Ontogeny of circadian clock gene expression in the pineal and the suprachiasmatic nucleus of chick embryo.
Avian circadian rhythms are regulated by a multiple oscillatory system consisting of the pineal, the suprachiasmatic nucleus (SCN) and the eye. In the present study, ontogeny of circadian clock in the pineal and the SCN of chick embryo was examined using Per2 expression as a marker. A daily rhythmicity of Per2 expression was first detectable at embryonic day (ED) 18 in the pineal and at ED 16 in the SCN under light-dark (LD) cycles. The amplitude of the rhythmicity increased during the development. In contrast, little expression was observed during the development in constant darkness. These results suggest that although circadian clock matures by the end of the embryonic life in chicken, LD cycles are required for the expression of the Per2.
Okabayashi
Naritoshi
N
Division of Biomodeling, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan.
Yasuo
Shinobu
S
Watanabe
Miwa
M
Namikawa
Takao
T
Ebihara
Shizufumi
S
Yoshimura
Takashi
T
D000818:Animals; D002642:Chick Embryo; D002940:Circadian Rhythm / Q000235:genetics*; D003624:Darkness; D005136:Eye Proteins / Q000096:biosynthesis / Q000235:genetics; D005786:Gene Expression Regulation / Q000502:physiology*; D008550:Melatonin / Q000096:biosynthesis / Q000235:genetics; D010870:Pineal Gland / Q000196:embryology* / Q000502:physiology; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D013493:Suprachiasmatic Nucleus / Q000196:embryology* / Q000502:physiology
D005136:Eye Proteins; D012333:RNA, Messenger; D008550:Melatonin