Identifying Y candidate genes
Ontology highlight
ABSTRACT:
ORGANISM(S): Arabidopsis thaliana
SUBMITTER: Kieron Edwards
PROVIDER: E-GEOD-19263 | biostudies-arrayexpress |
REPOSITORIES: biostudies-arrayexpress
Similar Datasets
Project description:The circadian clock generates biological rhythms with a period of approximately 24 hours. Using microarray experiments, we have previously shown that approximately 16% of the Arabidopsis genome is regulated in a circadian manner (Edwards et al., 2006). Previous work from our lab in modelling the molecular oscillator of Arabidopsis introduced a hypothetical component Y into an evening loop of the clock gene network (Locke et al., 2005). GIGANTEA (GI) was suggested as a strong candidate for Y based on genetic evidence and its close matching of the expression profile predicted by the mathematical modelling. Recent experimental evidence suggests that GI may only partially account for the function of Y. Thus, we are undertaking a genomics approach to identify other candidate genes that match the predicted expression profile of Y. Samples were taken from wild type and lhy cca1 double mutant seedlings from 4 timepoints around the night to day transition (-15mins, +15mins, +30mins and +60mins) after 9 days of growth in 18:6 light dark cycles. We aim to identify genes showing the light induction response predicted for Y around dawn.
2009-12-10 | GSE19263 | GEO
Project description:GIGANTEA (GI) is an important modulator of plant circadian system. Recent studies have reported that protein GI is localized in both nucleus and cytosol, and nuclear and cytosolic GI exert differential effect on plant circadian clock. We first generated GI-null mutants and transgenic Arabidopsis plants that expressed GI fused to green fluorescent protein gene (GIpro::GI-GFP) and GI-GFP with a nuclear localization signal (GIpro::GI-GFP-NLS) or with a nuclear export signal (GIpro::GI-GFP-NES) under the control of native promoter in GI-null mutants. To investigate differential roles of nuclear and cytosolic GI in regulating plant circadian clock, we performed genome-wide gene expression profiling for wild-type plants and the GI-transgenic plants at morning and evening, and analyzed complementation patterns of gi-2 lesion by nuclear and cytosolic GI. As a result, we identified four complementation patterns representing genes affected by only nuclear GI (GIN) or cytosolic GI (GIC), those by either GIN or GIC, and those by the action of both GIN and GIC. Furthermore, we compared the transgenic plants expressing GIpro::GI-GFP with WT and the other GI-transgenic plants to confirm whether abnormally expressed genes by the gi-2 mutation can be complemented by restoring protein GI. Wild-type plants (Col), GI-null mutants (gi-2), and the other transgenic gi-2 plants expressing GIpro::GI-GFP (called GI plants), GIpro::GI-GFP-NLS (called GI-NLS plants), and GIpro::GI-GFP-NES (called GI-NES plants) were grown for seven days under conditions of 16 h light and 8 h dark (LD) and harvested at 1h (ZT1) and 16 hr (ZT16) after the light is turned on, representing morning and evening, respectively. mRNA levels were measured from three biological replicates of Col, gi-2, GI-NLS, GI-NES, and GI.
2013-09-01 | E-GEOD-47169 | biostudies-arrayexpress
Project description:GIGANTEA (GI) is an important modulator of plant circadian system. Recent studies have reported that protein GI is localized in both nucleus and cytosol, and nuclear and cytosolic GI exert differential effect on plant circadian clock. We first generated GI-null mutants and transgenic Arabidopsis plants that expressed GI fused to green fluorescent protein gene (GIpro::GI-GFP) and GI-GFP with a nuclear localization signal (GIpro::GI-GFP-NLS) or with a nuclear export signal (GIpro::GI-GFP-NES) under the control of native promoter in GI-null mutants. To investigate differential roles of nuclear and cytosolic GI in regulating plant circadian clock, we performed genome-wide gene expression profiling for wild-type plants and the GI-transgenic plants at morning and evening, and analyzed complementation patterns of gi-2 lesion by nuclear and cytosolic GI. As a result, we identified four complementation patterns representing genes affected by only nuclear GI (GIN) or cytosolic GI (GIC), those by either GIN or GIC, and those by the action of both GIN and GIC. Furthermore, we compared the transgenic plants expressing GIpro::GI-GFP with WT and the other GI-transgenic plants to confirm whether abnormally expressed genes by the gi-2 mutation can be complemented by restoring protein GI.
2013-09-01 | GSE47169 | GEO
Project description:The Evening Complex (EC) is a core component of the circadian clock, which represses target gene expression at the end of the day and integrates temperature information in order to coordinate environmental and endogenous signals. Despite its importance, the mechanism of EC function remains unknown. Here we show that the EC recruits repressive chromatin domains to regulate the evening transcriptome. The EC component EARLY FLOWERING 3 (ELF3) directly interacts with a protein from the Swi2/Snf2-Related 1 (SWR1) complex to control deposition of H2A.Z-nucleosomes at the EC target genes. The SWR1 components display a circadian oscillation in gene expression with a peak at dusk, suggesting that the circadian clock controls the expression and function of SWR1. In turn, SWR1 is required for the circadian clockwork as defects in SWR1 activity alters morning-expressed genes. The EC-SWR1 complex binds to the promoters of the core clock genes PSEUDORESPONSE REGULATOR 7 (PRR7) and PRR9 and catalyzes H2A.Z deposition coincident with their repression at dusk. This provides a mechanism by which the circadian clock temporally establishes repressive chromatin domains to shape oscillatory gene expression around dusk.
2020-01-22 | GSE109101 | GEO
Project description:This a model from the article:
Experimental validation of a predicted feedback loop in the multi-oscillator clock of Arabidopsis thaliana.
Locke JC, Kozma-Bognár L, Gould PD, Fehér B, Kevei E, Nagy F, Turner MS, Hall A, Millar AJ
Mol. Syst. Biol.2006;Volume:2;Page:59
17102804,
Abstract:
Our computational model of the circadian clock comprised the feedback loop between LATE ELONGATED HYPOCOTYL (LHY), CIRCADIAN CLOCK ASSOCIATED 1 (CCA1) and TIMING OF CAB EXPRESSION 1 (TOC1), and a predicted, interlocking feedback loop involving TOC1 and a hypothetical component Y. Experiments based on model predictions suggested GIGANTEA (GI) as a candidate for Y. We now extend the model to include a recently demonstrated feedback loop between the TOC1 homologues PSEUDO-RESPONSE REGULATOR 7 (PRR7), PRR9 and LHY and CCA1. This three-loop network explains the rhythmic phenotype of toc1 mutant alleles. Model predictions fit closely to new data on the gi;lhy;cca1 mutant, which confirm that GI is a major contributor to Y function. Analysis of the three-loop network suggests that the plant clock consists of morning and evening oscillators, coupled intracellularly, which may be analogous to coupled, morning and evening clock cells in Drosophila and the mouse.
The model describes a three loops model of the Arabidopsis circadian clock. It provides initial conditions, parameter values and reactions for the production rates of the following species: LHY mRNA (cLm), cytoplasmic LHY (cLc), nuclear LHY (cLn), TOC1 mRNA (cTm), cytoplasmic TOC1 (cTc), nuclear TOC1 (cTn), X mRNA (cXm), cytoplasmic X (cXc), nuclear X (cXn), Y mRNA (cYm), cytoplasmic Y (cYc), nuclear Y (cYn), nuclear P (cPn), APRR7/9 mRNA, cytoplasmic APRR7/9, and nuclear APRR7/9.
The paper describes the behaviour of the model in constant light (LL) and day-night cycle (LD). However, the current model only contains the LL cycle. Some parameter values should be changed from the wild-type (WT) ones in order to simulate the effect of mutations. These changes are listed in the notes of relevant parameters.
This model originates from BioModels Database: A Database of Annotated Published Models. It is copyright (c) 2005-2009 The BioModels Team.For more information see the terms of use.To cite BioModels Database, please use Le Novère N., Bornstein B., Broicher A., Courtot M., Donizelli M., Dharuri H., Li L., Sauro H., Schilstra M., Shapiro B., Snoep J.L., Hucka M. (2006) BioModels Database: A Free, Centralized Database of Curated, Published, Quantitative Kinetic Models of Biochemical and Cellular Systems Nucleic Acids Res., 34: D689-D691.
2007-02-20 | BIOMD0000000089 | BioModels
Project description:Plants use their endogenous clock to regulate many physiological processes related to their survival and adaptability. GIGANTEA (GI), one of the clock proteins, contributes to the maintenance of circadian period length and amplitude and also regulates flowering time and hypocotyl growth in response to day length. In addition to GI, EARLY FLOWERING 4 (ELF4), another clock regulator, also contributes to these processes. However, little is known about the overall interactions between GI and ELF4 in Arabidopsis. In this study, we investigated the genetic interactions between GI and ELF4 in circadian output regulation. The results show that GI is dominant to ELF4 in flowering time determination, but ELF4 is dominant to GI in hypocotyl growth regulation. Moreover, GI and ELF4 have a synergistic effect on endogenous clock regulation. Further, gene expression profiling of gi-2, elf4, and gi-2 elf4 mutants confirmed that GI and ELF4 had differential dominant effects on circadian physiological outputs at dawn and dusk, respectively. This differential dominance of GI and ELF4 provides a potential means to achieve the diversity in the regulation of circadian physiological outputs including flowering time and hypocotyl growth. The genetic interactions between GI and ELF4 could be time-dependent functional dominance along a day, called temporal dominance hereafter. To test this hypothesis, we performed gene expression profiling of WT, gi-2, elf4 and gi elf4 plants at dawn (ZT1) and dusk (ZT16).
2012-06-30 | E-GEOD-32938 | biostudies-arrayexpress
Project description:In many organisms, the circadian clock is composed of functionally coupled morning and evening oscillators that regulate the bouts of dawn and dusk activity. In Arabidopsis, oscillator coupling relies on a core loop in which the evening oscillator component TOC1 was proposed to activate a subset of morning-expressed oscillator genes. Our systems-biological approach overturns the current view of the Arabidopsis circadian clock showing that TOC1 does not function as an activator but as a timely-controlled general repressor of morning and evening oscillator components. Repression occurs through rhythmic binding to the promoters of all oscillator genes, suggesting a previously unexpected direct connection between the morning and evening loops.
2012-03-08 | GSE35952 | GEO
Project description:In many organisms, the circadian clock is composed of functionally coupled morning and evening oscillators that regulate the bouts of dawn and dusk activity. In Arabidopsis, oscillator coupling relies on a core loop in which the evening oscillator component TOC1 was proposed to activate a subset of morning-expressed oscillator genes. Our systems-biological approach overturns the current view of the Arabidopsis circadian clock showing that TOC1 does not function as an activator but as a timely-controlled general repressor of morning and evening oscillator components. Repression occurs through rhythmic binding to the promoters of all oscillator genes, suggesting a previously unexpected direct connection between the morning and evening loops. Examination of TOC1 genome-wide binding using TOC1 Minigene (TMG) seedlings expressing the genomic fragment of TOC1 fused to the Yellow Fluorescent Protein in a toc1-2 mutant background (TMG-YFP/toc1-2 seedlings) grown under LD cycles (12h light:12h dark).
2012-03-08 | E-GEOD-35952 | biostudies-arrayexpress
Project description:The circadian clock is comprised of proteins that form negative feedback loops, which regulate the timing of global gene expression in a coordinated 24 hour cycle. As a result, the plant circadian clock is responsible for regulating numerous physiological processes central to growth and survival. To date, most plant circadian clock studies have relied on diurnal transcriptome changes to elucidate molecular connections between the circadian clock and observable phenotypes in wild-type plants. Here, we have combined high-throughput RNA-sequencing and mass spectrometry to comparatively characterize the lhycca1, prr7prr9, gi and toc1 circadian clock mutant rosette transcriptome and proteome at the end-of-day and end-of-night.
2018-01-02 | PXD004763 | Pride
Project description:Plants use their endogenous clock to regulate many physiological processes related to their survival and adaptability. GIGANTEA (GI), one of the clock proteins, contributes to the maintenance of circadian period length and amplitude and also regulates flowering time and hypocotyl growth in response to day length. In addition to GI, EARLY FLOWERING 4 (ELF4), another clock regulator, also contributes to these processes. However, little is known about the overall interactions between GI and ELF4 in Arabidopsis. In this study, we investigated the genetic interactions between GI and ELF4 in circadian output regulation. The results show that GI is dominant to ELF4 in flowering time determination, but ELF4 is dominant to GI in hypocotyl growth regulation. Moreover, GI and ELF4 have a synergistic effect on endogenous clock regulation. Further, gene expression profiling of gi-2, elf4, and gi-2 elf4 mutants confirmed that GI and ELF4 had differential dominant effects on circadian physiological outputs at dawn and dusk, respectively. This differential dominance of GI and ELF4 provides a potential means to achieve the diversity in the regulation of circadian physiological outputs including flowering time and hypocotyl growth.
2012-07-01 | GSE32938 | GEO