Development of a circadian melatonin rhythm in embryonic zebrafish

Kazimi, Nasser; Cahill, Gregory M.

doi:10.1016/s0165-3806(99)00096-6

Cited by 128 publications

(103 citation statements)

References 29 publications

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“…These differences in the number of required light͞dark cycles may be attributed to the difference in monitoring of peripheral clock function (23,24,34), as opposed to central clock function in the current study. This finding is supported by previous studies in which the development of pineal rhythms was found to require only one light pulse (25,26).…”

Section: Discussionsupporting

confidence: 88%

“…The earliest detected rhythms are those of the developing photoreceptive pineal gland. Exposure of zebrafish embryos to light after the pineal gland is formed facilitates the development of clockcontrolled rhythms of melatonin and zfaanat2 mRNA in the pineal gland (25,26). Interestingly however, it has been recently shown that zebrafish embryos are light responsive at an earlier developmental stage, even before the pineal gland is formed (27).…”

Section: Resultsmentioning

confidence: 99%

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Circadian time-keeping during early stages of development

Ziv¹,

Gothilf

2006

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

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The zebrafish pineal gland is a photoreceptive organ containing an intrinsic central circadian oscillator, which drives daily rhythms of gene expression and the melatonin hormonal signal. Here we investigated the effect of light, given at early developmental stages before pineal gland formation, on the pineal circadian oscillator. Embryos that were exposed to light at 0 -6, 10 -13, or 10 -16 h after fertilization exhibited clock-controlled rhythms of arylalkylamine-N-acetyltransferase (zfaanat2) mRNA in the pineal gland during the third and fourth day of development. This rhythm was absent in embryos that were placed in continuous dark within 2 h after fertilization (before blastula stage). Differences in the phases of these rhythms indicate that they are determined by the time of illumination. Light treatments at these stages also caused a transient increase in period2 mRNA levels, and the development of zfaanat2 mRNA rhythm was abolished by PERIOD2 knock-down. These results indicate that light exposure at early developmental stages, and light-induced expression of period2, are both required for setting the phase of the circadian clock. The 24-h rhythm is then maintained throughout rapid proliferation and, remarkably, differentiation.AANAT ͉ light ͉ period2 ͉ pineal ͉ zebrafish

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Section: Discussionsupporting

confidence: 88%

Section: Resultsmentioning

confidence: 99%

Circadian time-keeping during early stages of development

Ziv¹,

Gothilf

2006

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

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“…(58) Finally, when embryos are placed in constant darkness prior to 20 hours PF, no discernable oscillations in melatonin synthesis are observed. (52) This demonstrates that there is no timed developmental event, in the absence of environmental signals, that sets melatonin rhythms. Through the use of automated video imaging analysis systems and infrared movement detectors, activity rhythms in zebrafish can be accurately monitored.…”

Section: Clock Moleculesmentioning

confidence: 98%

“…It has been shown that the development of light-entrainable circadian oscillations in melatonin occurs in the zebrafish as early as 26 hours postfertilization (PF). (52) This suggests that initial light-responsive rhythms in melatonin synthesis are generated by the pineal gland and not the retina. The pineal gland forms around 20 hours PF and expresses photoreceptor-specific markers by 24 hours PF.…”

Section: Clock Moleculesmentioning

confidence: 99%

Unraveling the mechanisms of the vertebrate circadian clock: zebrafish may light the way

Pando

Sassone–Corsi

2002

BioEssays

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Most organisms display oscillations of approximately 24 hours in their physiology. In higher organisms, these circadian oscillations in biochemical and physiological processes ultimately control complex behavioral rhythms that allow an organism to thrive in its natural habitat. Daily and seasonal light cycles are mainly responsible for keeping the circadian system properly aligned with the environment. The molecular mechanisms responsible for the control of the circadian clock have been explored in a number of systems. Interestingly, the circadian oscillations that are responsive to environmental stimuli are present very early during development. This review focuses on the advantages of using the zebrafish to study the development of the vertebrate circadian system and light-dependent signaling to the clock.

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“…Zebrafish exhibit circadian rhythms of behavior as larvae and as adults, Delaunay et al, 2000;Hurd et al, 1998;Kazimi & Cahill, 1999) with peaks of behavioral activity during the daytime. Oscillators within the brain presumably drive these rhythms since pinealectomy and ocular enucleation do not affect behavioral rhythmicity of larvae (M.W.H.…”

Section: Introductionmentioning

confidence: 99%

Isolation and Phenogenetics of a Novel Circadian Rhythm Mutant in Zebrafish

DeBruyne

Hurd

Gutierrez

et al. 2004

Journal of Neurogenetics

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Widespread use of zebrafish (Danio rerio) in genetic analysis of embryonic development has led to rapid advances in the technology required to generate, map and clone mutated genes. To identify genes involved in the generation and regulation of vertebrate circadian rhythmicity, we screened for dominant mutations that affect the circadian periodicity of larval zebrafish locomotor behavior. In a screen of 6,500 genomes, we recovered 8 homozygous viable, semi-dominant mutants, and describe one of them here. The circadian period of the lager and lime (lag dg2 ) mutant is shortened by 0.7 h in heterozygotes, 403 and 1.3 h in homozygotes. This mutation also shortens the period of the melatonin production rhythm measured from cultured pineal glands, indicating that the mutant gene product affects circadian rhythmicity at the tissue level, as well as at the behavioral level. This mutation also alters the sensitivity of pineal circadian period to temperature, but does not affect phase shifting responses to light. Linkage mapping with microsatellite markers indicates that the lag mutation is on chromosome 7. A zebrafish homolog of period1 ðper1Þ is the only known clock gene homolog that maps near the lag locus. However, all sequence variants found in per1 cDNA from lag dg2 mutants are also present in wild type lines, and we were unable to detect any defect in per1 mRNA splicing, so this mutation may identify a novel clock gene.

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Development of a circadian melatonin rhythm in embryonic zebrafish

Cited by 128 publications

References 29 publications

Circadian time-keeping during early stages of development

Circadian time-keeping during early stages of development

Unraveling the mechanisms of the vertebrate circadian clock: zebrafish may light the way

Isolation and Phenogenetics of a Novel Circadian Rhythm Mutant in Zebrafish

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