Conversion from CUL4-based COP1–SPA E3 apparatus to UVR8–COP1–SPA complexes underlies a distinct biochemical function of COP1 under UV-B

Huang, Xi; Ouyang, Xinhao; Yang, Po; Lau, On Sun; Chen, Liangbi; Wei, Ning; Deng, Xing Wang

doi:10.1073/pnas.1316622110

Cited by 171 publications

(205 citation statements)

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“…These dilemmas are not specific to the results for HY5 but represent general uncertainties when interpreting ChIP data. In addition, it is yet uncertain whether the UV-Binduced HY5 association with chromatin of target genes primarily reflects the stabilization of the HY5 protein (Favory et al, 2009;Huang et al, 2013) or the activity of the HY5 protein is affected otherwise by UV-B. It was previously reported that phosphorylation of HY5 within its COP1 binding domain may regulate HY5 stability and activity .…”

Section: Regulation Of the Hy5 Association With Chromatinmentioning

confidence: 99%

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UV-B-Responsive Association of the Arabidopsis bZIP Transcription Factor ELONGATED HYPOCOTYL5 with Target Genes, Including Its Own Promoter

et al. 2014

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In plants subjected to UV-B radiation, responses are activated that minimize damage caused by UV-B. The bZIP transcription factor ELONGATED HYPOCOTYL5 (HY5) acts downstream of the UV-B photoreceptor UV RESISTANCE LOCUS8 (UVR8) and promotes UV-B-induced photomorphogenesis and acclimation. Expression of HY5 is induced by UV-B; however, the transcription factor(s) that regulate HY5 transcription in response to UV-B and the impact of UV-B on the association of HY5 with its target promoters are currently unclear. Here, we show that HY5 binding to the promoters of UV-B-responsive genes is enhanced by UV-B in a UVR8-dependent manner in Arabidopsis thaliana. In agreement, overexpression of REPRESSOR OF UV-B PHOTOMORPHOGENESIS2, a negative regulator of UVR8 function, blocks UV-B-responsive HY5 enrichment at target promoters. Moreover, we have identified a T/G-box in the HY5 promoter that is required for its UV-B responsiveness. We show that HY5 and its homolog HYH bind to the T/G HY5 -box cis-acting element and that they act redundantly in the induction of HY5 expression upon UV-B exposure. Therefore, HY5 is enriched at target promoters in response to UV-B in a UVR8 photoreceptor-dependent manner, and HY5 and HYH interact directly with a T/G-box cis-acting element of the HY5 promoter, mediating the transcriptional activation of HY5 in response to UV-B.

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Section: Regulation Of the Hy5 Association With Chromatinmentioning

confidence: 99%

“…HY5 itself, as well as HYH, is one of the UVR8-and COP1-regulated genes (Brown et al, 2005;Oravecz et al, 2006;Favory et al, 2009), but the transcription factor(s) and cis-regulatory element(s) mediating its transcription are not known. HY5 is also known to be posttranslationally stabilized by UV-B (Favory et al, 2009;Huang et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

UV-B-Responsive Association of the Arabidopsis bZIP Transcription Factor ELONGATED HYPOCOTYL5 with Target Genes, Including Its Own Promoter

et al. 2014

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“…Upon perception of UV-B light, UVR8 is activated by undergoing a dimer-to-monomer conformational change (5)(6)(7). The monomerization of UVR8 allows it to associate with the tetrameric constitutively photomorphogenic 1-suppressor of PHYA (COP1-SPA) core complex (8). This association, in turn, drives the release of COP1-SPA from the cullin 4-damaged DNA-binding protein 1 (CUL4-DDB1) E3 apparatus that represses light signaling under various light conditions (8,9).…”

mentioning

confidence: 99%

“…The monomerization of UVR8 allows it to associate with the tetrameric constitutively photomorphogenic 1-suppressor of PHYA (COP1-SPA) core complex (8). This association, in turn, drives the release of COP1-SPA from the cullin 4-damaged DNA-binding protein 1 (CUL4-DDB1) E3 apparatus that represses light signaling under various light conditions (8,9). The UV-B-dependent UVR8-COP1-SPA complex then acts as a molecular switch to turn on downstream signaling, including positively modulating the stability and activity of a central photomorphogenesis-promoting transcription factor, elongated hypocotyl 5 (HY5) (8).…”

mentioning

confidence: 99%

“…This association, in turn, drives the release of COP1-SPA from the cullin 4-damaged DNA-binding protein 1 (CUL4-DDB1) E3 apparatus that represses light signaling under various light conditions (8,9). The UV-B-dependent UVR8-COP1-SPA complex then acts as a molecular switch to turn on downstream signaling, including positively modulating the stability and activity of a central photomorphogenesis-promoting transcription factor, elongated hypocotyl 5 (HY5) (8). As a feedback response, HY5 activates the COP1 transcription, whereas another transcription factor, far-red elongated hypocotyl 3 (FHY3), functions genetically upstream of both COP1 and HY5 to directly activate COP1 (10).…”

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confidence: 99%

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Coordinated photomorphogenic UV-B signaling network captured by mathematical modeling

Ouyang

Huang

Xiao

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

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Long-wavelength and low-fluence UV-B light is an informational signal known to induce photomorphogenic development in plants. Using the model plant Arabidopsis thaliana, a variety of factors involved in UV-B-specific signaling have been experimentally characterized over the past decade, including the UV-B light receptor UV resistance locus 8; the positive regulators constitutive photomorphogenesis 1 and elongated hypocotyl 5; and the negative regulators cullin4, repressor of UV-B photomorphogenesis 1 (RUP1), and RUP2. Individual genetic and molecular studies have revealed that these proteins function in either positive or negative regulatory capacities for the sufficient and balanced transduction of photomorphogenic UV-B signal. Less is known, however, regarding how these signaling events are systematically linked. In our study, we use a systems biology approach to investigate the dynamic behaviors and correlations of multiple signaling components involved in Arabidopsis UV-B-induced photomorphogenesis. We define a mathematical representation of photomorphogenic UV-B signaling at a temporal scale. Supplemented with experimental validation, our computational modeling demonstrates the functional interaction that occurs among different protein complexes in early and prolonged response to photomorphogenic UV-B.light signaling | ordinary differential equation

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Plant Light Stress

Pascual

Rahikainen

Kangasjärvi

2017

Encyclopedia of Life Sciences

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Photosynthesis forms the basis for primary production and fuels the formation of biomass with valuable chemical composition in plants. Although photosynthesis requires sunlight, the very nature of sunlight also has negative effects on photosynthesis. Visible light and ultraviolet light, the inherent parts of sunlight, may cause damage to the photosynthetic machinery and other cellular components. Plants have therefore evolved various protective and response mechanisms, which monitor the intensity, wavelength, duration and direction of light and mitigate the negative effects of light stress. Currently, the underlying molecular mechanisms and functional overlaps among light receptor and chloroplast signalling, and the consequent light‐dependent adjustments in plant performance are emerging. The ability to delicately sense, signal and respond to the ambient light environment forms a key contributor to plant growth and productivity. Key Concepts Photosynthesis causes a potential risk of photodamage. Excess light and ultraviolet radiation from sunlight lead to increased production of ROS, which may cause photooxidative damage. Plants have evolved protective and response mechanisms against photodamage. ROS act as signalling molecules that mediate vital functions in inducing resistance to light stress and other abiotic and biotic stresses. Chloroplast retrograde signals play key roles in eliciting cross‐tolerance to biotic stress factors.

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Conversion from CUL4-based COP1–SPA E3 apparatus to UVR8–COP1–SPA complexes underlies a distinct biochemical function of COP1 under UV-B

Cited by 171 publications

References 27 publications

UV-B-Responsive Association of the Arabidopsis bZIP Transcription Factor ELONGATED HYPOCOTYL5 with Target Genes, Including Its Own Promoter

UV-B-Responsive Association of the Arabidopsis bZIP Transcription Factor ELONGATED HYPOCOTYL5 with Target Genes, Including Its Own Promoter

Coordinated photomorphogenic UV-B signaling network captured by mathematical modeling

Plant Light Stress

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