HYPERSENSITIVE TO RED AND BLUE 1, a ZZ-Type Zinc Finger Protein, Regulates Phytochrome B–Mediated Red and Cryptochrome-Mediated Blue Light Responses

Kang, Xiaojun; Chong, Jason; Ni, Min

doi:10.1105/tpc.104.029165

Cited by 52 publications

(68 citation statements)

References 53 publications

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“…Monochromatic red, far-red, or blue light was generated through LED SNAP-LITE (Quantum Devices). The quantification of hypocotyl elongation, and chlorophyll and anthocyanin content were performed as previously described (Kang et al, 2005).…”

Section: Possible Models Of Shb1 Functionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…HFR1 also plays a role in the regulation of several blue light-mediated responses (Duek and Fankhauser, 2003; X. Zhang et al, 2008). In addition, PHY-TOCHROME INTERACTING FACTOR4 (PIF4), HYPERSENSI-TIVE TO RED AND BLUE1, and OBF BINDING PROTEIN3 are all involved in red and blue light-mediated deetiolation responses (Huq and Quail, 2002;Kang et al, 2005;Ward et al, 2005).We previously showed that SHORT HYPOCOTYL UNDER BLUE1 (SHB1) has a negative effect on cryptochrome-mediated blue light responses in Arabidopsis (Kang and Ni, 2006). shb1, a T-DNA insertion loss-of-function allele, showed a short hypocotyl phenotype only under blue light, whereas shb1-D (shb1, Dominant), a gain-of-function overexpression allele, showed a long hypocotyl phenotype under blue as well as red or far-red light (Kang and Ni, 2006).…”

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SHORT HYPOCOTYL UNDER BLUE1 Truncations and Mutations Alter Its Association with a Signaling Protein Complex inArabidopsis

Zhou

2010

The Plant Cell

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Higher plants monitor their ambient light signals through red/far-red absorbing phytochromes and blue/UV-A light absorbing cryptochromes. Subsequent signaling cascades alter gene expression and initiate morphogenic responses. We previously isolated SHORT HYPOCOTYL UNDER BLUE1 (SHB1), a putative transcriptional coactivator in light signaling. SHB1 is homologous to the SYG1 protein family and contains an N-terminal SPX domain and a C-terminal EXS domain. Overaccumulation of the SPX domain caused a long hypocotyl phenotype similar to that of shb1-D under red, far-red, or blue light. By contrast, overaccumulation of the C-terminal EXS domain led to a short hypocotyl phenotype similar to that of shb1 under blue light. The N-terminal SPX domain was associated with a smaller protein complex than the native protein complex associated with endogenous SHB1. By contrast, the EXS domain was associated with a slightly smaller protein complex than the native protein complex, but it largely displaced endogenous SHB1 from its native protein complex. In addition, all six missense mutations that we identified from a suppressor screen were clustered within or close to the SPX domain, and these mutations impaired the assembly of the SHB1-containing protein complex. We propose that both SPX and EXS domains likely anchor SHB1 to a protein complex, and the SPX domain is critical for SHB1 signaling. INTRODUCTIONLight signals trigger deetiolation or photomorphogenic responses, including the inhibition of hypocotyl elongation, the opening of cotyledons and hypocotyl hooks, the expansion of cotyledons, and the development of chloroplasts, in most land plants. The effective wavelengths that regulate photomorphogensis are red and far-red light, which are perceived by phytochromes, and UV-A/blue light, which is perceived by cryptochromes. Among the five phytochrome members in Arabidopsis thaliana, phytochrome A (phyA) mainly regulates far-red light-mediated deetiolation responses, and phyB together with phyC, phyD, and phyE regulate red light-mediated deetiolation responses (Neff et al., 2000;Huq and Quail, 2005). Cryptochrome1 (cry1) and cry2 specifically regulate photomorphogensis under blue light (Ahmad and Cashmore, 1993;Lin et al., 1998). Blue light triggers the phosphorylation of cry1 and cry2 and activates a series of signaling events or activities downstream of blue light perception (Shalitin et al., 2002(Shalitin et al., , 2003. Recently, a basic helix-loop-helix transcription factor has been shown to interact with photoactivated cry2, suggesting the function of this transcription factor in early photoreceptor signaling in response to blue light .Other components downstream of crys include SHORT UN-DER BLUE1 (SUB1) and phosphatase 7 (PP7). SUB1 is a cytosolic calcium binding protein and acts in both blue and far-red light pathways, since sub1 showed a short hypocotyl phenotype under both blue and far-red light (Guo et al., 2001). PP7 is a Ser/ Thr phosphatase, and downregulation of PP7 caused a long hypocotyl phenotype under blue li...

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Section: Possible Models Of Shb1 Functionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

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SHORT HYPOCOTYL UNDER BLUE1 Truncations and Mutations Alter Its Association with a Signaling Protein Complex inArabidopsis

Zhou

2010

The Plant Cell

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“…The cry mutations impair blue light-mediated inhibition of hypocotyl elongation, the cop1 mutation causes short hypocotyls under both dark and light conditions, and hrb1 exhibits short hypocotyls under both red and blue light (Deng et al, 1992;Kang et al, 2005;Liu et al, 2011). However, CYCH;1 knockdown did not affect blue light-mediated inhibition of hypocotyl elongation (Fig.…”

Section: Discussionmentioning

confidence: 95%

CYCLIN H;1 Regulates Drought Stress Responses and Blue Light-Induced Stomatal Opening by Inhibiting Reactive Oxygen Species Accumulation in Arabidopsis

Zhou

Jin

Yoo³

et al. 2013

Plant Physiology

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Arabidopsis (Arabidopsis thaliana) CYCLIN-DEPENDENT KINASE Ds (CDKDs) phosphorylate the C-terminal domain of the largest subunit of RNA polymerase II. Arabidopsis CYCLIN H;1 (CYCH;1) interacts with and activates CDKDs; however, the physiological function of CYCH;1 has not been determined. Here, we report that CYCH;1, which is localized to the nucleus, positively regulates blue light-induced stomatal opening. Reduced-function cych;1 RNA interference (cych;1 RNAi ) plants exhibited a drought tolerance phenotype. CYCH;1 is predominantly expressed in guard cells, and its expression was substantially down-regulated by dehydration. Transpiration of intact leaves was reduced in cych;1 RNAi plants compared with the wild-type control in light but not in darkness. CYCH;1 down-regulation impaired blue light-induced stomatal opening but did not affect guard cell development or abscisic acid-mediated stomatal closure. Microarray and real-time polymerase chain reaction analyses indicated that CYCH;1 did not regulate the expression of abscisic acid-responsive genes or light-induced stomatal opening signaling determinants, such as MYB60, MYB61, Hypersensitive to red and blue1, and Protein phosphatase7. CYCH;1 down-regulation induced the expression of redox homeostasis genes, such as LIPOXYGENASE3 (LOX3), LOX4, ARABIDOPSIS GLUTATHIONE PEROXIDASE 7 (ATGPX7), EARLY LIGHT-INDUCIBLE PROTEIN1 (ELIP1), and ELIP2, and increased hydrogen peroxide production in guard cells. Furthermore, loss-of-function mutations in CDKD;2 or CDKD;3 did not affect responsiveness to drought stress, suggesting that CYCH;1 regulates the drought stress response in a CDKD-independent manner. We propose that CYCH;1 regulates blue light-mediated stomatal opening by controlling reactive oxygen species homeostasis.

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“…1 lists all components isolated so far through forward genetics that are likely involved in integration of more than one light signaling pathways. We have identified a short hypocotyl mutant under red and blue light, hrb1 for hypersensitive to red and blue 1 [51]. Mutation in HRB1 also enhances the end-of-day far-red light response, inhibits leaf expansion and petiole elongation, and attenuates the expression of CAB3 and CHS genes.…”

Section: Integration Of Red Far-red and Blue Light Signalingmentioning

confidence: 99%

Integration of light signaling with photoperiodic flowering and circadian rhythm

2005

Cell Res

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Plants become photosynthetic through de-etiolation, a developmental process regulated by red/far-red light-absorbing phytochromes and blue/ultraviolet A light-absorbing cryptochromes. Genetic screens have identified in the last decade many far-red light signaling mutants and several red and blue light signaling mutants, suggesting the existence of distinct red, far-red, or blue light signaling pathways downstream of phytochromes and cryptochromes. However, genetic screens have also identified mutants with defective de-etiolation responses under multiple wavelengths. Thus, the optimal de-etiolation responses of a plant depend on coordination among the different light signaling pathways. This review intends to discuss several recently identified signaling components that have a potential role to integrate red, far-red, and blue light signalings. This review also highlights the recent discoveries on proteolytic degradation in the desensitization of light signal transmission, and the tight connection of light signaling with photoperiodic flowering and circadian rhythm. Studies on the controlling mechanisms of de-etiolation, photoperiodic flowering, and circadian rhythm have been the fascinating topics in Arabidopsis research. The knowledge obtained from Arabidopsis can be readily applied to food crops and ornamental species, and can be contributed to our general understanding of signal perception and transduction in all organisms.

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HYPERSENSITIVE TO RED AND BLUE 1, a ZZ-Type Zinc Finger Protein, Regulates Phytochrome B–Mediated Red and Cryptochrome-Mediated Blue Light Responses

Cited by 52 publications

References 53 publications

SHORT HYPOCOTYL UNDER BLUE1 Truncations and Mutations Alter Its Association with a Signaling Protein Complex inArabidopsis

SHORT HYPOCOTYL UNDER BLUE1 Truncations and Mutations Alter Its Association with a Signaling Protein Complex inArabidopsis

CYCLIN H;1 Regulates Drought Stress Responses and Blue Light-Induced Stomatal Opening by Inhibiting Reactive Oxygen Species Accumulation in Arabidopsis

Integration of light signaling with photoperiodic flowering and circadian rhythm

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