Gene Symbol: CONSTANS
Description: B-box type zinc finger protein with CCT domain-containing protein
Alias: B-box domain protein 1, BBX1, CONSTANS, F14F8.220, F14F8_220, B-box type zinc finger protein with CCT domain-containing protein
Species: thale cress

Top Publications

  1. Imaizumi T, Schultz T, Harmon F, Ho L, Kay S. FKF1 F-box protein mediates cyclic degradation of a repressor of CONSTANS in Arabidopsis. Science. 2005;309:293-7 pubmed
    The temporal control of CONSTANS (CO) expression and activity is a key mechanism in photoperiodic flowering in Arabidopsis...
  2. Tiwari S, Shen Y, Chang H, Hou Y, Harris A, Ma S, et al. The flowering time regulator CONSTANS is recruited to the FLOWERING LOCUS T promoter via a unique cis-element. New Phytol. 2010;187:57-66 pubmed publisher
    b>CONSTANS is an evolutionarily-conserved central component of the genetic pathway that controls the onset of flowering in response to daylength...
  3. Fornara F, Panigrahi K, Gissot L, Sauerbrunn N, Rühl M, Jarillo J, et al. Arabidopsis DOF transcription factors act redundantly to reduce CONSTANS expression and are essential for a photoperiodic flowering response. Dev Cell. 2009;17:75-86 pubmed publisher
    Flowering of Arabidopsis is induced by long summer days (LDs). The transcriptional regulator CONSTANS (CO) promotes flowering, and its transcription is increased under LDs...
  4. Laubinger S, Marchal V, Le Gourrierec J, Gentilhomme J, Wenkel S, Adrian J, et al. Arabidopsis SPA proteins regulate photoperiodic flowering and interact with the floral inducer CONSTANS to regulate its stability. Development. 2006;133:3213-22 pubmed
    ..Taken together, our results suggest, that SPA proteins regulate photoperiodic flowering by controlling the stability of the floral inducer CO. ..
  5. Song Y, Smith R, To B, Millar A, Imaizumi T. FKF1 conveys timing information for CONSTANS stabilization in photoperiodic flowering. Science. 2012;336:1045-9 pubmed publisher
    ..In Arabidopsis, the long day-specific expression of CONSTANS (CO) protein is crucial for flowering induction...
  6. Liu L, Zhang Y, Li Q, Sang Y, Mao J, Lian H, et al. COP1-mediated ubiquitination of CONSTANS is implicated in cryptochrome regulation of flowering in Arabidopsis. Plant Cell. 2008;20:292-306 pubmed publisher
    ..Under LDs, the transcription of FLOWERING LOCUS T (FT) is activated by CONSTANS (CO) in leaf, and the FT protein moves to the shoot apex to induce flowering...
  7. Mizoguchi T, Wright L, Fujiwara S, Cremer F, Lee K, Onouchi H, et al. Distinct roles of GIGANTEA in promoting flowering and regulating circadian rhythms in Arabidopsis. Plant Cell. 2005;17:2255-70 pubmed
    ..In Arabidopsis thaliana, a circadian clock-controlled flowering pathway comprising the genes GIGANTEA (GI), CONSTANS (CO), and FLOWERING LOCUS T (FT) promotes flowering specifically under long days...
  8. Morris K, Thornber S, Codrai L, Richardson C, Craig A, Sadanandom A, et al. DAY NEUTRAL FLOWERING represses CONSTANS to prevent Arabidopsis flowering early in short days. Plant Cell. 2010;22:1118-28 pubmed publisher
    The photoperiodic response in Arabidopsis thaliana requires the precise regulation of CONSTANS (CO) expression in relation to the light period during the day...
  9. Ito S, Song Y, Josephson Day A, Miller R, Breton G, Olmstead R, et al. FLOWERING BHLH transcriptional activators control expression of the photoperiodic flowering regulator CONSTANS in Arabidopsis. Proc Natl Acad Sci U S A. 2012;109:3582-7 pubmed publisher
    ..In Arabidopsis thaliana, transcriptional regulation of the CONSTANS (CO) gene and posttranslational regulation of CO protein are crucial mechanisms for proper day-length measurement ..

More Information


  1. Suárez López P, Wheatley K, Robson F, Onouchi H, Valverde F, Coupland G. CONSTANS mediates between the circadian clock and the control of flowering in Arabidopsis. Nature. 2001;410:1116-20 pubmed
    ..Here we show that expression of CONSTANS (CO), a gene that accelerates flowering in response to long days, is modulated by the circadian clock and day ..
  2. Wenkel S, Turck F, Singer K, Gissot L, Le Gourrierec J, Samach A, et al. CONSTANS and the CCAAT box binding complex share a functionally important domain and interact to regulate flowering of Arabidopsis. Plant Cell. 2006;18:2971-84 pubmed
    The CCT (for CONSTANS, CONSTANS-LIKE, TOC1) domain is found in 45 Arabidopsis thaliana proteins involved in processes such as photoperiodic flowering, light signaling, and regulation of circadian rhythms...
  3. Chen M, Ni M. RFI2, a RING-domain zinc finger protein, negatively regulates CONSTANS expression and photoperiodic flowering. Plant J. 2006;46:823-33 pubmed
    ..The interactions and subsequent signalling steps upstream of the flowering genes such as CONSTANS (CO) and FLOWERING LOCUS T (FT) remain largely unknown...
  4. Kim W, Hicks K, Somers D. Independent roles for EARLY FLOWERING 3 and ZEITLUPE in the control of circadian timing, hypocotyl length, and flowering time. Plant Physiol. 2005;139:1557-69 pubmed
    ..In contrast, ELF3 and ZTL overexpressors act similarly to control flowering time in long days through the CONSTANS/FLOWERING LOCUS T (CO/FT) pathway...
  5. Graeff M, Straub D, Eguen T, Dolde U, Rodrigues V, Brandt R, et al. MicroProtein-Mediated Recruitment of CONSTANS into a TOPLESS Trimeric Complex Represses Flowering in Arabidopsis. PLoS Genet. 2016;12:e1005959 pubmed publisher
    ..Here we show that two Arabidopsis thaliana microProteins, miP1a and miP1b, physically interact with CONSTANS (CO) a potent regulator of flowering time...
  6. Ando E, Ohnishi M, Wang Y, Matsushita T, Watanabe A, Hayashi Y, et al. TWIN SISTER OF FT, GIGANTEA, and CONSTANS have a positive but indirect effect on blue light-induced stomatal opening in Arabidopsis. Plant Physiol. 2013;162:1529-38 pubmed
    ..We show in Arabidopsis (Arabidopsis thaliana) that TWIN SISTER OF FT (TSF), CONSTANS (CO), and GIGANTEA (GI) provide a positive effect on stomatal opening...
  7. Rosas U, Mei Y, Xie Q, Banta J, Zhou R, Seufferheld G, et al. Variation in Arabidopsis flowering time associated with cis-regulatory variation in CONSTANS. Nat Commun. 2014;5:3651 pubmed publisher
    ..Here we identify and characterize natural variation in the cis-regulatory sequence in the transcription factor CONSTANS that underlies flowering time diversity in Arabidopsis...
  8. Castillejo C, Pelaz S. The balance between CONSTANS and TEMPRANILLO activities determines FT expression to trigger flowering. Curr Biol. 2008;18:1338-43 pubmed publisher
    ..We envision that this might be a general mechanism between long-day plants to ensure a tight regulation of flowering time. ..
  9. Iñigo S, Alvarez M, Strasser B, Califano A, Cerdán P. PFT1, the MED25 subunit of the plant Mediator complex, promotes flowering through CONSTANS dependent and independent mechanisms in Arabidopsis. Plant J. 2012;69:601-12 pubmed publisher
  10. Sjödin P, Hedman H, Shavorskaya O, Finet C, Lascoux M, Lagercrantz U. Recent degeneration of an old duplicated flowering time gene in Brassica nigra. Heredity (Edinb). 2007;98:375-84 pubmed
    ..Two copies of the flowering time gene CONSTANS (COa and COb) have been identified in B. nigra, and previous studies showed that COa is functional...
  11. Wang H, Pan J, Li Y, Lou D, Hu Y, Yu D. The DELLA-CONSTANS Transcription Factor Cascade Integrates Gibberellic Acid and Photoperiod Signaling to Regulate Flowering. Plant Physiol. 2016;172:479-88 pubmed publisher
    ..In this study, we found that GA-induced expression of FLOWERING LOCUS T (FT) under LDs was dependent on CONSTANS (CO), a critical transcription factor positively involved in photoperiod signaling...
  12. Song Y, Song N, Shin S, Kim H, Yun D, Lim C, et al. Isolation of CONSTANS as a TGA4/OBF4 interacting protein. Mol Cells. 2008;25:559-65 pubmed
    ..Here we present evidence for a novel function of OBF4 as a regulator of flowering. We identified CONSTANS (CO), a positive regulator of floral induction, as an OBF4-interacting protein, in a yeast two-hybrid library ..
  13. Nakamichi N, Kita M, Niinuma K, Ito S, Yamashino T, Mizoguchi T, et al. Arabidopsis clock-associated pseudo-response regulators PRR9, PRR7 and PRR5 coordinately and positively regulate flowering time through the canonical CONSTANS-dependent photoperiodic pathway. Plant Cell Physiol. 2007;48:822-32 pubmed
    ..In the long-day plant Arabidopsis thaliana, CONSTANS (CO) plays a crucial role in integrating the circadian rhythm and environmental light signals into the ..
  14. Gnesutta N, Kumimoto R, Swain S, Chiara M, Siriwardana C, Horner D, et al. CONSTANS Imparts DNA Sequence Specificity to the Histone Fold NF-YB/NF-YC Dimer. Plant Cell. 2017;29:1516-1532 pubmed publisher
    ..NF-YA shares a conserved domain with the CONSTANS, CONSTANS-LIKE, TOC1 (CCT) proteins...
  15. Kim S, Park H, Jang Y, Lee J, Kim J. The sequence variation responsible for the functional difference between the CONSTANS protein, and the CONSTANS-like (COL) 1 and COL2 proteins, resides mostly in the region encoded by their first exons. Plant Sci. 2013;199-200:71-8 pubmed publisher
    Although the protein CONSTANS (CO) and its close relatives CONSTANS-like (COL) 1 and COL2 exhibit high amino acid sequence similarities, only the CO protein regulates floral induction in Arabidopsis...
  16. Wollenberg A, Strasser B, Cerdán P, Amasino R. Acceleration of flowering during shade avoidance in Arabidopsis alters the balance between FLOWERING LOCUS C-mediated repression and photoperiodic induction of flowering. Plant Physiol. 2008;148:1681-94 pubmed publisher
    ..A low red to far-red ratio required the photoperiod-pathway genes GIGANTEA (GI) and CONSTANS (CO) to fully accelerate flowering in long days and did not promote flowering in short days...
  17. Kurup S, Jones H, Holdsworth M. Interactions of the developmental regulator ABI3 with proteins identified from developing Arabidopsis seeds. Plant J. 2000;21:143-55 pubmed
    ..All the AIPs show homology to existing transcription factors and therefore they may function with ABI3 within the network of transcriptional regulators that control embryo development in Arabidopsis. ..
  18. Sawa M, Kay S. [Molecular mechanism by which plant determines flowering timing with circadian clock]. Tanpakushitsu Kakusan Koso. 2008;53:739-46 pubmed
  19. Gil K, Park M, Lee H, Park Y, Han S, Kwon Y, et al. Alternative splicing provides a proactive mechanism for the diurnal CONSTANS dynamics in Arabidopsis photoperiodic flowering. Plant J. 2017;89:128-140 pubmed publisher
    The circadian clock control of CONSTANS (CO) transcription and the light-mediated stabilization of its encoded protein coordinately adjust photoperiodic flowering by triggering rhythmic expression of the floral integrator flowering locus ..
  20. Kang X, Zhou Y, Sun X, Ni M. HYPERSENSITIVE TO RED AND BLUE 1 and its C-terminal regulatory function control FLOWERING LOCUS T expression. Plant J. 2007;52:937-48 pubmed
    ..Overexpression of HRB1 did not affect the expression of the central clock oscillators, TOC1 and CCA1. HRB1 therefore represents a signaling step that regulates FT expression downstream of red and blue light perception. ..
  21. Endo M, Tanigawa Y, Murakami T, Araki T, Nagatani A. PHYTOCHROME-DEPENDENT LATE-FLOWERING accelerates flowering through physical interactions with phytochrome B and CONSTANS. Proc Natl Acad Sci U S A. 2013;110:18017-22 pubmed publisher
    ..cryptochrome 2; and flavin-binding, KELCH repeat, F-BOX 1, phyB delays flowering mainly by destabilizing the CONSTANS (CO) protein, whose reduction leads to decreased expression of a florigen gene, flowering locus T...
  22. Nguyen K, Park J, Park E, Lee I, Choi G. The Arabidopsis RING Domain Protein BOI Inhibits Flowering via CO-dependent and CO-independent Mechanisms. Mol Plant. 2015;8:1725-36 pubmed publisher
    ..BOIs repress the expression of FT by CONSTANS (CO)-dependent and -independent mechanisms: in the CO-dependent mechanism, BOIs bind to CO, inhibit the targeting ..
  23. Kang M, Yoo S, Kwon H, Lee B, Cho J, Noh Y, et al. Negative regulatory roles of DE-ETIOLATED1 in flowering time in Arabidopsis. Sci Rep. 2015;5:9728 pubmed publisher
    ..Thus, we propose that DET1 is a strong repressor of flowering and has a pivotal role in maintaining photoperiod sensitivity in the regulation of flowering time. ..
  24. Song Y, Estrada D, Johnson R, Kim S, Lee S, MacCoss M, et al. Distinct roles of FKF1, Gigantea, and Zeitlupe proteins in the regulation of Constans stability in Arabidopsis photoperiodic flowering. Proc Natl Acad Sci U S A. 2014;111:17672-7 pubmed publisher
    ..In Arabidopsis, the day-length-dependent regulation of Constans (CO) protein stability is crucial to induce flowering locus T (FT) expression for flowering in long days...
  25. Kubota A, Ito S, Shim J, Johnson R, Song Y, Breton G, et al. TCP4-dependent induction of CONSTANS transcription requires GIGANTEA in photoperiodic flowering in Arabidopsis. PLoS Genet. 2017;13:e1006856 pubmed publisher
    ..In Arabidopsis thaliana, CONSTANS (CO) transcription factor plays a central role in regulating photoperiodic flowering...
  26. Lazaro A, Valverde F, Piñeiro M, Jarillo J. The Arabidopsis E3 ubiquitin ligase HOS1 negatively regulates CONSTANS abundance in the photoperiodic control of flowering. Plant Cell. 2012;24:982-99 pubmed publisher
    ..The esd6/hos1 mutation causes decreased flowering locus C expression and requires CONSTANS (CO) protein for its early flowering phenotype under long days...
  27. Wang C, Guthrie C, Sarmast M, Dehesh K. BBX19 interacts with CONSTANS to repress FLOWERING LOCUS T transcription, defining a flowering time checkpoint in Arabidopsis. Plant Cell. 2014;26:3589-602 pubmed publisher
    ..expression of the Arabidopsis thaliana floral transition regulators FLOWERING LOCUS T (FT) and CONSTANS (CO) is antiphasic to that of BBX19, a transcription factor with two B-Box motifs...
  28. Zhang B, Wang L, Zeng L, Zhang C, Ma H. Arabidopsis TOE proteins convey a photoperiodic signal to antagonize CONSTANS and regulate flowering time. Genes Dev. 2015;29:975-87 pubmed publisher
    ..In Arabidopsis, CONSTANS (CO) and FLAVIN-BINDING KELCH REPEAT F-BOX1 (FKF1) promote flowering by inducing FLOWER LOCUS T (FT) expression ..
  29. Jung J, Seo P, Park C. The E3 ubiquitin ligase HOS1 regulates Arabidopsis flowering by mediating CONSTANS degradation under cold stress. J Biol Chem. 2012;287:43277-87 pubmed publisher
    ..Here, we report that intermittent cold treatments trigger the degradation of CONSTANS (CO), a central activator of photoperiodic flowering; daily treatments caused suppression of the floral ..
  30. Soppe W, Bentsink L, Koornneef M. The early-flowering mutant efs is involved in the autonomous promotion pathway of Arabidopsis thaliana. Development. 1999;126:4763-70 pubmed
    ..By comparing the length of the juvenile and adult phases of vegetative growth for wild-type, efs and the double mutant plants, it is apparent that efs mainly reduces the length of the adult phase. ..
  31. Xu F, Li T, Xu P, Li L, DU S, Lian H, et al. DELLA proteins physically interact with CONSTANS to regulate flowering under long days in Arabidopsis. FEBS Lett. 2016;590:541-9 pubmed publisher
    ..Here, we show through biochemical studies that DELLA proteins physically interact with CONSTANS (CO). Furthermore, the interaction of CO with NF-YB2 is inhibited by the DELLA protein, RGA...
  32. Hayama R, Sarid Krebs L, Richter R, Fernandez V, Jang S, Coupland G. PSEUDO RESPONSE REGULATORs stabilize CONSTANS protein to promote flowering in response to day length. EMBO J. 2017;36:904-918 pubmed publisher
    ..i>Arabidopsis thaliana promotes flowering in response to long days (LDs), and CONSTANS (CO) transcription factor represents a photoperiodic timer whose stability is higher when plants are exposed to ..
  33. Tseng T, Salome P, McClung C, Olszewski N. SPINDLY and GIGANTEA interact and act in Arabidopsis thaliana pathways involved in light responses, flowering, and rhythms in cotyledon movements. Plant Cell. 2004;16:1550-63 pubmed
    ..GI acts in the long-day flowering pathway upstream of CONSTANS (CO) and FLOWERING LOCUS T (FT). Loss of GI function causes late flowering and reduces CO and FT RNA levels...
  34. Sarid Krebs L, Panigrahi K, Fornara F, Takahashi Y, Hayama R, Jang S, et al. Phosphorylation of CONSTANS and its COP1-dependent degradation during photoperiodic flowering of Arabidopsis. Plant J. 2015;84:451-63 pubmed publisher
    Seasonal flowering involves responses to changes in day length. In Arabidopsis thaliana, the CONSTANS (CO) transcription factor promotes flowering in the long days of spring and summer...
  35. Kim S, Yu X, Michaels S. Regulation of CONSTANS and FLOWERING LOCUS T expression in response to changing light quality. Plant Physiol. 2008;148:269-79 pubmed publisher
    ..Previous work has shown that the floral promoter CONSTANS (CO) plays a critical role in day-length perception and exhibits complex regulation; CO mRNA is regulated by the ..
  36. Fukamatsu Y, Mitsui S, Yasuhara M, Tokioka Y, Ihara N, Fujita S, et al. Identification of LOV KELCH PROTEIN2 (LKP2)-interacting factors that can recruit LKP2 to nuclear bodies. Plant Cell Physiol. 2005;46:1340-9 pubmed
    ..Furthermore, the CFP-LKP2 and YFP-CO signals co-localized with signals for pU2B''-mRFP, which is a marker for Cajal bodies. These results suggest the possibility that LKP2 functions with CO/COL family proteins in the nuclear bodies. ..
  37. Ayre B, Turgeon R. Graft transmission of a floral stimulant derived from CONSTANS. Plant Physiol. 2004;135:2271-8 pubmed
    ..b>CONSTANS (CO) is implicated as a mediator between photoperiod perception and the transition to flowering in Arabidopsis...
  38. Liu Y, Liu Q, Yan Q, Shi L, Fang Y. Nucleolus-tethering system (NoTS) reveals that assembly of photobodies follows a self-organization model. Mol Biol Cell. 2014;25:1366-73 pubmed publisher
  39. Jang S, Marchal V, Panigrahi K, Wenkel S, Soppe W, Deng X, et al. Arabidopsis COP1 shapes the temporal pattern of CO accumulation conferring a photoperiodic flowering response. EMBO J. 2008;27:1277-88 pubmed publisher
    The transcriptional regulator CONSTANS (CO) promotes flowering of Arabidopsis under long summer days (LDs) but not under short winter days (SDs)...
  40. Kinmonth Schultz H, Tong X, Lee J, Song Y, Ito S, Kim S, et al. Cool night-time temperatures induce the expression of CONSTANS and FLOWERING LOCUS T to regulate flowering in Arabidopsis. New Phytol. 2016;211:208-24 pubmed publisher
    ..Cooler temperature treatments increased CONSTANS (CO) transcript levels at night. Night-time CO induction was diminished in flowering bhlh (fbh)-quadruple mutants...
  41. Hou X, Zhou J, Liu C, Liu L, Shen L, Yu H. Nuclear factor Y-mediated H3K27me3 demethylation of the SOC1 locus orchestrates flowering responses of Arabidopsis. Nat Commun. 2014;5:4601 pubmed publisher
    ..We show that NF-Y interacts with CONSTANS in the photoperiod pathway and DELLAs in the gibberellin pathway, to directly regulate the transcription of SOC1, ..
  42. Yoo S, Chung K, Kim J, Lee J, Hong S, Yoo S, et al. CONSTANS activates SUPPRESSOR OF OVEREXPRESSION OF CONSTANS 1 through FLOWERING LOCUS T to promote flowering in Arabidopsis. Plant Physiol. 2005;139:770-8 pubmed
    b>CONSTANS (CO) regulates flowering time by positively regulating expression of two floral integrators, FLOWERING LOCUS T (FT) and SUPPRESSOR OF OVEREXPRESSION OF CO 1 (SOC1), in Arabidopsis (Arabidopsis thaliana)...
  43. Zhu Y, Liu L, Shen L, Yu H. NaKR1 regulates long-distance movement of FLOWERING LOCUS T in Arabidopsis. Nat Plants. 2016;2:16075 pubmed publisher
    ..HMA) domain-containing protein, SODIUM POTASSIUM ROOT DEFECTIVE 1 (NaKR1), is activated by CONSTANS (CO) under long-day conditions and regulates long-distance movement of FT in Arabidopsis...
  44. Lazaro A, Mouriz A, Piñeiro M, Jarillo J. Red Light-Mediated Degradation of CONSTANS by the E3 Ubiquitin Ligase HOS1 Regulates Photoperiodic Flowering in Arabidopsis. Plant Cell. 2015;27:2437-54 pubmed publisher
    The regulation of CONSTANS (CO) gene expression is crucial to accurately measure changes in daylength, which influences flowering time in Arabidopsis thaliana...
  45. Bu Z, Yu Y, Li Z, Liu Y, Jiang W, Huang Y, et al. Regulation of arabidopsis flowering by the histone mark readers MRG1/2 via interaction with CONSTANS to modulate FT expression. PLoS Genet. 2014;10:e1004617 pubmed publisher
    ..In the model plant Arabidopsis thaliana, the transcription factor CONSTANS (CO) promotes expression of the florigen FLOWERING LOCUS T (FT), constituting a key flowering pathway under long-..
  46. Song Y, Lee I, Lee S, Imaizumi T, Hong J. CONSTANS and ASYMMETRIC LEAVES 1 complex is involved in the induction of FLOWERING LOCUS T in photoperiodic flowering in Arabidopsis. Plant J. 2012;69:332-42 pubmed publisher
    ..The day-length specific induction of FLOWERING LOCUS T (FT) regulated by CONSTANS (CO) is the crucial aspect of photoperiodic flowering in Arabidopsis thaliana...