PUBLICATION

Circadian time-keeping during early stages of development

Authors
Ziv, L., and Gothilf, Y.
ID
ZDB-PUB-060323-15
Date
2006
Source
Proceedings of the National Academy of Sciences of the United States of America   103(11): 4146-4151 (Journal)
Registered Authors
Gothilf, Yoav
Keywords
AANAT, light, period2, pineal, zebrafish
MeSH Terms
  • Animals
  • Arylalkylamine N-Acetyltransferase/genetics
  • Base Sequence
  • Circadian Rhythm/physiology*
  • Circadian Rhythm/radiation effects
  • Eye Proteins/antagonists & inhibitors
  • Eye Proteins/genetics
  • Gene Expression Regulation, Developmental/radiation effects
  • Larva/physiology
  • Larva/radiation effects
  • Light
  • Oligonucleotides, Antisense/genetics
  • Period Circadian Proteins
  • Pineal Gland/embryology
  • Pineal Gland/growth & development
  • Pineal Gland/physiology
  • Pineal Gland/radiation effects
  • RNA, Messenger/genetics
  • RNA, Messenger/metabolism
  • Zebrafish/embryology*
  • Zebrafish/genetics
  • Zebrafish/growth & development
  • Zebrafish/physiology
  • Zebrafish Proteins/antagonists & inhibitors
  • Zebrafish Proteins/genetics
PubMed
16537499 Full text @ Proc. Natl. Acad. Sci. USA
Abstract
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.
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