PlantTFDB
Plant Transcription Factor Database
v4.0
Previous version: v1.0, v2.0, v3.0
Amaranthus hypochondriacus
bHLH Family
Species TF ID Description
AHYPO_000106-RAbHLH family protein
AHYPO_000115-RAbHLH family protein
AHYPO_000421-RAbHLH family protein
AHYPO_000424-RAbHLH family protein
AHYPO_000515-RAbHLH family protein
AHYPO_000754-RAbHLH family protein
AHYPO_000961-RAbHLH family protein
AHYPO_001120-RAbHLH family protein
AHYPO_001473-RAbHLH family protein
AHYPO_001524-RAbHLH family protein
AHYPO_001902-RAbHLH family protein
AHYPO_002198-RAbHLH family protein
AHYPO_002238-RAbHLH family protein
AHYPO_002318-RAbHLH family protein
AHYPO_002424-RAbHLH family protein
AHYPO_002586-RAbHLH family protein
AHYPO_002761-RAbHLH family protein
AHYPO_002930-RAbHLH family protein
AHYPO_003060-RAbHLH family protein
AHYPO_003219-RAbHLH family protein
AHYPO_003471-RAbHLH family protein
AHYPO_003478-RAbHLH family protein
AHYPO_003548-RAbHLH family protein
AHYPO_004081-RAbHLH family protein
AHYPO_004220-RAbHLH family protein
AHYPO_004287-RAbHLH family protein
AHYPO_004439-RAbHLH family protein
AHYPO_004632-RAbHLH family protein
AHYPO_005185-RAbHLH family protein
AHYPO_005427-RAbHLH family protein
AHYPO_005430-RAbHLH family protein
AHYPO_005581-RAbHLH family protein
AHYPO_005710-RAbHLH family protein
AHYPO_005804-RAbHLH family protein
AHYPO_005915-RAbHLH family protein
AHYPO_005942-RAbHLH family protein
AHYPO_006057-RAbHLH family protein
AHYPO_006113-RAbHLH family protein
AHYPO_006114-RAbHLH family protein
AHYPO_006115-RAbHLH family protein
AHYPO_006116-RAbHLH family protein
AHYPO_006211-RAbHLH family protein
AHYPO_006212-RAbHLH family protein
AHYPO_006213-RAbHLH family protein
AHYPO_006527-RAbHLH family protein
AHYPO_006651-RAbHLH family protein
AHYPO_006734-RAbHLH family protein
AHYPO_006754-RAbHLH family protein
AHYPO_007243-RAbHLH family protein
AHYPO_007427-RAbHLH family protein
AHYPO_007723-RAbHLH family protein
AHYPO_008088-RAbHLH family protein
AHYPO_008862-RAbHLH family protein
AHYPO_008864-RAbHLH family protein
AHYPO_008906-RAbHLH family protein
AHYPO_008979-RAbHLH family protein
AHYPO_008986-RAbHLH family protein
AHYPO_009054-RAbHLH family protein
AHYPO_009950-RAbHLH family protein
AHYPO_010177-RAbHLH family protein
AHYPO_010179-RAbHLH family protein
AHYPO_010395-RAbHLH family protein
AHYPO_010636-RAbHLH family protein
AHYPO_010752-RAbHLH family protein
AHYPO_010754-RAbHLH family protein
AHYPO_011111-RAbHLH family protein
AHYPO_011550-RAbHLH family protein
AHYPO_011622-RAbHLH family protein
AHYPO_011750-RAbHLH family protein
AHYPO_012611-RAbHLH family protein
AHYPO_012613-RAbHLH family protein
AHYPO_012706-RAbHLH family protein
AHYPO_012779-RAbHLH family protein
AHYPO_012796-RAbHLH family protein
AHYPO_012860-RAbHLH family protein
AHYPO_013017-RAbHLH family protein
AHYPO_013130-RAbHLH family protein
AHYPO_013291-RAbHLH family protein
AHYPO_013352-RAbHLH family protein
AHYPO_013589-RAbHLH family protein
AHYPO_013629-RAbHLH family protein
AHYPO_013681-RAbHLH family protein
AHYPO_014722-RAbHLH family protein
AHYPO_015570-RAbHLH family protein
AHYPO_015574-RAbHLH family protein
AHYPO_015818-RAbHLH family protein
AHYPO_015877-RAbHLH family protein
AHYPO_015983-RAbHLH family protein
AHYPO_015986-RAbHLH family protein
AHYPO_016011-RAbHLH family protein
AHYPO_016212-RAbHLH family protein
AHYPO_016315-RAbHLH family protein
AHYPO_016495-RAbHLH family protein
AHYPO_016574-RAbHLH family protein
AHYPO_016575-RAbHLH family protein
AHYPO_017050-RAbHLH family protein
AHYPO_017472-RAbHLH family protein
AHYPO_017737-RAbHLH family protein
AHYPO_018100-RAbHLH family protein
AHYPO_018244-RAbHLH family protein
AHYPO_018868-RAbHLH family protein
AHYPO_018938-RAbHLH family protein
AHYPO_018954-RAbHLH family protein
AHYPO_018973-RAbHLH family protein
AHYPO_019044-RAbHLH family protein
AHYPO_019315-RAbHLH family protein
AHYPO_019438-RAbHLH family protein
AHYPO_019632-RAbHLH family protein
AHYPO_019672-RAbHLH family protein
AHYPO_019684-RAbHLH family protein
AHYPO_019832-RAbHLH family protein
AHYPO_019834-RAbHLH family protein
AHYPO_019920-RAbHLH family protein
AHYPO_020351-RAbHLH family protein
AHYPO_020436-RAbHLH family protein
AHYPO_020654-RAbHLH family protein
AHYPO_020770-RAbHLH family protein
AHYPO_021203-RAbHLH family protein
AHYPO_021418-RAbHLH family protein
AHYPO_021965-RAbHLH 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