Lability of Circadian Pacemaker Amplitude in Chick Pineal Cells: A Temperature-Dependent Process

Barrett, R. Keith; Takahashi, Joseph S.

doi:10.1177/074873049701200403

Cited by 28 publications

(20 citation statements)

References 20 publications

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“…Taken together with the results of PRC experiments and the dependence of phase shift magnitude on light intensity, the main effect of dcry over-expression is probably to suppress the phase delay. Since the amplitude of PRC becomes smaller as the total light intensity of a pulse decreases (Saunders & Thomson 1977;Keith-Barrett & Takahashi 1997), our results are inconsistent with this feature of PRC if we assume that dcry is only a circadian photoreceptor. The differences we observed are not due to the genetic background of the strains we used, nor to the insertion of the P element itself, since the flies of Act5C-GAL4/ P[UAS-dcry]#9, which over-express dcry weakly, had a light-dependence in phase shift that was similar to the wild-type (Fig.…”

Section: Discussioncontrasting

confidence: 84%

DCRY is a Drosophila photoreceptor protein implicated in light entrainment of circadian rhythm

et al. 1999

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Background : Light is the major environmental signal for the entrainment of circadian rhythms. In Drosophila melanogaster, the period(per) and timeless (tim) genes are required for circadian behavioural rhythms and their expression levels undergo circadian fluctuations. Light signals can entrain these rhythms by shifting their phases. However, little is known about the molecular mechanism for the perception and transduction of the light signal. The members of the photolyase/cryptochrome family contain flavin adenine dinucleotide (FAD) as chromophore and are involved in two diverse functions, DNA repair and photoreception of environmental light signals.

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Section: Discussioncontrasting

confidence: 84%

DCRY is a Drosophila photoreceptor protein implicated in light entrainment of circadian rhythm

et al. 1999

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“…We have confirmed that the zebrafish PAC-2 cell clock is temperature-compensated, actually decreasing the rate of its oscillation slightly when the temperature is increased, as has been reported for other cell culture model systems [7,8]. Mathematical models in which temperature influences the amplitude of the circadian pacemaker have been proposed to explain various aspects of the behavior of circadian clock outputs including their temperature compensation [33–35]. Consistently, we observe that the amplitude of circadian E-box-directed rhythmic transcription entrained by LD cycles is 6-fold higher at 30 °C than at 20 °C, while the phase remains constant.…”

Section: Discussionsupporting

confidence: 79%

“…Thus, at least in part, the ambient temperature strongly influences the amplitude of circadian rhythms of transcription, during and following entrainment by LD cycles. Such a property has been already proposed by mathematical models to explain temperature compensation of the circadian clock [33–35]. …”

Section: Resultsmentioning

confidence: 99%

Temperature Regulates Transcription in the Zebrafish Circadian Clock

et al. 2005

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It has been well-documented that temperature influences key aspects of the circadian clock. Temperature cycles entrain the clock, while the period length of the circadian cycle is adjusted so that it remains relatively constant over a wide range of temperatures (temperature compensation). In vertebrates, the molecular basis of these properties is poorly understood. Here, using the zebrafish as an ectothermic model, we demonstrate first that in the absence of light, exposure of embryos and primary cell lines to temperature cycles entrains circadian rhythms of clock gene expression. Temperature steps drive changes in the basal expression of certain clock genes in a gene-specific manner, a mechanism potentially contributing to entrainment. In the case of the per4 gene, while E-box promoter elements mediate circadian clock regulation, they do not direct the temperature-driven changes in transcription. Second, by studying E-box-regulated transcription as a reporter of the core clock mechanism, we reveal that the zebrafish clock is temperature-compensated. In addition, temperature strongly influences the amplitude of circadian transcriptional rhythms during and following entrainment by light–dark cycles, a property that could confer temperature compensation. Finally, we show temperature-dependent changes in the expression levels, phosphorylation, and function of the clock protein, CLK. This suggests a mechanism that could account for changes in the amplitude of the E-box-directed rhythm. Together, our results imply that several key transcriptional regulatory elements at the core of the zebrafish clock respond to temperature.

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“…Our amplitude and entrainment findings may be linked. It has been reported previously that low-amplitude rhythms entrain to temperature stimuli more readily than high-amplitude rhythms [25]. In this way, the lower-amplitude rhythms in BD cells under temperature cycles may shorten the period more readily.…”

Section: Discussionmentioning

confidence: 85%

Entrainment of Circadian Rhythms to Temperature Reveals Amplitude Deficits in Fibroblasts from Patients with Bipolar Disorder and Possible Links to Calcium Channels

et al. 2019

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Bipolar disorder (BD) is characterized by recurrent mood episodes, and circadian rhythm disturbances. Past studies have identified calcium channel genes as risk loci for BD. CACNA1C encodes an L-type calcium channel (LTCC) involved in the entrainment of circadian rhythms to light. Another calcium channel, i.e., the ryanodine receptor (RYR), is involved in circadian phase delays. It is unknown whether variants in CACNA1C or other calcium channels contribute to the circadian phenotype in BD. We hypothesized that, by using temperature cycles, we could model circadian entrainment in fibroblasts from BD patients and controls to interrogate the circadian functions of LTCCs. Using Per2-luc, a bioluminescent reporter, we verified that cells entrain to temperature rhythms in vitro. Under constant temperature conditions, the LTCC antagonist verapamil shortened the circadian period, and the RYR antagonist dantrolene lengthened the period. However, neither drug affected temperature entrainment. Fibroblasts from BD patients and controls also entrained to temperature. In cells from BD patients, the rhythm amplitude was lower under entrained, but not constant, conditions. Temperature entrainment was otherwise similar between BD and control cells. However, the CACNA1C genotype among BD cells predicted the degree to which cells entrained. We conclude that assessment of rhythms under entrained conditions reveals additional rhythm abnormalities in BD that are not observable under constant temperature conditions.

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Lability of Circadian Pacemaker Amplitude in Chick Pineal Cells: A Temperature-Dependent Process

Cited by 28 publications

References 20 publications

DCRY is a Drosophila photoreceptor protein implicated in light entrainment of circadian rhythm

DCRY is a Drosophila photoreceptor protein implicated in light entrainment of circadian rhythm

Temperature Regulates Transcription in the Zebrafish Circadian Clock

Entrainment of Circadian Rhythms to Temperature Reveals Amplitude Deficits in Fibroblasts from Patients with Bipolar Disorder and Possible Links to Calcium Channels

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