Plant Transcription Factor Database
Previous version: v3.0
Transcription Factor Information
Basic Information | Signature Domain | Sequence | 
Basic Information? help Back to Top
TF ID AT4G09820.1
Common NameAtTT8, BHLH42, EN32, F17A8.170, TT8
Taxonomic ID
Taxonomic Lineage
cellular organisms; Eukaryota; Viridiplantae; Streptophyta; Streptophytina; Embryophyta; Tracheophyta; Euphyllophyta; Spermatophyta; Magnoliophyta; Mesangiospermae; eudicotyledons; Gunneridae; Pentapetalae; rosids; malvids; Brassicales; Brassicaceae; Camelineae; Arabidopsis
Family bHLH
Protein Properties Length: 518aa    MW: 59197.9 Da    PI: 5.6788
Description bHLH family protein
Gene Model
Gene Model ID Type Source Coding Sequence
AT4G09820.1genomeTAIRView CDS
Signature Domain? help Back to Top
Signature Domain
No. Domain Score E-value Start End HMM Start HMM End
          HLH   4 ahnerErrRRdriNsafeeLrellPkaskapskKlsKaeiLekAveYIksLq 55 
                  +h  +ErrRR+++N++f +Lr+++P       +K++K++iL  ++ Y+++L+
                  7999**********************8.....8*****************95 PP

Protein Features ? help Back to Top
3D Structure
Database Entry ID E-value Start End InterPro ID Description
PfamPF142156.5E-5520201IPR025610Transcription factor MYC/MYB N-terminal
PROSITE profilePS5088816.552359408IPR011598Myc-type, basic helix-loop-helix (bHLH) domain
SuperFamilySSF474591.44E-17362425IPR011598Myc-type, basic helix-loop-helix (bHLH) domain
CDDcd000836.17E-13362413No hitNo description
Gene3DG3DSA:, basic helix-loop-helix (bHLH) domain
PfamPF000101.2E-10363408IPR011598Myc-type, basic helix-loop-helix (bHLH) domain
SMARTSM003537.4E-17365414IPR011598Myc-type, basic helix-loop-helix (bHLH) domain
CDDcd021160.0099449509No hitNo description
Gene Ontology ? help Back to Top
GO Term GO Category GO Description
GO:0006355Biological Processregulation of transcription, DNA-templated
GO:0009962Biological Processregulation of flavonoid biosynthetic process
GO:0010026Biological Processtrichome differentiation
GO:0010214Biological Processseed coat development
GO:2000029Biological Processregulation of proanthocyanidin biosynthetic process
GO:0005634Cellular Componentnucleus
GO:0000976Molecular Functiontranscription regulatory region sequence-specific DNA binding
GO:0003700Molecular Functiontranscription factor activity, sequence-specific DNA binding
GO:0005515Molecular Functionprotein binding
GO:0046983Molecular Functionprotein dimerization activity
Plant Ontology ? help Back to Top
PO Term PO Category PO Description
PO:0000200anatomymicropylar endosperm
PO:0000293anatomyguard cell
PO:0001185developmental stageplant embryo globular stage
Sequence ? help Back to Top
Protein Sequence    Length: 518 aa     Download sequence    Send to blast
3D Structure ? help Back to Top
PDB ID Evalue Query Start Query End Hit Start Hit End Description
4rqw_A1e-211720110192Transcription factor MYC3
4rqw_B1e-211720110192Transcription factor MYC3
4rru_A3e-211718949219Transcription factor MYC3
4rs9_A1e-211720110192Transcription factor MYC3
4ywc_A3e-211718949219Transcription factor MYC3
4ywc_B3e-211718949219Transcription factor MYC3
4yz6_A1e-211720110192Transcription factor MYC3
Search in ModeBase
Nucleic Localization Signal ? help Back to Top
No. Start End Sequence
Expression -- UniGene ? help Back to Top
UniGene ID E-value Expressed in
At.101750.0flower| silique
Expression -- Microarray ? help Back to Top
Source ID E-value
Expression AtlasAT4G09820-
Expression -- Description ? help Back to Top
Source Description
UniprotDEVELOPMENTAL STAGE: Faint expression in buds and flowers. Increases during the very early stages of seed development, reaches a maximum at the globular embryo stage and stays high throughout seed formation.
UniprotTISSUE SPECIFICITY: Buds, flowers and developing siliques, but not in leaves, stems and roots. {ECO:0000269|PubMed:12679534}.
Functional Description ? help Back to Top
Source Description
TAIRTT8 is a regulation factor that acts in a concerted action with TT1, PAP1 and TTG1 on the regulation of flavonoid pathways, namely proanthocyanidin and anthocyanin biosynthesis. Affects dihydroflavonol 4-reductase gene expression. It is thought that a ternary complex composed of TT2, TT8 and TTG1 is necessary for correct expression of BAN in seed endothelium. Also important for important for marginal trichome development.
UniProtTranscription activator, when associated with MYB75/PAP1 or MYB90/PAP2. Involved in the control of flavonoid pigmentation. Plays a key role in regulating leucoanthocyanidin reductase (BANYULS) and dihydroflavonol-4-reductase (DFR). Not required for leucoanthocyanidin dioxygenase (LDOX) expression. {ECO:0000269|PubMed:15361138}.
Function -- GeneRIF ? help Back to Top
  1. TT8 expression is controlled by different combinations of MYB and bHLH factors in planta.
    [PMID: 16709193]
  2. Nitrogen regulation of anthocyanin biosynthesis in Arabidopsis thaliana red cells undergoes a mechanism by which nitrogen controls the expression of genes encoding both main components of the TTG1-GL3/TT8-PAP1 complex and negative regulators.
    [PMID: 22669605]
  3. These results provide a molecular model consistent with the specific and highly regulated expression of TT8.
    [PMID: 23398515]
  4. Proteolytic degradation of the flavonoid regulators, TRANSPARENT TESTA8 and TRANSPARENT TESTA GLABRA1, in Arabidopsis is mediated by the ubiquitin/26Sproteasome system
    [PMID: 23921543]
Cis-element ? help Back to Top
Regulation -- PlantRegMap ? help Back to Top
Source Upstream Regulator Target Gene
Regulation -- ATRM (Manually Curated Upstream Regulators) ? help Back to Top
Source Upstream Regulator (A: Activate/R: Repress)
ATRM AT1G56650 (A), AT1G63650 (A), AT1G71030 (R), AT3G49940 (R), AT4G09820 (A), AT4G37540 (R), AT5G35550 (A), AT5G41315 (A), AT5G67420 (R)
Regulation -- ATRM (Manually Curated Target Genes) ? help Back to Top
Source Target Gene (A: Activate/R: Repress)
ATRM AT1G61720(A), AT1G71030(A), AT1G79840(A), AT2G23550(A), AT2G23580(A), AT2G37260(A), AT4G09820(A), AT5G42800(A)
Interaction -- BIND ? help Back to Top
Source Intact With Description
BINDAT1G56650TT8 interacts with PAP1.
BINDAT1G66370TT8 interacts with MYB113.
BINDAT1G66380TT8 interacts with MYB114.
BINDAT1G66390TT8 interacts with PAP2.
BINDAT4G38620TT8 interacts with MYB4.
BINDAT5G35550TT8 interacts with TT2.
BINDAT5G52600TT8 interacts with MYB82.
Interaction ? help Back to Top
Source Intact With
BioGRIDAT4G38620, AT5G35550, AT1G56650, AT1G66370, AT1G66380, AT1G66390, AT1G79180
IntActSearch Q9FT81
Phenotype -- Mutation ? help Back to Top
Source ID
T-DNA ExpressAT4G09820
Annotation -- Nucleotide ? help Back to Top
Source Hit ID E-value Description
GenBankDQ4468130.0DQ446813.1 Arabidopsis thaliana clone pENTR221-At4g09820 basic helix-loop-helix family protein (At4g09820) mRNA, complete cds.
Annotation -- Protein ? help Back to Top
Source Hit ID E-value Description
RefseqNP_192720.20.0transcription factor TT8
SwissprotQ9FT810.0TT8_ARATH; Transcription factor TT8
TrEMBLD7LXD50.0D7LXD5_ARALL; Putative uncharacterized protein
STRINGAT4G09820.10.0(Arabidopsis thaliana)
Orthologous Group ? help Back to Top
LineageOrthologous Group IDTaxa NumberGene Number
Representative plantOGRP52261116
Publications ? help Back to Top
  1. Nesi N, et al.
    The TT8 gene encodes a basic helix-loop-helix domain protein required for expression of DFR and BAN genes in Arabidopsis siliques.
    Plant Cell, 2000. 12(10): p. 1863-78
  2. Riechmann JL, et al.
    Arabidopsis transcription factors: genome-wide comparative analysis among eukaryotes.
    Science, 2000. 290(5499): p. 2105-10
  3. Nesi N,Jond C,Debeaujon I,Caboche M,Lepiniec L
    The Arabidopsis TT2 gene encodes an R2R3 MYB domain protein that acts as a key determinant for proanthocyanidin accumulation in developing seed.
    Plant Cell, 2001. 13(9): p. 2099-114
  4. Abrahams S,Tanner GJ,Larkin PJ,Ashton AR
    Identification and biochemical characterization of mutants in the proanthocyanidin pathway in Arabidopsis.
    Plant Physiol., 2002. 130(2): p. 561-76
  5. Heim MA, et al.
    The basic helix-loop-helix transcription factor family in plants: a genome-wide study of protein structure and functional diversity.
    Mol. Biol. Evol., 2003. 20(5): p. 735-47
  6. Toledo-Ortiz G,Huq E,Quail PH
    The Arabidopsis basic/helix-loop-helix transcription factor family.
    Plant Cell, 2003. 15(8): p. 1749-70
  7. Zhang F,Gonzalez A,Zhao M,Payne CT,Lloyd A
    A network of redundant bHLH proteins functions in all TTG1-dependent pathways of Arabidopsis.
    Development, 2003. 130(20): p. 4859-69
  8. Baudry A, et al.
    TT2, TT8, and TTG1 synergistically specify the expression of BANYULS and proanthocyanidin biosynthesis in Arabidopsis thaliana.
    Plant J., 2004. 39(3): p. 366-80
  9. Zimmermann IM,Heim MA,Weisshaar B,Uhrig JF
    Comprehensive identification of Arabidopsis thaliana MYB transcription factors interacting with R/B-like BHLH proteins.
    Plant J., 2004. 40(1): p. 22-34
  10. Sharma SB,Dixon RA
    Metabolic engineering of proanthocyanidins by ectopic expression of transcription factors in Arabidopsis thaliana.
    Plant J., 2005. 44(1): p. 62-75
  11. Baudry A,Caboche M,Lepiniec L
    TT8 controls its own expression in a feedback regulation involving TTG1 and homologous MYB and bHLH factors, allowing a strong and cell-specific accumulation of flavonoids in Arabidopsis thaliana.
    Plant J., 2006. 46(5): p. 768-79
  12. Paolocci F, et al.
    Ectopic expression of a basic helix-loop-helix gene transactivates parallel pathways of proanthocyanidin biosynthesis. structure, expression analysis, and genetic control of leucoanthocyanidin 4-reductase and anthocyanidin reductase genes in Lotus corniculatus.
    Plant Physiol., 2007. 143(1): p. 504-16
  13. Underwood BA,Vanderhaeghen R,Whitford R,Town CD,Hilson P
    Simultaneous high-throughput recombinational cloning of open reading frames in closed and open configurations.
    Plant Biotechnol. J., 2006. 4(3): p. 317-24
  14. Berger B, et al.
    A simplified method for the analysis of transcription factor-promoter interactions that allows high-throughput data generation.
    Plant J., 2007. 50(5): p. 911-6
  15. Cominelli E, et al.
    Expression analysis of anthocyanin regulatory genes in response to different light qualities in Arabidopsis thaliana.
    J. Plant Physiol., 2008. 165(8): p. 886-94
  16. Ishida T, et al.
    Arabidopsis TRANSPARENT TESTA GLABRA2 is directly regulated by R2R3 MYB transcription factors and is involved in regulation of GLABRA2 transcription in epidermal differentiation.
    Plant Cell, 2007. 19(8): p. 2531-43
  17. Gonzalez A,Zhao M,Leavitt JM,Lloyd AM
    Regulation of the anthocyanin biosynthetic pathway by the TTG1/bHLH/Myb transcriptional complex in Arabidopsis seedlings.
    Plant J., 2008. 53(5): p. 814-27
  18. Yoshida K, et al.
    Functional differentiation of Lotus japonicus TT2s, R2R3-MYB transcription factors comprising a multigene family.
    Plant Cell Physiol., 2008. 49(2): p. 157-69
  19. Matsui K,Umemura Y,Ohme-Takagi M
    AtMYBL2, a protein with a single MYB domain, acts as a negative regulator of anthocyanin biosynthesis in Arabidopsis.
    Plant J., 2008. 55(6): p. 954-67
  20. Dubos C, et al.
    MYBL2 is a new regulator of flavonoid biosynthesis in Arabidopsis thaliana.
    Plant J., 2008. 55(6): p. 940-53
  21. Maes L,Inzé D,Goossens A
    Functional specialization of the TRANSPARENT TESTA GLABRA1 network allows differential hormonal control of laminal and marginal trichome initiation in Arabidopsis rosette leaves.
    Plant Physiol., 2008. 148(3): p. 1453-64
  22. Gonzalez A,Mendenhall J,Huo Y,Lloyd A
    TTG1 complex MYBs, MYB5 and TT2, control outer seed coat differentiation.
    Dev. Biol., 2009. 325(2): p. 412-21
  23. Buer CS,Djordjevic MA
    Architectural phenotypes in the transparent testa mutants of Arabidopsis thaliana.
    J. Exp. Bot., 2009. 60(3): p. 751-63
  24. Li SF, et al.
    The Arabidopsis MYB5 transcription factor regulates mucilage synthesis, seed coat development, and trichome morphogenesis.
    Plant Cell, 2009. 21(1): p. 72-89
  25. Nesi N, et al.
    The promoter of the Arabidopsis thaliana BAN gene is active in proanthocyanidin-accumulating cells of the Brassica napus seed coat.
    Plant Cell Rep., 2009. 28(4): p. 601-17
  26. Rowan DD, et al.
    Environmental regulation of leaf colour in red 35S:PAP1 Arabidopsis thaliana.
    New Phytol., 2009. 182(1): p. 102-15
  27. Arsovski AA,Villota MM,Rowland O,Subramaniam R,Western TL
    MUM ENHANCERS are important for seed coat mucilage production and mucilage secretory cell differentiation in Arabidopsis thaliana.
    J. Exp. Bot., 2009. 60(9): p. 2601-12
  28. Jiang Y,Yang B,Deyholos MK
    Functional characterization of the Arabidopsis bHLH92 transcription factor in abiotic stress.
    Mol. Genet. Genomics, 2009. 282(5): p. 503-16
  29. Rubin G,Tohge T,Matsuda F,Saito K,Scheible WR
    Members of the LBD family of transcription factors repress anthocyanin synthesis and affect additional nitrogen responses in Arabidopsis.
    Plant Cell, 2009. 21(11): p. 3567-84
  30. Brueggemann J,Weisshaar B,Sagasser M
    A WD40-repeat gene from Malus x domestica is a functional homologue of Arabidopsis thaliana TRANSPARENT TESTA GLABRA1.
    Plant Cell Rep., 2010. 29(3): p. 285-94
  31. Pattanaik S, et al.
    Isolation and functional characterization of a floral tissue-specific R2R3 MYB regulator from tobacco.
    Planta, 2010. 231(5): p. 1061-76
  32. Bhargava A,Mansfield SD,Hall HC,Douglas CJ,Ellis BE
    MYB75 functions in regulation of secondary cell wall formation in the Arabidopsis inflorescence stem.
    Plant Physiol., 2010. 154(3): p. 1428-38
  33. Jeong SW, et al.
    Ethylene suppression of sugar-induced anthocyanin pigmentation in Arabidopsis.
    Plant Physiol., 2010. 154(3): p. 1514-31
  34. Appelhagen I, et al.
    TRANSPARENT TESTA1 interacts with R2R3-MYB factors and affects early and late steps of flavonoid biosynthesis in the endothelium of Arabidopsis thaliana seeds.
    Plant J., 2011. 67(3): p. 406-19
  35. Appelhagen I, et al.
    Leucoanthocyanidin Dioxygenase in Arabidopsis thaliana: characterization of mutant alleles and regulation by MYB-BHLH-TTG1 transcription factor complexes.
    Gene, 2011. 484(1-2): p. 61-8
  36. Th
    A new system for fast and quantitative analysis of heterologous gene expression in plants.
    New Phytol., 2012. 193(2): p. 504-12
  37. Balkunde R,Bouyer D,H
    Nuclear trapping by GL3 controls intercellular transport and redistribution of TTG1 protein in Arabidopsis.
    Development, 2011. 138(22): p. 5039-48
  38. Chiu LW,Li L
    Characterization of the regulatory network of BoMYB2 in controlling anthocyanin biosynthesis in purple cauliflower.
    Planta, 2012. 236(4): p. 1153-64
  39. Zhou LL,Shi MZ,Xie DY
    Regulation of anthocyanin biosynthesis by nitrogen in TTG1-GL3/TT8-PAP1-programmed red cells of Arabidopsis thaliana.
    Planta, 2012. 236(3): p. 825-37
  40. Jia L, et al.
    Proanthocyanidins inhibit seed germination by maintaining a high level of abscisic acid in Arabidopsis thaliana.
    J Integr Plant Biol, 2012. 54(9): p. 663-73
  41. Schaart JG, et al.
    Identification and characterization of MYB-bHLH-WD40 regulatory complexes controlling proanthocyanidin biosynthesis in strawberry (Fragaria
    New Phytol., 2013. 197(2): p. 454-67
  42. Xu W, et al.
    Regulation of flavonoid biosynthesis involves an unexpected complex transcriptional regulation of TT8 expression, in Arabidopsis.
    New Phytol., 2013. 198(1): p. 59-70
  43. Efroni I, et al.
    Regulation of leaf maturation by chromatin-mediated modulation of cytokinin responses.
    Dev. Cell, 2013. 24(4): p. 438-45
  44. Qi T,Song S,Xie D
    Modified bimolecular fluorescence complementation assay to study the inhibition of transcription complex formation by JAZ proteins.
    Methods Mol. Biol., 2013. 1011: p. 187-97
  45. Patra B,Pattanaik S,Yuan L
    Proteolytic degradation of the flavonoid regulators, TRANSPARENT TESTA8 and TRANSPARENT TESTA GLABRA1, in Arabidopsis is mediated by the ubiquitin/26Sproteasome system.
    Plant Signal Behav, 2013. 8(10): p. doi: 10.4161/psb.25901
  46. Chen M, et al.
    TRANSPARENT TESTA8 Inhibits Seed Fatty Acid Accumulation by Targeting Several Seed Development Regulators in Arabidopsis.
    Plant Physiol., 2014. 165(2): p. 905-916
  47. Jin J, et al.
    An Arabidopsis Transcriptional Regulatory Map Reveals Distinct Functional and Evolutionary Features of Novel Transcription Factors.
    Mol. Biol. Evol., 2015. 32(7): p. 1767-73
  48. Shirley BW, et al.
    Analysis of Arabidopsis mutants deficient in flavonoid biosynthesis.
    Plant J., 1995. 8(5): p. 659-71
  49. Pelletier MK,Shirley BW
    Analysis of flavanone 3-hydroxylase in Arabidopsis seedlings. Coordinate regulation with chalcone synthase and chalcone isomerase.
    Plant Physiol., 1996. 111(1): p. 339-45
  50. Bell-Lelong DA,Cusumano JC,Meyer K,Chapple C
    Cinnamate-4-hydroxylase expression in Arabidopsis. Regulation in response to development and the environment.
    Plant Physiol., 1997. 113(3): p. 729-38
  51. Pelletier MK,Murrell JR,Shirley BW
    Characterization of flavonol synthase and leucoanthocyanidin dioxygenase genes in Arabidopsis. Further evidence for differential regulation of "early" and "late" genes.
    Plant Physiol., 1997. 113(4): p. 1437-45