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Yamamoto, Takuro; Nakahata, Yasukazu; Soma, Haruhiko; Akashi, Makoto; Mamine, Takayoshi; Takumi, Toru

doi:10.1186/1471-2199-5-18

Cited by 267 publications

(65 citation statements)

References 38 publications

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“…4). It is noteworthy that these retinal clock gene profiles were statistically significant but were generally lower in amplitude than those previously reported in the SCN and liver (36,37), similar to retinal clock gene rhythms reported for the rat (26,38). Peak-trough amplitudes ranged from 2.95-fold for Per2 in DD to 1.26-fold for Bmal1 in DD (Fig.…”

Section: Coordinate Expression Of Core Clock Genes Occurs Preferentiamentioning

confidence: 55%

Circadian organization of the mammalian retina

Ruan

Zhang

Zhou

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

148

182

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The mammalian retina contains an endogenous circadian pacemaker that broadly regulates retinal physiology and function, yet the cellular origin and organization of the mammalian retinal circadian clock remains unclear. Circadian clock neurons generate daily rhythms via cell-autonomous autoregulatory clock gene networks, and, thus, to localize circadian clock neurons within the mammalian retina, we have studied the cell type-specific expression of six core circadian clock genes in individual, identified mouse retinal neurons, as well as characterized the clock gene expression rhythms in photoreceptor degenerate rd mouse retinas. Individual photoreceptors, horizontal, bipolar, dopaminergic (DA) amacrines, catecholaminergic (CA) amacrines, and ganglion neurons were identified either by morphology or by a tyrosine hydroxylase (TH) promoter-driven red fluorescent protein (RFP) fluorescent reporter. Cells were collected, and their transcriptomes were subjected to multiplex single-cell RT-PCR for the core clock genes Period (Per) 1 and 2, Cryptochrome (Cry) 1 and 2, Clock, and Bmal1. Individual horizontal, bipolar, DA, CA, and ganglion neurons, but not photoreceptors, were found to coordinately express all six core clock genes, with the lowest proportion of putative clock cells in photoreceptors (0%) and the highest proportion in DA neurons (30%). In addition, clock gene rhythms were found to persist for >25 days in isolated, cultured rd mouse retinas in which photoreceptors had degenerated. Our results indicate that multiple types of retinal neurons are potential circadian clock neurons that express key elements of the circadian autoregulatory gene network and that the inner nuclear and ganglion cell layers of the mammalian retina contain functionally autonomous circadian clocks.circadian clock ͉ clock gene ͉ mouse retina ͉ photoreceptor ͉ real-time PCR T he mammalian retinal circadian clock exerts extensive control over retinal physiology and function, regulating a wide variety of retinal circadian rhythms, including rod disk shedding (1-3), melatonin release (4-6), dopamine synthesis (7, 8), electroretinogram (ERG) b-wave amplitude (9), extracellular pH (10), visual sensitivity (11, 12), and intraocular pressure (13,14). The retinal circadian clock and its dopamine-and melatonin-signaling molecules also influence pathological processes in the eye, including the susceptibility of photoreceptors to degeneration from light damage (15, 16), photoreceptor survival in animal models of retinal degeneration (17), and the degree of refractive errors in primate models of myopia (18). Despite its widespread influence, the cellular origin and organization of the circadian clock in the mammalian retina remain unclear.Neural circadian clocks generate endogenous circadian rhythms through cell-autonomous autoregulatory transcriptiontranslation feedback loops comprised of a defined set of ''clock genes'' in subsets of circadian pacemaker neurons. Gene targeting has demonstrated that, in mammals, the genes Period (Per) 1 and 2 and Cr...

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Section: Coordinate Expression Of Core Clock Genes Occurs Preferentiamentioning

confidence: 55%

Circadian organization of the mammalian retina

Ruan

Zhang

Zhou

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

148

182

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“…(2006) experimentally showed that mutations in the CLOCK gene PolyQ cTNR reduced the amplitude of the circadian pacemaker in mice, thereby effectively increasing the efficiency with which mice can synchronize to external light cues. The PER1 gene is a light‐sensitive core component of the circadian clock (Hunt & Sassone‐Corsi, 2007), with variability in expression allowing for entrainment of circadian rhythms in synchrony with the external environment (Yamamoto et al., 2004). Importantly, alterations in expression levels have been shown to affect phenotype (Bae et al., 2001).…”

Section: Methodsmentioning

confidence: 99%

Signatures of selection in mammalian clock genes with coding trinucleotide repeats: Implications for studying the genomics of high‐pace adaptation

Prentice

Bowman

Lalor

et al. 2017

Ecology and Evolution

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Climate change is predicted to affect the reproductive ecology of wildlife; however, we have yet to understand if and how species can adapt to the rapid pace of change. Clock genes are functional genes likely critical for adaptation to shifting seasonal conditions through shifts in timing cues. Many of these genes contain coding trinucleotide repeats, which offer the potential for higher rates of change than single nucleotide polymorphisms (SNPs) at coding sites, and, thus, may translate to faster rates of adaptation in changing environments. We characterized repeats in 22 clock genes across all annotated mammal species and evaluated the potential for selection on repeat motifs in three clock genes (NR1D1,CLOCK, and PER1) in three congeneric species pairs with different latitudinal range limits: Canada lynx and bobcat (Lynx canadensis and L. rufus), northern and southern flying squirrels (Glaucomys sabrinus and G. volans), and white‐footed and deer mouse (Peromyscus leucopus and P. maniculatus). Signatures of positive selection were found in both the interspecific comparison of Canada lynx and bobcat, and intraspecific analyses in Canada lynx. Northern and southern flying squirrels showed differing frequencies at common CLOCK alleles and a signature of balancing selection. Regional excess homozygosity was found in the deer mouse at PER1 suggesting disruptive selection, and further analyses suggested balancing selection in the white‐footed mouse. These preliminary signatures of selection and the presence of trinucleotide repeats within many clock genes warrant further consideration of the importance of candidate gene motifs for adaptation to climate change.

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“…Percent of 24-h records with abnormal circadian BP variability in normoglycemics [1][2][3][4][5][6] and prediabetics [7][8][9][10][11][12] is shown in Figure 1. Overall, 66.7% prediabetics had abnormal circadian BP variations, compared to none in normoglycemics (Po0.001) (Figure 2).…”

Section: Resultsmentioning

confidence: 99%

“…A broad spectrum of genetically anchored rhythms are built into bacteria 1 as well as humans. 2,3 Individual cells, tissues, 4 organs and organ systems all display dynamic, and partly endogenous, ultradian (less than 20 h long), circadian (20-28 h long) and even longer rhythms. Rhythmic control of blood pressure (BP) is not as well characterized as some others, such as the secretions from the endocrine glands.…”

Section: Introductionmentioning

confidence: 99%

Prediabetes is associated with abnormal circadian blood pressure variability

et al. 2008

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Blood pressure (BP) exhibits a circadian variation characterized by a morning increase, followed by a small postprandial valley and a deeper descent during nocturnal rest. Although abnormal 24-h variability (abnormal circadian variability (ACV)) predicts adverse cardiovascular disease (CVD) outcomes, a 7-day automatic ambulatory BP monitoring (ABPM) and subsequent chronobiologic analysis of the gathered data, permits identification of consistency of any abnormal circadian variation. To test whether normal overweight healthy men and women with prediabetes differed from subjects with normoglycemia in having ACV with a 7-day ABPM. Consent for a 7-day ABPM was obtained from subjects with family history of diabetes mellitus, who were participating in the screening phase for a randomized, double blind, placebo-controlled weight loss trial in prediabetics to prevent progression to diabetes mellitus. The automatic 7-day ABPM device recorded BP and heart rate every 30 min during the day and every 60 min during the night. Normoglycemic and prediabetic subjects matched for age, sex, race, BP, BMI, waist circumference and glycemic control, differed statistically significantly only in their fasting and/or 2-h postprandial serum glucose concentrations. Chronobiologically-interpreted 7-day ABPM uncovered no abnormalities in normoglycemics, whereas prediabetics had a statistically significantly higher incidence of high mean BP (MESOR-hypertension), excessive pulse pressure and/or circadian hyper-amplitude-tension (CHAT) (Po0.001). ACV detected with 7-day ABPM may account for the enhanced CVD risk in prediabetes. These findings provide a basis for larger-scale studies to assess the predictive value of 7-day ABPM over the long term.

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Cited by 267 publications

References 38 publications

Circadian organization of the mammalian retina

Circadian organization of the mammalian retina

Signatures of selection in mammalian clock genes with coding trinucleotide repeats: Implications for studying the genomics of high‐pace adaptation

Prediabetes is associated with abnormal circadian blood pressure variability

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