ELONGATED HYPOCOTYL (HY5) AND HY5 HOMOLOG (HYH) maintain shade avoidance suppression in sunlight
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ABSTRACT:
ORGANISM(S): Arabidopsis thaliana
PROVIDER: GSE192469 | GEO | 2023/06/07
REPOSITORIES: GEO
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Project description:ELONGATED HYPOCOTYL (HY5) AND HY5 HOMOLOG (HYH) maintain shade avoidance suppression in sunlight
| PRJNA791625 | ENA
Project description:Reductions in red to far-red ratio (R:FR) provide plants with an unambiguous signal of vegetational shade and are monitored by phytochrome photoreceptors. Plants integrate this information with other environmental cues to determine the proximity and density of encroaching vegetation. Shade-sensitive species respond to reductions in R:FR by initiating a suite of developmental adaptations termed shade avoidance. These include the elongation of stems to facilitate light foraging. Hypocotyl elongation is driven by increased auxin biosynthesis promoted by PHYTOCHROME INTERACTING FACTORs (PIF) 4, 5 and 7. UV-B perceived by the UV RESISTANCE LOCUS 8 (UVR8) photoreceptor rapidly inhibits shade avoidance, in part by suppressing PIF4/5 transcript accumulation and destabilising PIF4/5 protein. Here, we show that longer-term inhibition of shade avoidance is sustained by ELONGATED HYPOCOTYL 5 (HY5) and HY5 HOMOLOGUE (HYH), which regulate transcriptional reprogramming of genes involved in hormone signalling and cell wall modification. HY5 and HYH are elevated in UV-B and suppress the expression of XYLOGLUCAN ENDOTRANSGLUCOSYLASE/HYDROLASE (XTH) genes involved in cell wall loosening. They additionally increase expression GA2-OXIDASE1 (GA2ox1) and GA2ox2, encoding gibberellin catabolism enzymes that act redundantly to stabilise the PIF-inhibiting DELLA proteins. UVR8 therefore regulates temporally distinct signalling pathways to first rapidly inhibit and subsequently maintain suppression of shade avoidance following UV-B exposure.
| S-EPMC10953383 | biostudies-literature
Project description:Three bZIP transcription factors (TFs), namely GBF1, HY5, and HYH, form heterodimers with each other and regulate photomorphogenesis in an interdependent manner. GBF1 acts as both a positive and negative regulator of photomorphogenesis, whereas HY5 and HYH mainly act as positive regulators of photomorphogenesis. To study the effect of HY5 and HYH on GBF1-mediated genome-wide expression, transcript profiling was performed in the gbf1 single mutant and gbf1hy5 and gbf1hyh double mutants. Our study revealed that GBF1 mainly acts antagonistic to HY5 and HYH for genome-wide expression.
2016-04-01 | GSE36964 | GEO
Project description:Transcription factors are key components of light signalling as they amplify the signal, which results in massive changes in genome-wide expression during photomorphogenesis. Three bZIP transcription factors (TFs), namely GBF1, HY5, and HYH, form heterodimers with each other and regulate photomorphogenesis in an interdependent manner. GBF1 acts as both a positive and negative regulator of photomorphogenesis, whereas HY5 and HYH mainly act as positive regulators of photomorphogenesis. In this study, the impact of heterodimerization of GBF1 with HY5 and HYH was analyzed for genome-wide binding of GBF1 through ChIP-chip in GBF1. We identified more than 2000 direct targets of GBF1 in the presence of HY5 and HYH. However, in the absence of HY5, very few binding sites were found, and in the absence of functional HYH protein, the number of GBF1 direct targets reduced to only half compared to when functional HYH was present.
2014-03-24 | GSE36965 | GEO
Project description:Plants maintain iron (Fe) homeostasis under varying environmental conditions by balancing processes such as Fe uptake, transport, and storage. In Arabidopsis, POPEYE (PYE), a basic helix-loop-helix (bHLH) transcription factor (TF), has been shown to play a crucial role in regulating this balance. In recent years, the mechanisms regulating Fe uptake have been well established but the upstream transcriptional regulators of Fe transport and storage are still poorly understood. In this study, we report that ELONGATED HYPOCOTYL5 (HY5), a basic leucine zipper (bZIP) TF which has recently been shown to play a crucial role in Fe homeostasis, interacts with PYE. Molecular, genetic and biochemical approaches revealed that PYE and HY5 have overlapping as well as some distinct roles in regulation of Fe deficiency response. We found that HY5 and PYE both act as a repressor of Fe transport genes such as YSL3, FRD3, NPF5.9, YSL2, NAS4, and OPT3. HY5 was found to directly bind on the promoter of these genes and regulate intercellular Fe transport. Further analysis revealed that HY5 and PYE directly interact at the same region on PYE and NAS4 promoter. Overall, this study revealed that HY5 regulates Fe homeostasis by physically interacting with PYE as well as independently.
2024-09-02 | E-MTAB-14365 | biostudies-arrayexpress
Project description:Three bZIP transcription factors (TFs), namely GBF1, HY5, and HYH, form heterodimers with each other and regulate photomorphogenesis in an interdependent manner. GBF1 acts as both a positive and negative regulator of photomorphogenesis, whereas HY5 and HYH mainly act as positive regulators of photomorphogenesis. To study the effect of HY5 and HYH on GBF1-mediated genome-wide expression, transcript profiling was performed in the gbf1 single mutant and gbf1hy5 and gbf1hyh double mutants. Our study revealed that GBF1 mainly acts antagonistic to HY5 and HYH for genome-wide expression. Four-day-old constant white-light grown Arabidipsis seedlings of wild-type (Col-0), gbf1 mutant, gbf1 hy5 double mutant and gbf1 hyh double mutant were harvested for total RNA extraction and Affymetrix microarray hybridisation. Two biological replicates of each sample were used for hybridisation and data analysis. Data were analysed using GeneSpring software by utilising the RMA algorithm. To draw the conclusions from this study, probe level intensity of gbf1, gbf1 hy5, and gbf1 hyh was normalised against the probe level intensity of wild-type, and also the probe level intensity of gbf1 hy5 and gbf1 hyh double mutants was normalised against the probe level intensity of the gbf1 single mutant.
2016-04-01 | E-GEOD-36964 | biostudies-arrayexpress
Project description:Transcription factors are key components of light signalling as they amplify the signal, which results in massive changes in genome-wide expression during photomorphogenesis. Three bZIP transcription factors (TFs), namely GBF1, HY5, and HYH, form heterodimers with each other and regulate photomorphogenesis in an interdependent manner. GBF1 acts as both a positive and negative regulator of photomorphogenesis, whereas HY5 and HYH mainly act as positive regulators of photomorphogenesis. In this study, the impact of heterodimerization of GBF1 with HY5 and HYH was analyzed for genome-wide binding of GBF1 through ChIP-chip in GBF1. We identified more than 2000 direct targets of GBF1 in the presence of HY5 and HYH. However, in the absence of HY5, very few binding sites were found, and in the absence of functional HYH protein, the number of GBF1 direct targets reduced to only half compared to when functional HYH was present. ChIPed DNA with GBF1 antibody from GBF1OE, hy5 GBF1OE, and hyh GBF1OE lines vs. ChIPed DNA with GBF1 antibody from wild-type.
2014-03-24 | E-GEOD-36965 | biostudies-arrayexpress
Project description:Arabidopsis is a shade avioding plant. Under simulated shade light with reduced red-to-far red (R:FR) ratio around 0.7, hypocotyls of Arabidopsis seedlings elongate, which is one of the typical shade avoidance responses.We discovered that when the R:FR ratio further decreases to around 0.1 (strong shade), the shade-induced elongation of hypocotyl is abolished and phytochrome A (phyA) mediates this response.In this study, we aim to examine the difference between shade and strong shade treatment and uncover the role of phyA in regulating the shade avoidance responses.
2019-12-21 | GSE55899 | GEO
Project description:Arabidopsis thaliana seedlings comprising hy5 single mutant , hyh single mutant, hy5 hyh double mutant and wild-type plants were germinated in the dark on agar medium on usual Murashig and Skoog medium (pH 5.8) without sucrose. After 3 days of germination, etiolated seedlings were transfered to light conditions in liquid media similar to previous one but without agar . After 5 hours, auxin (10 micromolar IAA) was added to all treated samples except to controls (Mock treatment). all samples were harvested after one-hour treatment and frozen for further RNA extraction. Aim of the project was to detect impact of exogenous auxin treatment on each genotype
2006-11-08 | E-MEXP-715 | biostudies-arrayexpress
Project description:Circadian clocks are gene networks producing 24-h oscillations at the level of clock gene expression that is synchronized to environmental cycles via light signals. The ELONGATED HYPOCOTYL 5 (HY5) transcription factor is a signalling hub acting downstream of several photoreceptors and is a key regulator of photomorphogenesis. Here we describe a mechanism by which light quality could modulate the pace of the circadian clock through controlling abundance of HY5. We show that hy5 mutants display remarkably shorter period rhythms in blue but not in red light or darkness and blue light is more efficient than red to induce accumulation of HY5 at transcriptional and post-transcriptional levels. We demonstrate that the pattern and level of HY5 accumulation modulates its binding to specific promoter elements of majority of clock genes, but only a few of these show altered transcription in the hy5 mutant. Mathematical modelling suggests that the direct effect of HY5 on the apparently non-responsive clock genes could be masked by feed-back from the clock gene network. We conclude that the information on the ratio of blue and red components of the white light spectrum is decoded and relayed to the circadian oscillator, at least partially, by HY5.
2018-09-05 | GSE117797 | GEO