Multiple bHLH Proteins form Heterodimers to Mediate CRY2-Dependent Regulation of Flowering-Time in

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Arabidopsis thaliana cryptochrome 2 (CRY2) mediates light control of flowering time. CIB1 (CRY2-interacting bHLH 1) specifically interacts with CRY2 in response to blue light to activate the transcription of FT (Flowering Locus T). In vitro, CIB1 binds to the canonical E-box (CACGTG, also referred to as G-box) with much higher affinity than its interaction with non-canonical E-box (CANNTG) DNA sequences. However, in vivo, CIB1 binds to the chromatin region of the FT promoter, which only contains the non-canonical E-box sequences. Here, we show that CRY2 also interacts with at least CIB5, in response to blue light, but not in darkness or in response to other wavelengths of light. Our genetic analysis demonstrates that CIB1, CIB2, CIB4, and CIB5 act redundantly to activate the transcription of FT and that they are positive regulators of CRY2 mediated flowering. More importantly, CIB1 and other CIBs proteins form heterodimers, and some of the heterodimers have a higher binding affinity than the CIB homodimers to the non-canonical E-box in the in vitro DNA-binding assays. This result explains why in vitro CIB1 and other CIBs bind to the canonical E-box (G-box) with a higher affinity, whereas they are all associated with the non-canonical E-boxes at the FT promoter in vivo. Consistent with the hypothesis that different CIB proteins play similar roles in the CRY2-midiated blue light signaling, the expression of CIB proteins is regulated specifically by blue light. Our study demonstrates that CIBs function redundantly in regulating CRY2-dependent flowering, and that different CIBs form heterodimers to interact with the non-canonical E-box DNA in vivo.

Vyšlo v časopise: Multiple bHLH Proteins form Heterodimers to Mediate CRY2-Dependent Regulation of Flowering-Time in. PLoS Genet 9(10): e32767. doi:10.1371/journal.pgen.1003861
Kategorie: Research Article
prolekare.web.journal.doi_sk: https://doi.org/10.1371/journal.pgen.1003861

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Zdroje

1. CashmoreAR (2003) Cryptochromes: enabling plants and animals to determine circadian time. Cell 114: 537–543.

2. SancarA (2003) Structure and function of DNA photolyase and cryptochrome blue-light photoreceptors. Chem Rev 103: 2203–2237.

3. LinC, ShalitinD (2003) Cryptochrome Structure and Signal transduction. Annu Rev Plant Biol 54: 469–496.

4. LiuH, LiuB, ZhaoC, PepperM, LinC (2011) The action mechanisms of plant cryptochromes. Trends Plant Sci 16: 684–691.

5. AhmadM, CashmoreAR (1993) HY4 gene of A. thaliana encodes a protein with characteristics of a blue-light photoreceptor. Nature 366: 162–166.

6. GuoH, YangH, MocklerTC, LinC (1998) Regulation of Flowering Time by Arabidopsis Photoreceptors. Science 279: 1360–1363.

7. ValverdeF, MouradovA, SoppeW, RavenscroftD, SamachA, et al. (2004) Photoreceptor regulation of CONSTANS protein in photoperiodic flowering. Science 303: 1003–1006.

8. YanovskyMJ, KaySA (2002) Molecular basis of seasonal time measurement in Arabidopsis. Nature 419: 308–312.

9. ZuoZ, LiuH, LiuB, LiuX, LinC (2011) Blue light-dependent interaction of CRY2 with SPA1 regulates COP1 activity and floral initiation in Arabidopsis. Curr Biol 21: 841–847.

10. SearleI, CouplandG (2004) Induction of flowering by seasonal changes in photoperiod. Embo J 23: 1217–1222.

11. CorbesierL, VincentC, JangS, FornaraF, FanQ, et al. (2007) FT protein movement contributes to long-distance signaling in floral induction of Arabidopsis. Science 316: 1030–1033.

12. LifschitzE, EviatarT, RozmanA, ShalitA, GoldshmidtA, et al. (2006) The tomato FT ortholog triggers systemic signals that regulate growth and flowering and substitute for diverse environmental stimuli. Proc Natl Acad Sci U S A 103: 6398–6403.

13. JangS, MarchalV, PanigrahiKC, WenkelS, SoppeW, et al. (2008) Arabidopsis COP1 shapes the temporal pattern of CO accumulation conferring a photoperiodic flowering response. Embo J 27: 1277–1288.

14. LiuH, YuX, LiK, KlejnotJ, YangH, et al. (2008) Photoexcited CRY2 interacts with CIB1 to regulate transcription and floral initiation in Arabidopsis. Science 322: 1535–1539.

15. SweereU, EichenbergK, LohrmannJ, Mira-RodadoV, BaurleI, et al. (2001) Interaction of the response regulator ARR4 with phytochrome B in modulating red light signaling. Science 294: 1108–1111.

16. NiM, TeppermanJM, QuailPH (1998) PIF3, a phytochrome-interacting factor necessary for normal photoinduced signal transduction, is a novel basic helix-loop-helix protein. Cell 95: 657–667.

17. HuqE, Al-SadyB, HudsonM, KimC, ApelK, et al. (2004) PHYTOCHROME-INTERACTING FACTOR 1 is a critical bHLH regulator of chlorophyll biosynthesis. Science 305: 1937–1941.

18. QuailPH (2002) Phytochrome photosensory signalling networks. Nat Rev Mol Cell Biol 3: 85–93.

19. Al-SadyB, KikisEA, MonteE, QuailPH (2008) Mechanistic duality of transcription factor function in phytochrome signaling. Proc Natl Acad Sci U S A 105: 2232–2237.

20. ChoiG, YiH, LeeJ, KwonY-K, SohMS, et al. (1999) Phytochrome signalling is mediated through nucleosidediphosphate kinase 2. Nature 401: 610–613.

21. RyuJS, KimJI, KunkelT, KimBC, ChoDS, et al. (2005) Phytochrome-specific type 5 phosphatase controls light signal flux by enhancing phytochrome stability and affinity for a signal transducer. Cell 120: 395–406.

22. NelsonDC, LasswellJ, RoggLE, CohenMA, BartelB (2000) FKF1, a clock-controlled gene that regulates the transition to flowering in Arabidopsis. Cell 101: 331–340.

23. SomersDE, SchultzTF, MilnamowM, KaySA (2000) ZEITLUPE encodes a novel clock-associated PAS protein from Arabidopsis. Cell 101: 319–329.

24. ImaizumiT, TranHG, SwartzTE, BriggsWR, KaySA (2003) FKF1 is essential for photoperiodic-specific light signalling in Arabidopsis. Nature 426: 302–306.

25. SawaM, NusinowDA, KaySA, ImaizumiT (2007) FKF1 and GIGANTEA complex formation is required for day-length measurement in Arabidopsis. Science 318: 261–265.

26. KimWY, FujiwaraS, SuhSS, KimJ, KimY, et al. (2007) ZEITLUPE is a circadian photoreceptor stabilized by GIGANTEA in blue light. Nature 449: 356–360.

27. Idevall-HagrenO, DicksonEJ, HilleB, ToomreDK, De CamilliP (2012) Optogenetic control of phosphoinositide metabolism. Proc Natl Acad Sci U S A 109: E2316–2323.

28. KennedyMJ, HughesRM, PeteyaLA, SchwartzJW, EhlersMD, et al. (2010) Rapid blue-light-mediated induction of protein interactions in living cells. Nat Methods 7: 973–975.

29. OhtaM, MatsuiK, HiratsuK, ShinshiH, Ohme-TakagiM (2001) Repression domains of class II ERF transcriptional repressors share an essential motif for active repression. Plant Cell 13: 1959–1968.

30. YuX, KlejnotJ, ZhaoX, ShalitinD, MaymonM, et al. (2007) Arabidopsis Cryptochrome 2 Completes Its Posttranslational Life Cycle in the Nucleus. Plant Cell 19: 3146–3156.

31. Bracha-DroriK, ShichrurK, KatzA, OlivaM, AngeloviciR, et al. (2004) Detection of protein-protein interactions in plants using bimolecular fluorescence complementation. Plant J 40: 419–427.

32. WalterM, ChabanC, SchutzeK, BatisticO, WeckermannK, et al. (2004) Visualization of protein interactions in living plant cells using bimolecular fluorescence complementation. Plant J 40: 428–438.

33. BaiMY, ZhangLY, GampalaSS, ZhuSW, SongWY, et al. (2007) Functions of OsBZR1 and 14-3-3 proteins in brassinosteroid signaling in rice. Proc Natl Acad Sci U S A 104: 13839–13844.

34. MocklerTC, YuX, ShalitinD, ParikhD, MichaelTP, et al. (2004) Regulation of flowering time in Arabidopsis by K homology domain proteins. Proc Natl Acad Sci U S A 101: 12759–12764.

35. HellensRP, AllanAC, FrielEN, BolithoK, GraftonK, et al. (2005) Transient expression vectors for functional genomics, quantification of promoter activity and RNA silencing in plants. Plant Methods 1: 13.

36. Toledo-OrtizG, HuqE, QuailPH (2003) The Arabidopsis basic/helix-loop-helix transcription factor family. Plant Cell 15: 1749–1770.

37. YuX, KlejnotJ, ZhaoX, ShalitinD, MaymonM, et al. (2007) Arabidopsis cryptochrome 2 completes its posttranslational life cycle in the nucleus. Plant Cell 19: 3146–3156.

38. CloughRC, Jordan-BeebeET, LohmanKN, maritaJM, WalkerJM, et al. (1999) Sequences within the N- and C-terminal domains of phytochrome A are required for PFR ubiquitination and degradation. Plant J 17: 155–167.

39. Al-SadyB, NiW, KircherS, SchaferE, QuailPH (2006) Photoactivated phytochrome induces rapid PIF3 phosphorylation prior to proteasome-mediated degradation. Mol Cell 23: 439–446.

40. LiuH, WangQ, LiuY, ImaizumiT, et al. (2013) The Arabidopsis photoreceptors CRY2 and ZTL mediate blue-light regulation of the transcription factor CIB1 by distinct mechanisms. Proc Natl Acad Sci U S A (in press).

41. SomersDE, DevlinPF, KaySA (1998) Phytochromes and cryptochromes in the entrainment of the Arabidopsis circadian clock. Science 282: 1488–1490.

42. FriedrichsenDM, NemhauserJ, MuramitsuT, MaloofJN, AlonsoJ, et al. (2002) Three redundant brassinosteroid early response genes encode putative bHLH transcription factors required for normal growth. Genetics 162: 1445–1456.

43. PoppenbergerB, RozhonW, KhanM, HusarS, AdamG, et al. (2011) CESTA, a positive regulator of brassinosteroid biosynthesis. EMBO J 30: 1149–1161.

44. VaraudE, BrioudesF, SzecsiJ, LerouxJ, BrownS, et al. (2011) AUXIN RESPONSE FACTOR8 regulates Arabidopsis petal growth by interacting with the bHLH transcription factor BIGPETALp. Plant Cell 23: 973–983.

45. IkedaM, FujiwaraS, MitsudaN, Ohme-TakagiM (2012) A triantagonistic basic helix-loop-helix system regulates cell elongation in Arabidopsis. Plant Cell 24: 4483–4497.

46. ZhangLY, BaiMY, WuJ, ZhuJY, WangH, et al. (2009) Antagonistic HLH/bHLH transcription factors mediate brassinosteroid regulation of cell elongation and plant development in rice and Arabidopsis. Plant Cell 21: 3767–3780.

47. BaiMY, FanM, OhE, WangZY (2013) A triple helix-loop-helix/basic helix-loop-helix cascade controls cell elongation downstream of multiple hormonal and environmental signaling pathways in Arabidopsis. Plant Cell 24: 4917–4929.

48. YoungMW, KaySA (2001) Time zones: a comparative genetics of circadian clocks. Nat Rev Genet 2: 702–715.

49. SancarA (2004) Regulation of mammalian circadian clock by cryptochrome. J Biol Chem 279: 34079–34082.

50. GirinT, PaicuT, StephensonP, FuentesS, KornerE, et al. (2011) INDEHISCENT and SPATULA interact to specify carpel and valve margin tissue and thus promote seed dispersal in Arabidopsis. Plant Cell 23: 3641–3653.

51. FairchildCD, SchumakerMA, QuailPH (2000) HFR1 encodes an atypical bHLH protein that acts in phytochrome A signal transduction. Genes Dev 14: 2377–2391.

52. HornitschekP, LorrainS, ZoeteV, MichielinO, FankhauserC (2009) Inhibition of the shade avoidance response by formation of non-DNA binding bHLH heterodimers. EMBO J 28: 3893–3902.

53. HongSY, SeoPJ, RyuJY, ChoSH, WooJC, et al. (2012) A competitive peptide inhibitor KIDARI negatively regulates HFR1 by forming nonfunctional heterodimers in Arabidopsis photomorphogenesis. Mol Cells 35: 25–31.

54. HaoY, OhE, ChoiG, LiangZ, WangZY (2012) Interactions between HLH and bHLH factors modulate light-regulated plant development. Mol Plant 5: 688–697.

55. GroveCA, De MasiF, BarrasaMI, NewburgerDE, AlkemaMJ, et al. (2009) A multiparameter network reveals extensive divergence between C. elegans bHLH transcription factors. Cell 138: 314–327.

56. YuX, SayeghR, MaymonM, WarpehaK, KlejnotJ, et al. (2009) Formation of nuclear bodies of Arabidopsis CRY2 in response to blue light is associated with its blue light-dependent degradation. Plant Cell 21: 118–130.

57. LiX, WangQ, YuX, LiuH, YangH, et al. (2011) Arabidopsis cryptochrome 2 (CRY2) functions by the photoactivation mechanism distinct from the tryptophan (trp) triad-dependent photoreduction. Proc Natl Acad Sci U S A 108: 20844–20849.

58. CloughS, BentAF (1998) Floral dip: a simple method for Agrobacterium-mediated transformation of Arabidopsis thaliana. Plant J 16: 735–743.

59. WeigelD, AhnJH, BlazquezMA, BorevitzJO, ChristensenSK, et al. (2000) Activation tagging in arabidopsis. Plant Physiol 122: 1003–1014.

60. KnowlesSM, LuS, TobinE (2008) Testing Time: can ethanol-induced pulses of proposed oscillator components phase shift rhythms in Arabidopsis? J Biol Rhythms In press.

61. KnowlesSM, LuSX, TobinEM (2008) Testing time: can ethanol-induced pulses of proposed oscillator components phase shift rhythms in Arabidopsis? J Biol Rhythms 23: 463–471.

62. YuX, ShalitinD, LiuX, MaymonM, KlejnotJ, et al. (2007) Derepression of the NC80 motif is critical for the photoactivation of Arabidopsis CRY2. Proc Natl Acad Sci U S A 104: 7289–7294.

63. JeffersonRA, KavanaghTA, bevanMW (1987) GUS fusions: β-glucoronidase as a sensitive and versatile gene fusion marker in higher plants. EMBO 6: 3901–3907.