Arabidopsis thaliana
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ABSTRACT:
PROVIDER: PRJNA204973 | ENA |
REPOSITORIES: ENA
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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: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: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:GIGANTEA (GI) is a plant-specific, circadian clock-regulated, nuclear protein with pleiotropic functions studied in many plant species. It is involved in flowering, circadian clock control, chloroplast biogenesis, carbohydrate metabolism, stress responses and synthesis of volatiles. In potato (Solanum tuberosum L.), however, only its role in tuber initiation is reported. Based on the findings in other plant species we hypothesized that the function of GI is not restricted to tuberization in potato. To test this hypothesis we repressed the expression of a GI gene, StGI.04 in the commercial potato cultivar ‘Désirée’ and investigated the effect of repression at morphological and transcriptome level. We found that, like GI in other plant species, StGI.04 influences the expression of the key genes of circadian clock, flowering, starch synthesis and stress responses. Furthermore, we detected a novel function of a GI gene in influencing the anthocyanin synthesis and skin colour of potato tubers.
2022-03-30 | GSE189956 | GEO
Project description:Plant microRNAs undergo stepwise-nuclear maturation before engaging cytosolic sequence-complementary transcripts in association with the silencing-effector protein ARGONAUTE1(AGO1). How plant miRNAs translocate to the cytosol remains mysterious as does their cellular loading site(s) into AGO1. Here, we show that the N-termini of plant AGO1s contain a nuclear-localization (NLS) and nuclear-export signal (NES), which, in Arabidopsis thaliana (At) enables AtAGO1 nucleo-cytosolic shuttling in a Leptomycin-B-inhibited manner, diagnostic of CRM1(Expo1)/NES-dependent nuclear export. Nuclear-only AtAGO1 contains the same 2’O-methylated miRNA cohort as its nucleo-cytosolic counterpart, but specifically interacts with the miRNA loading-chaperone HSP90. AtAGO1 nucleo-cytosolic shuttling is required for mature miRNA translocation and for miRNA-mediated silencing. We propose that plant miRNAs are matured, methylated, loaded into AGO1 in the nucleus, and exported cytoplasmically as AGO1:miRNA complexes in a CRM1(Expo1)/NES-dependent manner.
2018-01-04 | GSE100395 | GEO
Project description:Plants are sessile organisms that have acquired highly plastic developmental strategies to adapt to the environment. Among these processes, the floral transition is essential to ensure reproductive success and is finely regulated by several internal and external genetic networks. The photoperiodic pathway, which controls the plant response to day length, is one of the most important pathways controlling flowering. In Arabidopsis photoperiodic flowering, CONSTANS (CO) is the central gene activating the expression of the florigen FLOWERING LOCUS T (FT) in the leaves at the end of a long day. CO expression is strongly regulated by the circadian clock. However, to date, no evidence has been reported regarding a feedback loop from the photoperiod pathway back to the circadian clock. Using transcriptional networks, we have identified relevant network motifs regulating the interplay between the circadian clock and the photoperiod pathway. Gene expression, chromatin immunoprecipitation experiments and phenotypic analysis allowed us to elucidate the role of CO over the circadian clock. Plants with altered CO expression showed a different internal clock period, measured by daily rhythmic movements in the leaves. We show that CO is able to activate key genes related to the circadian clock, such as CCA1, LHY, PRR5 and GI, at the end of a long day by binding to specific sites on their promoters. Moreover, a significant number of PRR5 repressed target genes are upregulated by CO, and this could explain the phase transition promoted by CO. The CO-PRR5 complex interacts with the bZIP transcription factor HY5 and helps to localize the complex in the promoters of clock genes. Our results indicate that there may be a feedback loop in which CO communicates back to the circadian clock, feeding seasonal information to the circadian system.
2023-08-01 | GSE236178 | GEO
Project description:Plants are sessile organisms that have acquired highly plastic developmental strategies to adapt to the environment. Among these processes, the floral transition is essential to ensure reproductive success and is finely regulated by several internal and external genetic networks. The photoperiodic pathway, which controls the plant response to day length, is one of the most important pathways controlling flowering. In Arabidopsis photoperiodic flowering, CONSTANS (CO) is the central gene activating the expression of the florigen FLOWERING LOCUS T (FT) in the leaves at the end of a long day. CO expression is strongly regulated by the circadian clock. However, to date, no evidence has been reported regarding a feedback loop from the photoperiod pathway back to the circadian clock. Using transcriptional networks, we have identified relevant network motifs regulating the interplay between the circadian clock and the photoperiod pathway. Gene expression, chromatin immunoprecipitation experiments and phenotypic analysis allowed us to elucidate the role of CO over the circadian clock. Plants with altered CO expression showed a different internal clock period, measured by daily rhythmic movements in the leaves. We show that CO is able to activate key genes related to the circadian clock, such as CCA1, LHY, PRR5 and GI, at the end of a long day by binding to specific sites on their promoters. Moreover, a significant number of PRR5 repressed target genes are upregulated by CO, and this could explain the phase transition promoted by CO. The CO-PRR5 complex interacts with the bZIP transcription factor HY5 and helps to localize the complex in the promoters of clock genes. Our results indicate that there may be a feedback loop in which CO communicates back to the circadian clock, feeding seasonal information to the circadian system.
2024-01-01 | GSE222657 | GEO
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: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
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.
2024-09-02 | BIOMD0000000089 | BioModels