein
Achn354411bHLH family protein
Achn354801bHLH family protein
Achn355681bHLH family protein
Achn357141bHLH family protein
Achn359461bHLH family protein
Achn359571bHLH family protein
Achn361761bHLH family protein
Achn361801bHLH family protein
Achn366021bHLH family protein
Achn367441bHLH family protein
Achn368981bHLH family protein
Achn374511bHLH family protein
Achn378861bHLH family protein
Achn379311bHLH family protein
Achn383051bHLH family protein
Achn389001bHLH 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