scholarly journals Post-Translational Mechanisms of Plant Circadian Regulation

Genes ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 325
Author(s):  
Jiapei Yan ◽  
Yeon Jeong Kim ◽  
David E. Somers
Keyword(s):  
Circadian Rhythms ◽  
Recent Work ◽  
Transcriptional Control ◽  
Circadian System ◽  
Circadian Oscillator ◽  
Circadian Regulation ◽  
Circadian Control ◽  
Wide Range ◽  
Molecular Components ◽  
Translational Mechanisms

The molecular components of the circadian system possess the interesting feature of acting together to create a self-sustaining oscillator, while at the same time acting individually, and in complexes, to confer phase-specific circadian control over a wide range of physiological and developmental outputs. This means that many circadian oscillator proteins are simultaneously also part of the circadian output pathway. Most studies have focused on transcriptional control of circadian rhythms, but work in plants and metazoans has shown the importance of post-transcriptional and post-translational processes within the circadian system. Here we highlight recent work describing post-translational mechanisms that impact both the function of the oscillator and the clock-controlled outputs.

scholarly journals A high-throughput delayed fluorescence method reveals underlying differences in the control of circadian rhythms inTriticum aestivumandBrassica napus

2019 ◽  
Author(s):  
Hannah Rees ◽  
Susan Duncan ◽  
Peter Gould ◽  
Rachel Wells ◽  
Mark Greenwood ◽  
...  
Keyword(s):  
Circadian Rhythms ◽  
High Throughput ◽  
Delayed Fluorescence ◽  
Crop Plants ◽  
Growth And Yield ◽  
Constant Darkness ◽  
Competitive Growth ◽  
Representative Sampling ◽  
Circadian Control ◽  
Wide Range

AbstractBackgroundA robust circadian clock has been implicated in plant resilience, resource-use efficiency, competitive growth and yield. A huge number of physiological processes are under circadian control in plants including: responses to biotic and abiotic stresses; flowering time; plant metabolism; and mineral uptake. Understanding how the clock functions in crops such asTriticum aestivum(bread wheat) andBrassica napus(oilseed rape) therefore has great agricultural potential. Delayed fluorescence (DF) imaging has been shown to be applicable to a wide range of plant species and requires no genetic transformation. Although DF has been used to measure period length of both mutants and wild ecotypes ofArabidopsis, this assay has never been systematically optimised for crop plants. The physical size of bothB. napusandT. aestivumled us to develop a representative sampling strategy which enables high-throughput imaging of these crops.ResultsIn this study, we describe the plant-specific optimisation of DF imaging to obtain reliable circadian phenotypes with the robustness and reproducibility to detect diverging periods between cultivars of the same species. We find that the age of plant material, light regime and temperature conditions all significantly effect DF rhythms and describe the optimal conditions for measuring robust rhythms in each species. We also show that sections of leaf can be used to obtain period estimates with improved throughput for larger sample size experiments.ConclusionsWe present an optimized protocol for high-throughput phenotyping of circadian period specific to two economically valuable crop plants. Application of this method revealed significant differences between the periods of several widely grown elite cultivars. This method also identified intriguing differential responses of circadian rhythms inT. aestivumcompared toB. napus; specifically the dramatic change to rhythm robustness when plants were imaged under constant light versus constant darkness. This points towards diverging networks underling circadian control in these two species.

scholarly journals Circadian regulation of lipid metabolism

2016 ◽  
Vol 75 (4) ◽  
pp. 440-450 ◽  
Author(s):  
Joshua J Gooley
Keyword(s):  
Lipid Metabolism ◽  
Energy Metabolism ◽  
Circadian Rhythms ◽  
Metabolic Pathways ◽  
Circadian System ◽  
Lipid Absorption ◽  
Acid Oxidation ◽  
Circadian Regulation ◽  
Peripheral Tissues ◽  
Lipid Species

The circadian system temporally coordinates daily rhythms in feeding behaviour and energy metabolism. The objective of the present paper is to review the mechanisms that underlie circadian regulation of lipid metabolic pathways. Circadian rhythms in behaviour and physiology are generated by master clock neurons in the suprachiasmatic nucleus (SCN). The SCN and its efferent targets in the hypothalamus integrate light and feeding signals to entrain behavioural rhythms as well as clock cells located in peripheral tissues, including the liver, adipose tissue and muscle. Circadian rhythms in gene expression are regulated at the cellular level by a molecular clock comprising a core set of clock genes/proteins. In peripheral tissues, hundreds of genes involved in lipid biosynthesis and fatty acid oxidation are rhythmically activated and repressed by clock proteins, hence providing a direct mechanism for circadian regulation of lipids. Disruption of clock gene function results in abnormal metabolic phenotypes and impaired lipid absorption, demonstrating that the circadian system is essential for normal energy metabolism. The composition and timing of meals influence diurnal regulation of metabolic pathways, with food intake during the usual rest phase associated with dysregulation of lipid metabolism. Recent studies using metabolomics and lipidomics platforms have shown that hundreds of lipid species are circadian-regulated in human plasma, including but not limited to fatty acids, TAG, glycerophospholipids, sterol lipids and sphingolipids. In future work, these lipid profiling approaches can be used to understand better the interaction between diet, mealtimes and circadian rhythms on lipid metabolism and risk for obesity and metabolic diseases.

scholarly journals Disruption of Circadian Rhythms: A Crucial Factor in the Etiology of Depression

2011 ◽  
Vol 2011 ◽  
pp. 1-9 ◽  
Author(s):  
Roberto Salgado-Delgado ◽  
Araceli Tapia Osorio ◽  
Nadia Saderi ◽  
Carolina Escobar
Keyword(s):  
Circadian Rhythms ◽  
Biological Clock ◽  
Therapeutic Strategies ◽  
Circadian System ◽  
Metabolic Functions ◽  
Lighting Conditions ◽  
Wide Range ◽  
Close Relationship ◽  
And Behavior ◽  
Depressive States

Circadian factors might play a crucial role in the etiology of depression. It has been demonstrated that the disruption of circadian rhythms by lighting conditions and lifestyle predisposes individuals to a wide range of mood disorders, including impulsivity, mania and depression. Also, associated with depression, there is the impairment of circadian rhythmicity of behavioral, endocrine, and metabolic functions. Inspite of this close relationship between both processes, the complex relationship between the biological clock and the incidence of depressive symptoms is far from being understood. The efficiency and the timing of treatments based on chronotherapy (e.g., light treatment, sleep deprivation, and scheduled medication) indicate that the circadian system is an essential target in the therapy of depression. The aim of the present review is to analyze the biological and clinical data that link depression with the disruption of circadian rhythms, emphasizing the contribution of circadian desynchrony. Therefore, we examine the conditions that may lead to circadian disruption of physiology and behavior as described in depressive states, and, according to this approach, we discuss therapeutic strategies aimed at treating the circadian system and depression.

9. Evolution and another look at the clock

2017 ◽  
pp. 122-130
Author(s):  
Russell G. Foster ◽  
Leon Kreitzman
Keyword(s):  
Circadian Rhythms ◽  
Empirical Evidence ◽  
Clock Genes ◽  
Internal Clock ◽  
Circadian System ◽  
Mrna Levels ◽  
Vital Importance ◽  
Living Things ◽  
History Of ◽  
Molecular Components

‘Evolution and another look at the clock’ concludes that the circadian system controls every key aspect of biochemistry, physiology, and behaviour. All plants, fungi, protista, algae, invertebrates, vertebrates, cyanobacteria, and at least one archaeon display circadian rhythms. These rhythms have many molecular components conserved between diverse species and are thought to be generated by molecular transcription–translation feedback loops in which a group of core clock genes regulate each other to ensure that their mRNA levels oscillate with a period of approximately 24 hours. Although the empirical evidence has been difficult to demonstrate, there is a consensus that the internal clock has been of vital importance in the evolutionary history of living things.

scholarly journals Superoxide is promoted by sucrose and affects amplitude of circadian rhythms in the evening

2021 ◽  
Vol 118 (10) ◽  
pp. e2020646118
Author(s):  
Ángela Román ◽  
Xiang Li ◽  
Dongjing Deng ◽  
John W. Davey ◽  
Sally James ◽  
...  
Keyword(s):  
Circadian Rhythms ◽  
Transcriptional Control ◽  
Transcriptional Response ◽  
Biological Rhythms ◽  
Circadian Oscillator ◽  
Environmental Cues ◽  
Growth Responses ◽  
Carbon Availability ◽  
Photosynthetic Metabolism ◽  
Metabolic Signal

Plants must coordinate photosynthetic metabolism with the daily environment and adapt rhythmic physiology and development to match carbon availability. Circadian clocks drive biological rhythms which adjust to environmental cues. Products of photosynthetic metabolism, including sugars and reactive oxygen species (ROS), are closely associated with the plant circadian clock, and sugars have been shown to provide metabolic feedback to the circadian oscillator. Here, we report a comprehensive sugar-regulated transcriptome of Arabidopsis and identify genes associated with redox and ROS processes as a prominent feature of the transcriptional response. We show that sucrose increases levels of superoxide (O2–), which is required for transcriptional and growth responses to sugar. We identify circadian rhythms of O2–-regulated transcripts which are phased around dusk and find that O2– is required for sucrose to promote expression of TIMING OF CAB1 (TOC1) in the evening. Our data reveal a role for O2– as a metabolic signal affecting transcriptional control of the circadian oscillator in Arabidopsis.

Disrupted circadian rhythms in VIP- and PHI-deficient mice

2003 ◽  
Vol 285 (5) ◽  
pp. R939-R949 ◽  
Author(s):  
Christopher S. Colwell ◽  
Stephan Michel ◽  
Jason Itri ◽  
Williams Rodriguez ◽  
J. Tam ◽  
...  
Keyword(s):  
Circadian Rhythms ◽  
Wheel Running ◽  
Activity Rhythm ◽  
Activity Patterns ◽  
Circadian System ◽  
Diurnal Rhythms ◽  
Constant Darkness ◽  
Light Cycle ◽  
Wild Type ◽  
Deficient Mice

The related neuropeptides vasoactive intestinal peptide (VIP) and peptide histidine isoleucine (PHI) are expressed at high levels in the neurons of the suprachiasmatic nucleus (SCN), but their function in the regulation of circadian rhythms is unknown. To study the role of these peptides on the circadian system in vivo, a new mouse model was developed in which both VIP and PHI genes were disrupted by homologous recombination. In a light-dark cycle, these mice exhibited diurnal rhythms in activity which were largely indistinguishable from wild-type controls. In constant darkness, the VIP/PHI-deficient mice exhibited pronounced abnormalities in their circadian system. The activity patterns started ∼8 h earlier than predicted by the previous light cycle. In addition, lack of VIP/PHI led to a shortened free-running period and a loss of the coherence and precision of the circadian locomotor activity rhythm. In about one-quarter of VIP/PHI mice examined, the wheel-running rhythm became arrhythmic after several weeks in constant darkness. Another striking example of these deficits is seen in the split-activity patterns expressed by the mutant mice when they were exposed to a skeleton photoperiod. In addition, the VIP/PHI-deficient mice exhibited deficits in the response of their circadian system to light. Electrophysiological analysis indicates that VIP enhances inhibitory synaptic transmission within the SCN of wild-type and VIP/PHI-deficient mice. Together, the observations suggest that VIP/PHI peptides are critically involved in both the generation of circadian oscillations as well as the normal synchronization of these rhythms to light.

scholarly journals Cryptochromes regulate IGF-1 production and signaling through control of JAK2-dependent STAT5B phosphorylation

2017 ◽  
Vol 28 (6) ◽  
pp. 834-842 ◽  
Author(s):  
Amol Chaudhari ◽  
Richa Gupta ◽  
Sonal Patel ◽  
Nikkhil Velingkaar ◽  
Roman Kondratov
Keyword(s):  
Circadian Rhythms ◽  
Circadian Clock ◽  
Skeletal Muscles ◽  
Cancer Metabolism ◽  
Reduced Body ◽  
Circadian Control ◽  
Cell Growth And Proliferation ◽  
Deficient Mice ◽  
Igf Signaling

Insulin-like growth factor (IGF) signaling plays an important role in cell growth and proliferation and is implicated in regulation of cancer, metabolism, and aging. Here we report that IGF-1 level in blood and IGF-1 signaling demonstrates circadian rhythms. Circadian control occurs through cryptochromes (CRYs)—transcriptional repressors and components of the circadian clock. IGF-1 rhythms are disrupted in Cry-deficient mice, and IGF-1 level is reduced by 80% in these mice, which leads to reduced IGF signaling. In agreement, Cry-deficient mice have reduced body (∼30% reduction) and organ size. Down-regulation of IGF-1 upon Cry deficiency correlates with reduced Igf-1 mRNA expression in the liver and skeletal muscles. Igf-1 transcription is regulated through growth hormone–induced, JAK2 kinase–mediated phosphorylation of transcriptional factor STAT5B. The phosphorylation of STAT5B on the JAK2-dependent Y699 site is significantly reduced in the liver and skeletal muscles of Cry-deficient mice. At the same time, phosphorylation of JAK2 kinase was not reduced upon Cry deficiency, which places CRY activity downstream from JAK2. Thus CRYs link the circadian clock and JAK-STAT signaling through control of STAT5B phosphorylation, which provides the mechanism for circadian rhythms in IGF signaling in vivo.

Light-induced suppression of the rat circadian system

1995 ◽  
Vol 268 (5) ◽  
pp. R1111-R1116 ◽  
Author(s):  
P. Depres-Brummer ◽  
F. Levi ◽  
G. Metzger ◽  
Y. Touitou
Keyword(s):  
Locomotor Activity ◽  
Body Temperature ◽  
Circadian Rhythms ◽  
Prolonged Exposure ◽  
Light Exposure ◽  
Continuous Light ◽  
Circadian System ◽  
Short Exposure ◽  
Complete Suppression ◽  
Continuous Darkness

In a constant environment, circadian rhythms persist with slightly altered period lengths. Results of studies with continuous light exposure are less clear, because of short exposure durations and single-variable monitoring. This study sought to characterize properties of the oscillator(s) controlling the rat's circadian system by monitoring both body temperature and locomotor activity. We observed that prolonged exposure of male Sprague-Dawley rats to continuous light (LL) systematically induced complete suppression of body temperature and locomotor activity circadian rhythms and their replacement by ultradian rhythms. This was preceded by a transient loss of coupling between both functions. Continuous darkness (DD) restored circadian synchronization of temperature and activity circadian rhythms within 1 wk. The absence of circadian rhythms in LL coincided with a mean sixfold decrease in plasma melatonin and a marked dampening but no abolition of its circadian rhythmicity. Restoration of temperature and activity circadian rhythms in DD was associated with normalization of melatonin rhythm. These results demonstrated a transient internal desynchronization of two simultaneously monitored functions in the rat and suggested the existence of two or more circadian oscillators. Such a hypothesis was further strengthened by the observation of a circadian rhythm in melatonin, despite complete suppression of body temperature and locomotor activity rhythms. This rat model should be useful for investigating the physiology of the circadian timing system as well as to identify agents and schedules having specific pharmacological actions on this system.

scholarly journals Timing metabolism in cartilage and bone: links between circadian clocks and tissue homeostasis

2019 ◽  
Vol 243 (3) ◽  
pp. R29-R46 ◽  
Author(s):  
Cátia F Gonçalves ◽  
Qing-Jun Meng
Keyword(s):  
Rheumatoid Arthritis ◽  
Circadian Rhythms ◽  
Circadian System ◽  
Tissue Homeostasis ◽  
Circadian Clocks ◽  
Clock System ◽  
Metabolic Functions ◽  
Biochemical Mechanisms ◽  
Skeletal Disorders ◽  
Bone Physiology

The circadian system in mammals is responsible for the temporal coordination of multiple physiological and behavioural processes that are necessary for homeostasis. In the skeleton, it has long been known that metabolic functions of chondrocytes, osteoblasts and osteoclasts exhibit intrinsic circadian rhythms. In addition, results from animal models reveal a close connection between the disruption of circadian rhythms and skeletal disorders such as rheumatoid arthritis, osteoarthritis and osteoporosis. In this review, we summarise the latest insights into the genetic and biochemical mechanisms linking cartilage and bone physiology to the circadian clock system. We also discuss how this knowledge can be utilised to improve human health.

Evolution Analysis of the Circadian Clock Protein KaiB

2013 ◽  
Vol 647 ◽  
pp. 391-395
Author(s):  
Liu Sen ◽  
Song Liu
Keyword(s):  
Circadian Rhythms ◽  
Circadian Clock ◽  
Feedback Loop ◽  
Circadian System ◽  
Circadian Rhythmicity ◽  
Physiological Functions ◽  
Clock System ◽  
Evolution Analysis ◽  
Clock Protein

Regulation of daily physiological functions with approximate a 24-hour periodicity, or circadian rhythms, is a characteristic of eukaryotes. So far, cyanobacteria are only known prokaryotes reported to possess circadian rhythmicity. The circadian system in cyanobacteria comprises both a post-translational oscillator (PTO) and a transcriptional/translational feedback loop (TTFL). The PTO can be reconstituted in vitro with three purified proteins (KaiA, KaiB, and KaiC) with the existence of ATP. Phase of the nanoclockwork has been associated with the phosphorylation states of KaiC, with KaiA promoting the phosphorylation of KaiC, and KaiB de-phosphorylating KaiC. Here we studied the evolution of the KaiB protein. The result will be helpful in understanding the evolution of the circadian clock system.

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