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Negative feedback regulation of UV-B-induced photomorphogenesis and stress acclimation in Arabidopsis

Gruber, Henriette
Heller, Werner
Albert, Andreas
Seidlitz, Harald K
Published in Proceedings of the National Academy of Sciences. 2010, vol. 107, no. 46, p. 20132-20137
Abstract Plants respond to low levels of UV-B radiation with a coordinated photomorphogenic response that allows acclimation to this environmental stress factor. The key players in this UV-B response are COP1 (an E3 ubiquitin ligase), UVR8 (a β-propeller protein), and HY5 (a bZIP transcription factor). We have shown previously that an elevated UV-B-specific response is associated with dwarf growth, indicating the importance of balancing UV-B-specific signaling. Negative regulators of this pathway are not known, however. Here, we describe two highly related WD40-repeat proteins, REPRESSOR OF UV-B PHOTOMORPHOGENESIS 1 (RUP1) and RUP2, that interact directly with UVR8 as potent repressors of UV-B signaling. Both genes were transcriptionally activated by UV-B in a COP1-, UVR8-, and HY5-dependent manner. rup1 rup2 double mutants showed an enhanced response to UV-B and elevated UV-B tolerance after acclimation. Overexpression of RUP2 resulted in reduced UV-B-induced photomorphogenesis and impaired acclimation, leading to hypersensitivity to UV-B stress. These results are consistent with an important regulatory role for RUP1 and RUP2, which act downstream of UVR8-COP1 in a negative feedback loop impinging on UVR8 function, balancing UV-B defense measures and plant growth.
Keywords Acclimatization/radiation effectsArabidopsis/growth & development/radiation effectsArabidopsis Proteins/genetics/metabolismFeedback, Physiological/radiation effectsGene Expression Regulation, Plant/radiation effectsMorphogenesis/radiation effectsMutation/geneticsProtein Binding/radiation effectsRNA, Messenger/genetics/metabolismSignal Transduction/radiation effectsStress, Physiological/radiation effectsUltraviolet Rays
PMID: 21041653
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Other version: http://www.pnas.org/content/107/46/20132.long
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GRUBER, Henriette et al. Negative feedback regulation of UV-B-induced photomorphogenesis and stress acclimation in Arabidopsis. In: Proceedings of the National Academy of Sciences, 2010, vol. 107, n° 46, p. 20132-20137. https://archive-ouverte.unige.ch/unige:19311

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Deposited on : 2012-03-30

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