Rhythmic growth explained by coincidence between internal and external cues
Ontology highlight
ABSTRACT:
ORGANISM(S): Arabidopsis thaliana
PROVIDER: GSE6906 | GEO | 2007/06/24
SECONDARY ACCESSION(S): PRJNA98157
REPOSITORIES: GEO
Similar Datasets
Project description:Plant hypocotyls elongate in response to darkness. The response to darkness is gated by the circadian clock, such that wild-type plants (Col) only respond to darkness with growth once every 24 hours, whereas arrhythmic lines, such as CCA1-34, will respond to darkness with growth at any time of day. The experiment here was designed to find genes whose expression was correlated with growth. It should also pick up other genes that are gated by the circadian clock or that are direct targets of CCA1. Experiment Overall Design: Two genotypes were uses, wild-type (Col) and the arrhythmic CCA1-34 line that overexpresses the CCA1 protein. Plants were entrained in short day conditions for four days and then subjected light/dark pulses consisting of 160 minutes of light and 320 minutes of dark. We collected samples 120 minutes into the first and last dark periods of the day, corresponding to 280 and 1240 minutes after dawn. At the 280 minute time point Col plants are growing in response to darkness. At the 1240 minute time point Col plants are not growing. CCA1-34 plants are growing at both time points. The collection regime was continued for three days for a total of three temporal replicates for each time point/genotype combination.
2008-06-15 | E-GEOD-6906 | biostudies-arrayexpress
Project description:We have previously demonstrated that the arrhythmic expressions of circadian clock genes due to constant darkness induce glycometabolic and reproductive hallmarks of polycystic ovary syndrome (PCOS) in rats. Limosilactobacillus reuteri (L.reuteri) is a promising dietary intervention for host dysmetabolism, while its potential effect on circadian dysrhythmia-induced PCOS remains elusive. Here, we evaluated the amelioration of L.reuteri regimen on constant darkness-induced PCOS-like rats through detecting hepatic gene expression profiles by RNA-seq.
2023-07-11 | GSE169501 | GEO
Project description:The red-light regulated transcription factors FHY3 and FAR1 form a key point of light input to the plant circadian clock in positively regulating expression of genes within the central clock. However, the fhy3 mutant shows an additional red light-specific disruption of rhythmicity which is inconsistent with this role. Here we demonstrate that only fhy3 and not far1 mutants show this red specific disruption of rhythmicity. We examined the differences in rhythmic transcriptome in red versus white light and reveal differences in patterns of rhythmicity among the central clock proteins suggestive of a change in emphasis withing the central mechanism of the clock, changes which underlie the red specificity of the fhy3 mutant. In particular, changes in enrichment of promoter elements were consistent with a key role for the HY5 transcription factor, a known integrator of the ratio of red to blue light in regulation of the clock. Examination of differences in the rhythmic transcriptome in the fhy3 mutant in red light which identified specific disruption of the CCA1-regulated ELF3 and LUX central clock genes, while the CCA1 target TBS element, TGGGCC, was enriched among genes that became arrhythmic. Coupled with the known interaction of FHY3 but not FAR1 with CCA1 we propose that the red-specific circadian phenotype of fhy3 may involve disruption of the previously-demonstrated moderation of CCA1 activity by FHY3 rather than a disruption of its own transcriptional regulatory activity. Together, this evidence suggests a conditional redundancy between FHY3 and HY5 in the integration of red and blue light input to the clock in order to enable a plasticity in response to light and optimise plant adaptation. Furthermore, our evidence also suggests changes in CCA1 activity between red and white light transcriptomes. This, together with the documented interaction of HY5 with CCA1, leads us to propose a model whereby this integration of red and blue signals may at least partly occur via direct FHY3 and HY5 interaction with CCA1 leading to moderation of CCA1 activity.
2022-05-23 | GSE201929 | GEO
Project description:The plant circadian clock exerts a critical role in the regulation of multiple biological processes including responses to biotic and abiotic stresses. It is estimated that the clock regulates up to 80% of the transcriptome in Arabidopsis, thus understanding the molecular mechanisms that control this rhythmic transcriptome requires identification of the targets of each clock component. The Arabidopsis core clock is partially comprised of a transcriptional regulatory loop between the MYB domain containing transcription factors CIRCADIAN CLOCK ASSOCIATED1 (CCA1) and LATE ELONGATED HYPOCOTYL (LHY), and TIMING OF CAB EXPRESSION1 (TOC1). As a key component of the clock, CCA1 is able to initiate and set the phase of clock-controlled rhythms. CCA1 regulates the transcription of several genes by directly binding to the evening element (EE) motif primarily found in the promoters of evening expressed genes. Using a genome-wide approach we have identified direct targets of CCA1 in plants grown in constant (LL) and driven conditions (LD). These CCA1 targets are enriched for a myriad of biological processes and stress responses. While many of these target genes are evening phased and contain the EE in their promoter regions, a significant subset is morning phased and lack an EE. Furthermore, several CCA1 targets do not cycle in either LL or LD or both. Expression analysis in CCA1 overexpressing plants confirms CCA1 regulation of analyzed targets. Our results emphasize an expanded role for the circadian clock in regulation of key pathways in Arabidopsis, and provide a comprehensive and solid resource for future functional studies. ChIP-Seq of CCA1-GFP plants under control of the CCA1 promoter in continuous light and diel conditions
2015-07-26 | E-GEOD-70533 | biostudies-arrayexpress
Project description:The plant circadian clock exerts a critical role in the regulation of multiple biological processes including responses to biotic and abiotic stresses. It is estimated that the clock regulates up to 80% of the transcriptome in Arabidopsis, thus understanding the molecular mechanisms that control this rhythmic transcriptome requires identification of the targets of each clock component. The Arabidopsis core clock is partially comprised of a transcriptional regulatory loop between the MYB domain containing transcription factors CIRCADIAN CLOCK ASSOCIATED1 (CCA1) and LATE ELONGATED HYPOCOTYL (LHY), and TIMING OF CAB EXPRESSION1 (TOC1). As a key component of the clock, CCA1 is able to initiate and set the phase of clock-controlled rhythms. CCA1 regulates the transcription of several genes by directly binding to the evening element (EE) motif primarily found in the promoters of evening expressed genes. Using a genome-wide approach we have identified direct targets of CCA1 in plants grown in constant (LL) and driven conditions (LD). These CCA1 targets are enriched for a myriad of biological processes and stress responses. While many of these target genes are evening phased and contain the EE in their promoter regions, a significant subset is morning phased and lack an EE. Furthermore, several CCA1 targets do not cycle in either LL or LD or both. Expression analysis in CCA1 overexpressing plants confirms CCA1 regulation of analyzed targets. Our results emphasize an expanded role for the circadian clock in regulation of key pathways in Arabidopsis, and provide a comprehensive and solid resource for future functional studies.
2015-07-26 | GSE70533 | GEO
Project description:The timing of behavior under natural light-dark conditions is a function of circadian clocks and photic input pathways. Yet a mechanistic understanding of how these pathways collaborate in animals is lacking. Here we demonstrate in Drosophila that the Phosphatase of Regenerating Liver-1 (PRL-1) sets period length and behavioral phase gated by photic signals. PRL-1 knockdown in PDF clock neurons dramatically lengthens circadian period. PRL-1 mutants exhibit allele-specific interactions with the light- and clock-regulated gene timeless (tim). Moreover, we show that PRL-1 promotes TIM accumulation and dephosphorylation. Interestingly, the PRL-1 mutant period lengthening is suppressed in constant light and PRL-1 mutants display a delayed phase under short, but not long, photoperiod conditions. Thus, our studies reveal that PRL-1 dependent dephosphorylation of TIM is a core mechanism of the clock that sets period length and phase in darkness, enabling the behavioral adjustment to changing day-night cycles.
2020-11-11 | PXD020986 | Pride
Project description:LHY and CCA1 encode single MYB transcription factors, involved in circadian clock. However, direct target genes of LHY and CCA1 in a genomic scale were largely unknown. To reveal bound genes by CCA1, chimeric protein CCA1-FLAG was expressed under CCA1 promoter in cca1 lhy (CCA1pro:CCA1-FLAG/ cca1 lhy). ChIP was performed using anti-FLAG antibody (F3165; SIGMA), which was bound to Dynabeads Protein G (100-03D; Life Technologies), and ChIP DNA were analyzed by IonPGM or Illumina GAII.
2016-03-11 | GSE67903 | GEO
Project description:Background. The transcriptional circuits of circadian clocks control physiological and behavioral rhythms. Light may affect such overt rhythms in two ways: (1) by entraining the clock circuits and (2) via clock-independent molecular pathways. In this study we examine the relationship between autonomous transcript oscillations and light-driven transcript responses Methodology/Principal Findings. Transcript profiles of wild-type and arrhythmic mutant Drosophila were recorded both in the presence of an environmental photocycle and in constant darkness. Systematic autonomous oscillations in the 12-48 hr period range were detectable only in wild-type flies and occurred preferentially at the circadian period length. However, an extensive program of light-driven expression was confirmed in arrhythmic mutant flies. Many lightresponsive transcripts are preferentially expressed in the adult compound eye and the phospholipase C component of phototransduction, NO RECEPTOR POTENTIAL (NORPA), is required for their light-dependent regulation. Conclusions/Significance. Although there is growing evidence for the existence of multiple molecular clock circuits in plants and fungi, Drosophila appears to possess only one such system. The sustained photic expression responses identified here are partially coupled to the circadian clock and may reflect a mechanism for flies to modulate functions such as visual sensitivity and synaptic transmission in response to seasonal changes in photoperiod. Keywords: Time course
2006-02-03 | GSE3832 | GEO
Project description:Background. The transcriptional circuits of circadian clocks control physiological and behavioral rhythms. Light may affect such overt rhythms in two ways: (1) by entraining the clock circuits and (2) via clock-independent molecular pathways. In this study we examine the relationship between autonomous transcript oscillations and light-driven transcript responses Methodology/Principal Findings. Transcript profiles of wild-type and arrhythmic mutant Drosophila were recorded both in the presence of an environmental photocycle and in constant darkness. Systematic autonomous oscillations in the 12-48 hr period range were detectable only in wild-type flies and occurred preferentially at the circadian period length. However, an extensive program of light-driven expression was confirmed in arrhythmic mutant flies. Many lightresponsive transcripts are preferentially expressed in the adult compound eye and the phospholipase C component of phototransduction, NO RECEPTOR POTENTIAL (NORPA), is required for their light-dependent regulation. Conclusions/Significance. Although there is growing evidence for the existence of multiple molecular clock circuits in plants and fungi, Drosophila appears to possess only one such system. The sustained photic expression responses identified here are partially coupled to the circadian clock and may reflect a mechanism for flies to modulate functions such as visual sensitivity and synaptic transmission in response to seasonal changes in photoperiod. Keywords: Time course
2006-02-03 | GSE3831 | GEO
Project description:Mammals rely on a network of circadian clocks to control daily systemic metabolism and physiology. The central pacemaker in the suprachiasmatic nucleus (SCN) is considered hierarchically dominant over peripheral clocks, whose degree of independence, or tissue-level autonomy, has never been ascertained in vivo. Using arrhythmic Bmal1-null mice, we generated animals with reconstituted circadian expression of BMAL1 exclusively in the liver (Liver-RE). High-throughput transcriptomics and metabolomics show that the liver has independent circadian functions specific for metabolic processes such as the NAD+ salvage pathway and glycogen turnover. However, although BMAL1 occupies chromatin at most genomic targets in Liver-RE mice, circadian expression is restricted to ∼10% of normally rhythmic transcripts. Finally, rhythmic clock gene expression is lost in Liver-RE mice under constant darkness. Hence, full circadian function in the liver depends on signals emanating from other clocks, and light contributes to tissue-autonomous clock function.
2019-06-13 | GSE132659 | GEO