A Receptor-type Guanylyl Cyclase Expression Is Regulated under Circadian Clock in Peripheral Tissues of the Silk Moth

The mechanisms by which the circadian clock controls behavior through regulating gene expression in peripheral tissues are largely unknown. Here we demonstrate that the expression of a receptor-type guanylyl cyclase (BmGC-I) from the silk mothBombyx moriis regulated in the flight muscles in a circadian fashion.BmGC-ImRNA was expressed from the end of the light period through the middle of the dark period. BmGC-I protein expression and cGMP levels were high around the initiation of eclosion events at the beginning of the photoperiod. The rhythm of theBmGC-Iand cGMP levels free-ran in constant light and synchronized to the environmental photoperiodic cycle. The circadian regulation of BmGC-I expression was also observed in the legs but not in other tissues examined. BmGC-I therefore represents a circadian output gene that regulates eclosion behavior.

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Temporal profile of circadian clock gene expression in a transplanted suprachiasmatic nucleus and peripheral tissues

European Journal of Neuroscience ◽

10.1111/j.1460-9568.2007.05926.x ◽

2007 ◽

Vol 26 (10) ◽

pp. 2731-2738 ◽

Cited By ~ 9

Author(s):

Mitsugu Sujino ◽

Mamoru Nagano ◽

Atsuko Fujioka ◽

Yasufumi Shigeyoshi ◽

Shin-Ichi T. Inouye

Keyword(s):

Gene Expression ◽

Circadian Clock ◽

Suprachiasmatic Nucleus ◽

Clock Gene ◽

Circadian Clock Gene ◽

Peripheral Tissues ◽

Temporal Profile ◽

Clock Gene Expression

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Metabolic homeostasis: it’s all in the timing

Endocrinology ◽

10.1210/endocr/bqab199 ◽

2021 ◽

Author(s):

Patricia L Brubaker ◽

Alexandre Martchenko

Keyword(s):

Metabolic Disease ◽

Circadian Clock ◽

Pancreatic Beta Cell ◽

Critical Role ◽

Gut Hormones ◽

Circadian Regulation ◽

Metabolic Homeostasis ◽

Peripheral Tissues ◽

Brown Adipose ◽

Positive And Negative Feedback

Abstract Cross-talk between peripheral tissues is essential to ensure the coordination of nutrient intake with disposition during the feeding period, thereby preventing metabolic disease. This Mini-review considers the interactions between the key peripheral tissues that constitute the metabolic clock, each of which is considered in a separate Mini-review in this collation of articles published in Endocrinology in 2020/2021, by: Martchenko et al. (Circadian Rhythms and the Gastrointestinal Tract: Relationship to Metabolism and Gut Hormones); Alvarez et al. (The Microbiome as a Circadian Coordinator of Metabolism); Seshadri et al. (Circadian Regulation of the Pancreatic Beta Cell); McCommis et al. (The Importance of Keeping Time in the Liver); Oosterman et al. (The Circadian Clock, Shift Work, and Tissue-Specific Insulin Resistance); and Heyde et al. (Contributions of White and Brown Adipose Tissues to the Circadian Regulation of Energy Metabolism). The use of positive- and negative-feedback signals, both hormonal and metabolic, between these tissues ensures that peripheral metabolic pathways are synchronized with the timing of food intake, thus optimizing nutrient disposition and preventing metabolic disease. Collectively, these articles highlight the critical role played by the circadian clock in the maintenance of metabolic homeostasis.

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Diurnal Regulation of Cellular Processes in the Cyanobacterium Synechocystis sp. Strain PCC 6803: Insights from Transcriptomic, Fluxomic, and Physiological Analyses

mBio ◽

10.1128/mbio.00464-16 ◽

2016 ◽

Vol 7 (3) ◽

Cited By ~ 44

Author(s):

Rajib Saha ◽

Deng Liu ◽

Allison Hoynes-O’Connor ◽

Michelle Liberton ◽

Jingjie Yu ◽

...

Keyword(s):

Gene Expression ◽

Dark Period ◽

Expression Patterns ◽

Light Period ◽

Transcriptional Analysis ◽

Transcriptional Networks ◽

Diurnal Changes ◽

Cellular Processes ◽

Diurnal Behavior ◽

Pcc 6803

ABSTRACT Synechocystis sp. strain PCC 6803 is the most widely studied model cyanobacterium, with a well-developed omics level knowledgebase. Like the lifestyles of other cyanobacteria, that of Synechocystis PCC 6803 is tuned to diurnal changes in light intensity. In this study, we analyzed the expression patterns of all of the genes of this cyanobacterium over two consecutive diurnal periods. Using stringent criteria, we determined that the transcript levels of nearly 40% of the genes in Synechocystis PCC 6803 show robust diurnal oscillating behavior, with a majority of the transcripts being upregulated during the early light period. Such transcripts corresponded to a wide array of cellular processes, such as light harvesting, photosynthetic light and dark reactions, and central carbon metabolism. In contrast, transcripts of membrane transporters for transition metals involved in the photosynthetic electron transport chain (e.g., iron, manganese, and copper) were significantly upregulated during the late dark period. Thus, the pattern of global gene expression led to the development of two distinct transcriptional networks of coregulated oscillatory genes. These networks help describe how Synechocystis PCC 6803 regulates its metabolism toward the end of the dark period in anticipation of efficient photosynthesis during the early light period. Furthermore, in silico flux prediction of important cellular processes and experimental measurements of cellular ATP, NADP(H), and glycogen levels showed how this diurnal behavior influences its metabolic characteristics. In particular, NADPH/NADP + showed a strong correlation with the majority of the genes whose expression peaks in the light. We conclude that this ratio is a key endogenous determinant of the diurnal behavior of this cyanobacterium. IMPORTANCE Cyanobacteria are photosynthetic microbes that use energy from sunlight and CO 2 as feedstock. Certain cyanobacterial strains are amenable to facile genetic manipulation, thus enabling synthetic biology and metabolic engineering applications. Such strains are being developed as a chassis for the sustainable production of food, feed, and fuel. To this end, a holistic knowledge of cyanobacterial physiology and its correlation with gene expression patterns under the diurnal cycle is warranted. In this report, a genomewide transcriptional analysis of Synechocystis PCC 6803, the most widely studied model cyanobacterium, sheds light on the global coordination of cellular processes during diurnal periods. Furthermore, we found that, in addition to light, the redox level of NADP(H) is an important endogenous regulator of diurnal entrainment of Synechocystis PCC 6803.

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Hypothermia modulates circadian clock gene expression in lizard peripheral tissues

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.00370.2006 ◽

2007 ◽

Vol 292 (1) ◽

pp. R160-R166 ◽

Cited By ~ 13

Author(s):

Daniela Vallone ◽

Elena Frigato ◽

Cristiano Vernesi ◽

Augusto Foà ◽

Nicholas S. Foulkes ◽

...

Keyword(s):

Gene Expression ◽

Circadian Clock ◽

Low Temperatures ◽

Clock Gene ◽

Molecular Mechanisms ◽

Constant Darkness ◽

Podarcis Sicula ◽

Peripheral Tissues ◽

Clock Gene Expression ◽

Close Phylogenetic Relationship

The molecular mechanisms whereby the circadian clock responds to temperature changes are poorly understood. The ruin lizard Podarcis sicula has historically proven to be a valuable vertebrate model for exploring the influence of temperature on circadian physiology. It is an ectotherm that naturally experiences an impressive range of temperatures during the course of the year. However, no tools have been available to dissect the molecular basis of the clock in this organism. Here, we report the cloning of three lizard clock gene homologs ( Period2, Cryptochrome1, and Clock) that have a close phylogenetic relationship with avian clock genes. These genes are expressed in many tissues and show a rhythmic expression profile at 29°C in light-dark and constant darkness lighting conditions, with phases comparable to their mammalian and avian counterparts. Interestingly, we show that at low temperatures (6°C), cycling clock gene expression is attenuated in peripheral clocks with a characteristic increase in basal expression levels. We speculate that this represents a conserved vertebrate clock gene response to low temperatures. Furthermore, these results bring new insight into the issue of whether circadian clock function is compatible with hypothermia.

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Chronobiology and Metabolism: Is Ketogenic Diet Able to Influence Circadian Rhythm?

Frontiers in Neuroscience ◽

10.3389/fnins.2021.756970 ◽

2021 ◽

Vol 15 ◽

Author(s):

Elena Gangitano ◽

Lucio Gnessi ◽

Andrea Lenzi ◽

David Ray

Keyword(s):

Gene Expression ◽

Circadian Rhythm ◽

Circadian Clock ◽

Ketogenic Diet ◽

Clock Genes ◽

The Body ◽

Acid Oxidation ◽

Metabolic Switch ◽

Peripheral Tissues ◽

Central Clock

Circadian rhythms underpin most physiological processes, including energy metabolism. The core circadian clock consists of a transcription-translation negative feedback loop, and is synchronized to light-dark cycles by virtue of light input from the retina, to the central clock in the suprachiasmatic nucleus in the hypothalamus. All cells in the body have circadian oscillators which are entrained to the central clock by neural and humoral signals. In addition to light entrainment of the central clock in the brain, it now emerges that other stimuli can drive circadian clock function in peripheral tissues, the major one being food. This can then drive the liver clock to be misaligned with the central brain clock, a situation of internal misalignment with metabolic disease consequences. Such misalignment is prevalent, with shift workers making up 20% of the working population. The effects of diet composition on the clock are not completely clarified yet. High-fat diet and fasting influence circadian expression of clock genes, inducing phase-advance and phase-delay in animal models. Ketogenic diet (KD) is able to induce a metabolic switch from carbohydrate to fatty acid oxidation, miming a fasting state. In recent years, some animal studies have been conducted to investigate the ability of the KD to modify circadian gene expression, and demonstrated that the KD alters circadian rhythm and induces a rearrangement of metabolic gene expression. These findings may lead to new approaches to obesity and metabolic pathologies treatment.

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Immunocytochemical studies on the behavior of RuBisCO and LHCP II during the cell cycle of synchronized Euglena gracilis

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100160868 ◽

1990 ◽

Vol 48 (3) ◽

pp. 662-663

Author(s):

Tetsuaki Osafune ◽

Shuji Sumida ◽

Tomoko Ehara ◽

Eiji Hase ◽

Jerome A. Schiff

Keyword(s):

Cell Cycle ◽

Immunoelectron Microscopy ◽

Growth Phase ◽

Euglena Gracilis ◽

Dark Period ◽

Light Period ◽

Carboxylase Activity ◽

Immunocytochemical Studies ◽

Lhcp Ii

Changes in the morphology of pyrenoid and the distribution of RuBisCO in the chloroplast of Euglena gracilis were followed by immunoelectron microscopy during the cell cycle in a light (14 h)- dark (10 h) synchronized culture under photoautotrophic conditions. The imrnunoreactive proteins wereconcentrated in the pyrenoid, and less densely distributed in the stroma during the light period (growth phase, Fig. 1-2), but the pyrenoid disappeared during the dark period (division phase), and RuBisCO was dispersed throughout the stroma. Toward the end of the division phase, the pyrenoid began to form in the center of the stroma, and RuBisCO is again concentrated in that pyrenoid region. From a comparison of photosynthetic CO2-fixation with the total carboxylase activity of RuBisCO extracted from Euglena cells in the growth phase, it is suggested that the carboxylase in the pyrenoid functions in CO2-fixation in photosynthesis.

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