PUBLICATION

Functional Development of the Zebrafish Pineal Gland: Light-Induced Expression of Period2 is Required for Onset of the Circadian Clock

Authors
Ziv, L., Levkovitz, S., Toyama, R., Falcon, J., and Gothilf, Y.
ID
ZDB-PUB-050510-5
Date
2005
Source
Journal of neuroendocrinology   17(5): 314-320 (Journal)
Registered Authors
Falcon, Jack, Gothilf, Yoav, Toyama, Reiko
Keywords
none
MeSH Terms
  • Animals
  • Arylalkylamine N-Acetyltransferase/genetics
  • Arylalkylamine N-Acetyltransferase/metabolism*
  • Arylalkylamine N-Acetyltransferase/radiation effects
  • Biomarkers/metabolism
  • Circadian Rhythm/genetics
  • Circadian Rhythm/physiology*
  • Circadian Rhythm/radiation effects
  • Eye Proteins/genetics
  • Eye Proteins/metabolism*
  • Eye Proteins/radiation effects
  • Female
  • Fish Proteins/genetics
  • Fish Proteins/metabolism*
  • Fish Proteins/radiation effects
  • Gene Expression Regulation, Developmental/radiation effects*
  • Light
  • Male
  • Period Circadian Proteins
  • Pineal Gland/embryology
  • Pineal Gland/enzymology*
  • Pineal Gland/radiation effects
  • RNA, Messenger/analysis
  • Zebrafish/embryology
  • Zebrafish/metabolism*
  • Zebrafish Proteins
PubMed
15869567 Full text @ J. Neuroendocrinol.
Abstract
Abstract In zebrafish, the pineal gland is a photoreceptive organ that contains an intrinsic circadian oscillator and exhibits rhythmic arylalkylamine-N-acetyltransferase (zfaanat2) mRNA expression. In the present study, we investigated the role of light and of a clock gene, zperiod2 (zper2), in the development of this rhythm. Analysis of zfaanat2 mRNA expression in the pineal gland of 3-day-old zebrafish embryos after exposure to different photoperiodic regimes indicated that light is required for proper development of the circadian clock-controlled rhythmic expression of zfaanat2, and that a 1-h light pulse is sufficient to initiate this rhythm. Analysis of zper2 mRNA expression in zebrafish embryos exposed to different photoperiodic regimes indicated that zper2 expression is transiently up-regulated by light but is not regulated by the circadian oscillator. To establish the association between light-induced zper2 expression and light-induced clock-controlled zfaanat2 rhythm, zPer2 knock-down experiments were performed. The zfaanat2 mRNA rhythm, induced by a 1-h light pulse, was abolished in zPer2 knock-down embryos. These experiments indicated that light-induced zper2 expression is crucial for establishment of the clock-controlled zfaanat2 rhythm in the zebrafish pineal gland.
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