Forebrain oscillators ticking with different clock hands

Feillet, Céline; Mendoza, Jorge; Albrecht, Urs; Pévet, Paul; Challet, Étienne

doi:10.1016/j.mcn.2007.09.010

Cited by 134 publications

(136 citation statements)

References 64 publications

(87 reference statements)

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“…A recent study evaluated the expression of the clock genes Per1 and Per2 using mice expressing the Venus and DsRED proteins under the control of the Per1 and Per2 promoters, respectively (110). Consistent with previous observations (102), the expression of the Per1 and Per2 transgenes was only partially overlapping in various brain regions. Detailed cellular analysis in the dentate gyrus (DG), striatum, and http://doc.rero.ch cortex revealed that Per2:DsDRED is mainly observed in cells expressing glial fibrillary acidic protein (GFAP), a marker for glial cells.…”

Section: Multiple Brain Clocks: Multiple Clock Mechanisms?supporting

confidence: 73%

The Mammalian Circadian Timing System: Organization and Coordination of Central and Peripheral Clocks

Dibner¹,

Schibler

Albrecht

2010

Annu. Rev. Physiol.

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2,029

1,771

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Most physiology and behavior of mammalian organisms follow daily oscillations. These rhythmic processes are governed by environmental cues (e.g., fluctuations in light intensity and temperature), an internal circadian timing system, and the interaction between this timekeeping system and environmental signals. In mammals, the circadian timekeeping system has a complex architecture, composed of a central pacemaker in the brain's suprachiasmatic nuclei (SCN) and subsidiary clocks in nearly every body cell. The central clock is synchronized to geophysical time mainly via photic cues perceived by the retina and transmitted by electrical signals to SCN neurons. In turn, the SCN influences circadian physiology and behavior via neuronal and humoral cues and via the synchronization of local oscillators that are operative in the cells of most organs and tissues. Thus, some of the SCN output pathways serve as input pathways for peripheral tissues. Here we discuss knowledge acquired during the past few years on the complex structure and function of the mammalian circadian timing system.

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Section: Multiple Brain Clocks: Multiple Clock Mechanisms?supporting

confidence: 73%

The Mammalian Circadian Timing System: Organization and Coordination of Central and Peripheral Clocks

Dibner¹,

Schibler

Albrecht

2010

Annu. Rev. Physiol.

Self Cite

2,029

1,771

View full text Add to dashboard Cite

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“…4F). Notably, Per1 has been demonstrated to be expressed in the ARC in a manner commensurate with Gc levels (27)(28)(29)(30), and Asb4 has been found to be induced in AgRP neurons by fasting (31).…”

Section: Specific Expression Of Gr In Agrp Neuronsmentioning

confidence: 99%

Brain-Specific Homeobox Factor as a Target Selector for Glucocorticoid Receptor in Energy Balance

Lee

Kim

et al. 2013

Molecular and Cellular Biology

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e The molecular basis underlying the physiologically well-defined orexigenic function of glucocorticoid (Gc) is unclear. Brainspecific homeobox factor (Bsx) is a positive regulator of the orexigenic neuropeptide, agouti-related peptide (AgRP), in AgRP neurons of the hypothalamic arcuate nucleus. Here, we show that in response to fasting-elevated Gc levels, Gc receptor (GR) and Bsx synergize to direct activation of AgRP transcription. This synergy is dictated by unique sequence features in a novel Gc response element in AgRP (AgRP-GRE). In contrast to AgRP-GRE, Bsx suppresses transactivation directed by many conventional GREs, functioning as a gene context-dependent modulator of GR actions or a target selector for GR. Consistent with this finding, AgRP-GRE drives fasting-dependent activation of a target gene specifically in GR ؉ Bsx ؉ AgRP neurons. These results define AgRP as a common orexigenic target gene of GR and Bsx and provide an opportunity to identify their additional common targets, facilitating our understanding of the molecular basis underlying the orexigenic activity of Gc and Bsx.

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“…Measures were made in the cerebellar vermis on three slices and averaged for a given brain. Measures in the hypothalamus were performed as previously described (Feillet et al, 2008). Data were expressed as relative optical density values.…”

Section: In Situ Hybridizationmentioning

confidence: 99%

The Cerebellum Harbors a Circadian Oscillator Involved in Food Anticipation

Mendoza¹,

Pévet²,

et al. 2010

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The cerebellum participates in motor coordination as well as in numerous cerebral processes, including temporal discrimination. Animals can predict daily timing of food availability, as manifested by food-anticipatory activity under restricted feeding. By studying ex vivo clock gene expression by in situ hybridization and recording in vitro Per1-luciferase bioluminescence, we report that the cerebellum contains a circadian oscillator sensitive to feeding cues (i.e., whose clock gene oscillations are shifted in response to restricted feeding). Food-anticipatory activity was markedly reduced in mice injected intracerebroventricularly with an immunotoxin that depletes Purkinje cells (i.e., OX7-saporin). Mice bearing the hotfoot mutation (i.e., Grid2 ho/ho ) have impaired cerebellar circuitry and mild ataxic phenotype. Grid2 ho/ho mice fed ad libitum showed regular behavioral rhythms and day-night variations of clock gene expression in the hypothalamus and cerebellum. When challenged with restricted feeding, however, Grid2 ho/ho mice did not show any food-anticipatory rhythms, nor timed feeding-induced changes in cerebellar clock gene expression. In hypothalamic arcuate and dorsomedial nuclei, however, shifts in Per1 expression in response to restricted feeding were similar in cerebellar mutant and wild-type mice. Furthermore, plasma corticosterone and metabolites before mealtime did not differ between cerebellar mutant and wild-type mice. Together, these data define a role for the cerebellum in the circadian timing network and indicate that the cerebellar oscillator is required for anticipation of mealtime.

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Forebrain oscillators ticking with different clock hands

Cited by 134 publications

References 64 publications

The Mammalian Circadian Timing System: Organization and Coordination of Central and Peripheral Clocks

The Mammalian Circadian Timing System: Organization and Coordination of Central and Peripheral Clocks

Brain-Specific Homeobox Factor as a Target Selector for Glucocorticoid Receptor in Energy Balance

The Cerebellum Harbors a Circadian Oscillator Involved in Food Anticipation

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