Identification of the suprachiasmatic nucleus in birds

2001 ◽  
Vol 280 (4) ◽  
pp. R1185-R1189 ◽  
Author(s):  
Takashi Yoshimura ◽  
Shinobu Yasuo ◽  
Yoshikazu Suzuki ◽  
Eri Makino ◽  
Yuki Yokota ◽  
...  
Keyword(s):  
Locomotor Activity ◽  
Circadian Rhythms ◽  
Circadian Clock ◽  
Suprachiasmatic Nucleus ◽  
Japanese Quail ◽  
Clock Genes ◽  
Biological Clock ◽  
Circadian Oscillators ◽  
Circadian Clock Genes ◽  
Dim Light

Circadian rhythms are generated by an internal biological clock. The suprachiasmatic nucleus (SCN) in the hypothalamus is known to be the dominant biological clock regulating circadian rhythms in mammals. In birds, two nuclei, the so-called medial SCN (mSCN) and the visual SCN (vSCN), have both been proposed to be the avian SCN. However, it remains an unsettled question which nuclei are homologous to the mammalian SCN. We have identified circadian clock genes in Japanese quail and demonstrated that these genes are expressed in known circadian oscillators, the pineal and the retina. Here, we report that these clock genes are expressed in the mSCN but not in the vSCN in Japanese quail, Java sparrow, chicken, and pigeon. In addition, mSCN lesions eliminated or disorganized circadian rhythms of locomotor activity under constant dim light, but did not eliminate entrainment under light-dark (LD) cycles in pigeon. However, the lesioned birds became completely arrhythmic even under LD after the pineal and the eye were removed. These results indicate that the mSCN is a circadian oscillator in birds.

scholarly journals Modulatory Effects of Circadian Rhythms in the Lung Adenocarcinoma Tumor Microenvironment

2021 ◽  
Author(s):  
Qianzhun Huang ◽  
Xiaoyang Su ◽  
Ning Fang ◽  
Jian Huang
Keyword(s):  
Tumor Microenvironment ◽  
Circadian Rhythms ◽  
Lung Adenocarcinoma ◽  
Circadian Clock ◽  
Drug Sensitivity ◽  
Molecular Mechanisms ◽  
Clock Genes ◽  
Functional Enrichment ◽  
Expression Levels ◽  
Circadian Clock Genes

Abstract Background: Dysregulated circadian dynamic balance is strongly associated with cancer development. However, biological functions of circadian rhythms in lung adenocarcinoma (LUAD) have not been elucidated. This study aimed at valuating the modulatory effects of circadian rhythms in the LUAD tumor microenvironment.Methods: Multiple open-source bioinformatics research platforms are used to comprehensively elucidate the expression level, prognosis, potential biological function, drug sensitivity, and immune microenvironment of circadian clock genes in LUAD.Results: Most circadian clock genes in LUAD are dysregulated and are strongly correlated with patient prognosis, and missense mutations at splicing sites of these genes. Besides, these genes are closely associated with some well-known cancer-related marker pathways, which are mainly involved in the inhibition of the Apoptosis, Cell cycle, and DNA Damage Response Pathway. Furthermore, functional enrichment analysis revealedthat circadian clock genes regulate transcription factor activities and circadian rhythms in LUAD tissues. As for drug sensitivity, high expression of CLOCK, CRY1, and NR1D2 as well as suppressedPER2 and CRY2 expression levels are associated with drug resistance. The expression levels of circadian clock genes in LUAD correlate with immune infiltration and are involved in the regulation of immunosuppression.Conclusions: Our multi-omics analysis provides a more comprehensive understanding of the molecular mechanisms of the circadian clock genes in LUAD and provides new insights for a more precise screening of prognostic biomarkers and immunotherapy.

Abolished Daily Expression Patterns of SIRT1, SIRT2, and SIRT5 in Human Chronic Myeloid Leukemia

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 4613-4613
Author(s):  
Ming-Yu Yang ◽  
Pai-Mei Lin ◽  
Jui-Feng Hsu ◽  
Wen-Chi Yang ◽  
Yi-Chang Liu ◽  
...  
Keyword(s):  
Chronic Myeloid Leukemia ◽  
Circadian Rhythms ◽  
Circadian Clock ◽  
Myeloid Leukemia ◽  
Clock Genes ◽  
Expression Patterns ◽  
Healthy Individuals ◽  
Daily Pattern ◽  
Genes Expression ◽  
Circadian Clock Genes

Abstract Abstract 4613 Circadian rhythms regulate various functions of human body and disruption of circadian rhythm has been associated with cancer development and tumor progression. Circadian clock genes use transcriptional-translational feedback loops to control circadian rhythms. Many transcriptional regulators are histone acetyltransferases (HAT) or histone deacetylases (HDAC). As clock function and integration of inputs rely on transcriptional regulation, it is possible that chromatin is remodeled during circadian cycles and in response to signals that regulate the clock. SIRT1 (sirtuin 1) is a HDAC that has recently been identified as a crucial modulator of the circadian clock machinery. To date, at least 7 SIRT genes (SIRT1–7) have been identified. In our previous report we have demonstrated the daily expression patterns of PER1, PER2, PER3, CRY1, CRY2, and CKIe in peripheral blood (PB) of healthy individuals were abolished in chronic myeloid leukemia (CML) patients and partial recoveries of daily patterns were observed in CML patients with complete cytogenetic response (CCyR) and major molecular response (MMR) post-imatinib treatment [J Biol Rhythms 2011]. In this study we further investigated the expression profiles of the 7 SIRT genes (SIRT1–7) in PB total leukocytes from 49 CML and 22 healthy volunteers. Collection of PB was carried out at four time points: 2000 h, 0200 h, 0800 h, and 1400 h, respectively. In PB total leukocytes of healthy individuals, the daily pattern of SIRT1 (p < 0.01) and SIRT5 (p < 0.05) expression level peaked at 0200 h, and SIRT2 (p < 0.01) peaked at 0800 h. Daily pattern expression of these 3 genes was abolished in newly diagnosed pre-imatinib mesylate treated and blast crisis-phase CML patients. Partial daily patterns of gene expression recoveries were observed in CML patients with CCyR and MMR. In some serial monitored individual patients, the recoveries of oscillations of SIRT1, 2, and 5 genes expression accompanied with the disappearance of BCR-ABL transcripts were also noted. The expression of SIRT3, 6, and 7 did not show a time-dependent variation among the healthy and CML patients. SIRT4 expression was undetectable both in the healthy and CML patients. Updated in vitro study results of the regulation of SIRT1, 2, and 5 genes on circadian clock genes expression will be presented at the meeting. Disclosures: No relevant conflicts of interest to declare.

Expression of circadian clock genes in retinal dopaminergic cells

2007 ◽  
Vol 24 (4) ◽  
pp. 573-580 ◽  
Author(s):  
RONALD DORENBOS ◽  
MASSIMO CONTINI ◽  
HAJIME HIRASAWA ◽  
STEFANO GUSTINCICH ◽  
ELIO RAVIOLA
Keyword(s):  
Circadian Clock ◽  
Light Adaptation ◽  
Clock Genes ◽  
Negative Control ◽  
Circadian Oscillators ◽  
Interesting Candidate ◽  
Circadian Clock Genes ◽  
Core Components ◽  
A Site

The mammalian neural retina contains single or multiple intrinsic circadian oscillators that can be directly entrained by light cycles. Dopaminergic amacrine (DA) cells represent an especially interesting candidate as a site of the retinal oscillator because of the crucial role of dopamine in light adaptation, and the widespread distribution of dopamine receptors in the retina. We hereby show by single-cell, end-point RT-PCR that retinal DA cells contain the transcripts for six core components of the circadian clock: Bmal1, Clock, Cry1, Cry2, Per1, and Per2. Rod photoreceptors represented a negative control, because they did not appear to contain clock transcripts. We finally confirmed that DA cells contain the protein encoded by the Bmal1 gene by comparing immunostaining of the nuclei of DA cells in the retinas of wildtype and Bmal1−/− mice. It is therefore likely that DA cells contain a circadian clock that anticipates predictable variations in retinal illumination.

scholarly journals Circadian Clock Genes and Photoperiodism: Comprehensive Analysis of Clock Gene Expression in the Mediobasal Hypothalamus, the Suprachiasmatic Nucleus, and the Pineal Gland of Japanese Quail under Various Light Schedules

Endocrinology ◽  
2003 ◽  
Vol 144 (9) ◽  
pp. 3742-3748 ◽  
Author(s):  
Shinobu Yasuo ◽  
Miwa Watanabe ◽  
Naritoshi Okabayashi ◽  
Shizufumi Ebihara ◽  
Takashi Yoshimura
Keyword(s):  
Pineal Gland ◽  
Circadian Clock ◽  
Suprachiasmatic Nucleus ◽  
Clock Genes ◽  
Expression Patterns ◽  
Hypothalamic Nucleus ◽  
Mediobasal Hypothalamus ◽  
Clock Gene Expression ◽  
Circadian Clock Genes ◽  
Important Center

Abstract In birds, the mediobasal hypothalamus (MBH) including the infundibular nucleus, inferior hypothalamic nucleus, and median eminence is considered to be an important center that controls the photoperiodic time measurement. Here we show expression patterns of circadian clock genes in the MBH, putative suprachiasmatic nucleus (SCN), and pineal gland, which constitute the circadian pacemaker under various light schedules. Although expression patterns of clock genes were different between long and short photoperiod in the SCN and pineal gland, the results were not consistent with those under night interruption schedule, which causes testicular growth. These results indicate that different expression patterns of the circadian clock genes in the SCN and pineal gland are not an absolute requirement for encoding and decoding of seasonal information. In contrast, expression patterns of clock genes in the MBH were stable under various light conditions, which enables animals to keep a steady-state photoinducible phase.

scholarly journals Circadian Regulation of a Drosophila Homolog of the Mammalian Clock Gene: PER and TIM Function as Positive Regulators

1998 ◽  
Vol 18 (10) ◽  
pp. 6142-6151 ◽  
Author(s):  
Kiho Bae ◽  
Choogon Lee ◽  
David Sidote ◽  
Keng-yu Chuang ◽  
Isaac Edery
Keyword(s):  
Circadian Clock ◽  
Clock Gene ◽  
Clock Genes ◽  
Temporal Regulation ◽  
Helix Loop Helix ◽  
Circadian Oscillators ◽  
Drosophila Homolog ◽  
Circadian Clock Genes ◽  
Positive Regulators

ABSTRACT The Clock gene plays an essential role in the manifestation of circadian rhythms (≅24 h) in mice and is a member of the basic helix-loop-helix (bHLH) PER-ARNT-SIM (PAS) superfamily of transcription factors. Here we report the characterization of a novelDrosophila bHLH-PAS protein that is highly homologous to mammalian CLOCK. (Similar findings were recently described by Allada et al. Cell 93:791–804, 1998, and Darlington et al., Science 280:1599–1603, 1998.) Transcripts from this putative Clockortholog (designated dClock) undergo daily rhythms in abundance that are antiphase to the cycling observed for the RNA products from the Drosophila melanogaster circadian clock genes period (per) and timeless(tim). Furthermore, dClock RNA cycling is abolished and the levels are at trough values in the absence of either PER or TIM, suggesting that these two proteins can function as transcriptional activators, a possibility which is in stark contrast to their previously characterized role in transcriptional autoinhibition. Finally, the temporal regulation of dClock expression is quickly perturbed by shifts in light-dark cycles, indicating that this molecular rhythm is closely connected to the photic entrainment pathway. The isolation of a Drosophila homolog ofClock together with the recent discovery of mammalian homologs of per indicate that there is high structural conservation in the integral components underlying circadian oscillators in Drosophila and mammals. Nevertheless, because mammalian Clock mRNA is constitutively expressed, our findings are a further example of striking differences in the regulation of putative circadian clock orthologs in different species.

scholarly journals The day/night difference in the circadian clock’s response to acute lipopolysaccharide and the rhythmic Stat3 expression in the rat suprachiasmatic nucleus

2018 ◽  
Author(s):  
Simona Moravcová ◽  
Dominika Pačesová ◽  
Barbora Melkes ◽  
Hana Kyclerová ◽  
Veronika Spišská ◽  
...  
Keyword(s):  
Locomotor Activity ◽  
Circadian Clock ◽  
Suprachiasmatic Nucleus ◽  
Clock Genes ◽  
Activity Patterns ◽  
Night Time ◽  
Male Wistar Rats ◽  
And Function ◽  
External Signals

AbstractThe circadian clock in the suprachiasmatic nucleus (SCN) regulates daily rhythms in physiology and behaviour and is an important part of the mammalian homeostatic system. Previously, we have shown that systemic inflammatory stimulation with lipopolysaccharide (LPS) induced the daytime-dependent phosphorylation of STAT3 in the SCN. Here, we demonstrate the LPS-induced Stat3 mRNA expression in the SCN and show also the circadian rhythm in Stat3 expression in the SCN, with high levels during the day. Moreover, we examined the effects of LPS (1mg/kg), applied either during the day or the night, on the rhythm in locomotor activity of male Wistar rats. We observed that recovery of normal locomotor activity patterns took longer when the animals were injected during the night. The clock genes Per1, Per2 and Nr1d1, and phosphorylation of kinases ERK1/2 and GSK3β are sensitive to external cues and function as the molecular entry for external signals into the circadian clockwork. We also studied the immediate changes in these clock genes expressions and the phosphorylation of ERK1/2 and GSK3β in the suprachiasmatic nucleus in response to daytime or night-time inflammatory stimulation. We revealed mild and transient changes with respect to the controls. Our data stress the role of STAT3 in the circadian clock response to the LPS and provide further evidence of the interaction between the circadian clock and immune system.

scholarly journals Circadian clock genes and respiratory neuroplasticity genes oscillate in the phrenic motor system

2020 ◽  
Vol 318 (6) ◽  
pp. R1058-R1067
Author(s):  
Mia N. Kelly ◽  
Danelle N. Smith ◽  
Michael D. Sunshine ◽  
Ashley Ross ◽  
Xiping Zhang ◽  
...  
Keyword(s):  
Gene Expression ◽  
Spinal Cord ◽  
Circadian Rhythms ◽  
Circadian Clock ◽  
Motor Neurons ◽  
Motor System ◽  
Molecular Mechanisms ◽  
Clock Genes ◽  
Circadian Clock Genes ◽  
Caudal Medulla

Circadian rhythms are endogenous and entrainable daily patterns of physiology and behavior. Molecular mechanisms underlie circadian rhythms, characterized by an ~24-h pattern of gene expression of core clock genes. Although it has long been known that breathing exhibits circadian rhythms, little is known concerning clock gene expression in any element of the neuromuscular system controlling breathing. Furthermore, we know little concerning gene expression necessary for specific respiratory functions, such as phrenic motor plasticity. Thus, we tested the hypotheses that transcripts for clock genes ( Bmal1, Clock, Per1, and Per2) and molecules necessary for phrenic motor plasticity ( Htr2a, Htr2b, Bdnf, and Ntrk2) oscillate in regions critical for phrenic/diaphragm motor function via RT-PCR. Tissues were collected from male Sprague-Dawley rats entrained to a 12-h light-dark cycle at 4 zeitgeber times (ZT; n = 8 rats/group): ZT5, ZT11, ZT17, and ZT23; ZT0 = lights on. Here, we demonstrate that 1) circadian clock genes ( Bmal1, Clock, Per1, and Per2) oscillate in regions critical for phrenic/diaphragm function, including the caudal medulla, ventral C3–C5 cervical spinal cord, and diaphragm; 2) the clock protein BMAL1 is localized within CtB-labeled phrenic motor neurons; 3) genes necessary for intermittent hypoxia-induced phrenic/diaphragm motor plasticity ( Htr2b and Bdnf) oscillate in the caudal medulla and ventral C3–C5 spinal cord; and 4) there is higher intensity of immunofluorescent BDNF protein within phrenic motor neurons at ZT23 compared with ZT11 ( n = 11 rats/group). These results suggest local circadian clocks exist in the phrenic motor system and confirm the potential for local circadian regulation of neuroplasticity and other elements of the neural network controlling breathing.

Circadian clock genes oscillate in human peripheral blood mononuclear cells

Blood ◽  
2003 ◽  
Vol 102 (12) ◽  
pp. 4143-4145 ◽  
Author(s):  
Diane B. Boivin ◽  
Francine O. James ◽  
Aibin Wu ◽  
Park F. Cho-Park ◽  
Huabao Xiong ◽  
...  
Keyword(s):  
Circadian Rhythms ◽  
Circadian Clock ◽  
Peripheral Blood Mononuclear Cells ◽  
Peripheral Blood ◽  
Mononuclear Cells ◽  
Clock Genes ◽  
Human Peripheral Blood ◽  
Peripheral Blood Mononuclear ◽  
Blood Mononuclear Cells ◽  
Circadian Clock Genes

Abstract In mammals, it is well documented that observable circadian rhythms are controlled by a central oscillator that is organized in transcriptional and translational feedback loops involving several clock genes. Although recent studies have demonstrated that clock genes oscillate in many peripheral tissues, their characteristics in the human immune system remain unknown. The present study investigates whether circadian clock genes function in human peripheral blood mononuclear cells. On the basis of studies derived from 3 human subjects under controlled conditions, circadian clock genes hPer1, hPer2, hPer3, and hDec1 are expressed in a circadian manner in human peripheral blood mononuclear cells (PBMCs), with the peak level occurring during the habitual time of activity. The demonstration of functional circadian machinery in human PBMCs suggests that peripheral blood cells may be useful for the investigation of human circadian rhythms and their associated disorders. (Blood. 2003;102:4143-4145)

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