PlantTFDB
Plant Transcription Factor Database
v4.0
Previous version: v1.0, v2.0, v3.0
Spinacia oleracea
bHLH Family
Species TF ID Description
Sp_000340_siic.t1bHLH family protein
Sp_003020_mejr.t1bHLH family protein
Sp_008660_oskq.t1bHLH family protein
Sp_008660_oskq.t2bHLH family protein
Sp_008660_oskq.t3bHLH family protein
Sp_012370_kzrr.t1bHLH family protein
Sp_015210_zrxi.t1bHLH family protein
Sp_015250_agko.t1bHLH family protein
Sp_015250_agko.t2bHLH family protein
Sp_015990_inss.t1bHLH family protein
Sp_017560_cwtt.t1bHLH family protein
Sp_018030_yjcc.t1bHLH family protein
Sp_023740_theh.t1bHLH family protein
Sp_024910_nchh.t1bHLH family protein
Sp_026020_gcng.t1bHLH family protein
Sp_026020_gcng.t2bHLH family protein
Sp_032720_pyix.t1bHLH family protein
Sp_033280_ssaz.t1bHLH family protein
Sp_033280_ssaz.t2bHLH family protein
Sp_035090_mwct.t1bHLH family protein
Sp_038470_dfya.t1bHLH family protein
Sp_038480_mosn.t1bHLH family protein
Sp_039500_miqj.t1bHLH family protein
Sp_041130_hpja.t1bHLH family protein
Sp_041130_hpja.t2bHLH family protein
Sp_041430_wwou.t1bHLH family protein
Sp_041430_wwou.t2bHLH family protein
Sp_041430_wwou.t3bHLH family protein
Sp_042400_oxwq.t1bHLH family protein
Sp_045300_rgzh.t1bHLH family protein
Sp_046870_gztn.t1bHLH family protein
Sp_048610_cqij.t1bHLH family protein
Sp_048620_tqpy.t1bHLH family protein
Sp_049120_hoyq.t1bHLH family protein
Sp_049120_hoyq.t2bHLH family protein
Sp_052800_gxnr.t1bHLH family protein
Sp_052800_gxnr.t2bHLH family protein
Sp_055290_kwui.t1bHLH family protein
Sp_060680_phqp.t1bHLH family protein
Sp_060870_ayep.t1bHLH family protein
Sp_060870_ayep.t2bHLH family protein
Sp_067200_ccqz.t1bHLH family protein
Sp_068120_ctqx.t1bHLH family protein
Sp_069720_rxjt.t1bHLH family protein
Sp_069780_ywkn.t1bHLH family protein
Sp_071590_rodk.t1bHLH family protein
Sp_076120_jsgg.t1bHLH family protein
Sp_079400_kktc.t1bHLH family protein
Sp_079400_kktc.t2bHLH family protein
Sp_079960_puqw.t1bHLH family protein
Sp_081750_ryox.t1bHLH family protein
Sp_083610_stuc.t1bHLH family protein
Sp_089090_qymp.t1bHLH family protein
Sp_092940_qpgn.t1bHLH family protein
Sp_099340_ijoz.t1bHLH family protein
Sp_103210_nzsd.t1bHLH family protein
Sp_104590_rnkq.t1bHLH family protein
Sp_104590_rnkq.t2bHLH family protein
Sp_105690_ioxf.t1bHLH family protein
Sp_111270_hwee.t1bHLH family protein
Sp_111390_dnnq.t1bHLH family protein
Sp_111390_dnnq.t2bHLH family protein
Sp_112930_fado.t1bHLH family protein
Sp_113870_nrai.t1bHLH family protein
Sp_118730_ygxz.t1bHLH family protein
Sp_118740_hmni.t1bHLH family protein
Sp_119480_cxqc.t1bHLH family protein
Sp_119480_cxqc.t2bHLH family protein
Sp_120700_aoao.t1bHLH family protein
Sp_120700_aoao.t2bHLH family protein
Sp_120700_aoao.t3bHLH family protein
Sp_121000_ftug.t1bHLH family protein
Sp_121780_ueai.t1bHLH family protein
Sp_137650_ogcn.t1bHLH family protein
Sp_137990_dqfz.t1bHLH family protein
Sp_139450_ckez.t1bHLH family protein
Sp_140850_fpsh.t1bHLH family protein
Sp_143900_sark.t1bHLH family protein
Sp_143930_utat.t1bHLH family protein
Sp_145330_hqsi.t1bHLH family protein
Sp_147650_hjcs.t1bHLH family protein
Sp_149800_prfg.t1bHLH family protein
Sp_149970_ueye.t1bHLH family protein
Sp_155000_eooz.t1bHLH family protein
Sp_156440_psht.t1bHLH family protein
Sp_156440_psht.t2bHLH family protein
Sp_157670_ouaa.t1bHLH family protein
Sp_158840_zjzt.t1bHLH family protein
Sp_159490_wski.t1bHLH family protein
Sp_159770_euox.t1bHLH family protein
Sp_159790_wkoi.t1bHLH family protein
Sp_160820_yjqt.t1bHLH family protein
Sp_165360_pyos.t1bHLH family protein
Sp_167700_kkgk.t1bHLH family protein
Sp_172560_ejse.t1bHLH family protein
Sp_174090_kgtk.t1bHLH family protein
Sp_184400_kmji.t1bHLH family protein
Sp_184570_nqgn.t1bHLH family protein
Sp_192690_agzp.t1bHLH family protein
Sp_196050_qian.t1bHLH family protein
Sp_197080_wmsc.t1bHLH family protein
Sp_198490_ydyh.t1bHLH family protein
Sp_199490_ehdm.t1bHLH family protein
Sp_204350_kxxj.t1bHLH family protein
Sp_204520_eoji.t1bHLH family protein
Sp_211310_gisw.t1bHLH family protein
Sp_211310_gisw.t2bHLH family protein
Sp_212030_dnsd.t1bHLH family protein
Sp_212040_dcah.t1bHLH family protein
Sp_213250_jxkz.t1bHLH family protein
Sp_215520_cazh.t1bHLH 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