Light-dependent expression of pinopsin gene in chicken pineal gland

Yoko Takanaka, Toshiyuki Okano, Masayuki Iigo, Yoshitaka Fukada

Research output: Contribution to journalArticle

37 Citations (Scopus)

Abstract

The phase of a circadian clock in the chicken pineal gland is reset by an environmental light signal, which is captured by the pineal photoreceptive molecule(s). Here we show that the mRNA level of pinopsin, a predominant photoreceptive molecule in the pineal gland, undergoes a diurnal fluctuation in chickens maintained on a light/dark cycle. The mRNA levels in the light were approximately six times higher than those in the dark. This fluctuation was not observed in constant darkness, where the mRNA levels remained low. Subsequent light exposure of chickens increased the amount of pinopsin mRNA regardless of the circadian time. Clearly, the expression of pinopsin gene is controlled by a light signal, independent of the circadian clock. In vitro experiments using cultured pineal glands isolated from the visual system also revealed the light-dependent increase in pinopsin mRNA level, indicating that the pineal photoreceptive molecule(s) is responsible for the induction. These results demonstrate the presence of a feedback loop through which the light signal captured by pinopsin stimulates the transcription of its own gene in the chicken pineal gland. In contrast, pinopsin protein remained at an almost constant level in chickens maintained under the same light/dark cycles. The protein level, however, decreased to ~50% of the light/dark level under constant darkness and subsequently increased upon exposure to light after the dark period. It is suggested that, under the light/dark cycles, the pinopsin protein level is kept constant by the light-dependent synthesis, which would compensate for a possible degradation of pinopsin in the daytime.

Original languageEnglish
Pages (from-to)908-913
Number of pages6
JournalJournal of Neurochemistry
Volume70
Issue number3
Publication statusPublished - 1998 Mar
Externally publishedYes

Fingerprint

Pineal Gland
Chickens
Genes
Gene Expression
Light
Photoperiod
Messenger RNA
Circadian Clocks
Darkness
Molecules
Clocks
Proteins
Transcription
Feedback
Degradation

Keywords

  • Chicken pineal gland
  • Circadian rhythm
  • Gene expression
  • Pinopsin

ASJC Scopus subject areas

  • Biochemistry
  • Cellular and Molecular Neuroscience

Cite this

Light-dependent expression of pinopsin gene in chicken pineal gland. / Takanaka, Yoko; Okano, Toshiyuki; Iigo, Masayuki; Fukada, Yoshitaka.

In: Journal of Neurochemistry, Vol. 70, No. 3, 03.1998, p. 908-913.

Research output: Contribution to journalArticle

Takanaka, Y, Okano, T, Iigo, M & Fukada, Y 1998, 'Light-dependent expression of pinopsin gene in chicken pineal gland', Journal of Neurochemistry, vol. 70, no. 3, pp. 908-913.
Takanaka, Yoko ; Okano, Toshiyuki ; Iigo, Masayuki ; Fukada, Yoshitaka. / Light-dependent expression of pinopsin gene in chicken pineal gland. In: Journal of Neurochemistry. 1998 ; Vol. 70, No. 3. pp. 908-913.
@article{48a61d31aca84b5e8678059225ce8696,
title = "Light-dependent expression of pinopsin gene in chicken pineal gland",
abstract = "The phase of a circadian clock in the chicken pineal gland is reset by an environmental light signal, which is captured by the pineal photoreceptive molecule(s). Here we show that the mRNA level of pinopsin, a predominant photoreceptive molecule in the pineal gland, undergoes a diurnal fluctuation in chickens maintained on a light/dark cycle. The mRNA levels in the light were approximately six times higher than those in the dark. This fluctuation was not observed in constant darkness, where the mRNA levels remained low. Subsequent light exposure of chickens increased the amount of pinopsin mRNA regardless of the circadian time. Clearly, the expression of pinopsin gene is controlled by a light signal, independent of the circadian clock. In vitro experiments using cultured pineal glands isolated from the visual system also revealed the light-dependent increase in pinopsin mRNA level, indicating that the pineal photoreceptive molecule(s) is responsible for the induction. These results demonstrate the presence of a feedback loop through which the light signal captured by pinopsin stimulates the transcription of its own gene in the chicken pineal gland. In contrast, pinopsin protein remained at an almost constant level in chickens maintained under the same light/dark cycles. The protein level, however, decreased to ~50{\%} of the light/dark level under constant darkness and subsequently increased upon exposure to light after the dark period. It is suggested that, under the light/dark cycles, the pinopsin protein level is kept constant by the light-dependent synthesis, which would compensate for a possible degradation of pinopsin in the daytime.",
keywords = "Chicken pineal gland, Circadian rhythm, Gene expression, Pinopsin",
author = "Yoko Takanaka and Toshiyuki Okano and Masayuki Iigo and Yoshitaka Fukada",
year = "1998",
month = "3",
language = "English",
volume = "70",
pages = "908--913",
journal = "Journal of Neurochemistry",
issn = "0022-3042",
publisher = "Wiley-Blackwell",
number = "3",

}

TY - JOUR

T1 - Light-dependent expression of pinopsin gene in chicken pineal gland

AU - Takanaka, Yoko

AU - Okano, Toshiyuki

AU - Iigo, Masayuki

AU - Fukada, Yoshitaka

PY - 1998/3

Y1 - 1998/3

N2 - The phase of a circadian clock in the chicken pineal gland is reset by an environmental light signal, which is captured by the pineal photoreceptive molecule(s). Here we show that the mRNA level of pinopsin, a predominant photoreceptive molecule in the pineal gland, undergoes a diurnal fluctuation in chickens maintained on a light/dark cycle. The mRNA levels in the light were approximately six times higher than those in the dark. This fluctuation was not observed in constant darkness, where the mRNA levels remained low. Subsequent light exposure of chickens increased the amount of pinopsin mRNA regardless of the circadian time. Clearly, the expression of pinopsin gene is controlled by a light signal, independent of the circadian clock. In vitro experiments using cultured pineal glands isolated from the visual system also revealed the light-dependent increase in pinopsin mRNA level, indicating that the pineal photoreceptive molecule(s) is responsible for the induction. These results demonstrate the presence of a feedback loop through which the light signal captured by pinopsin stimulates the transcription of its own gene in the chicken pineal gland. In contrast, pinopsin protein remained at an almost constant level in chickens maintained under the same light/dark cycles. The protein level, however, decreased to ~50% of the light/dark level under constant darkness and subsequently increased upon exposure to light after the dark period. It is suggested that, under the light/dark cycles, the pinopsin protein level is kept constant by the light-dependent synthesis, which would compensate for a possible degradation of pinopsin in the daytime.

AB - The phase of a circadian clock in the chicken pineal gland is reset by an environmental light signal, which is captured by the pineal photoreceptive molecule(s). Here we show that the mRNA level of pinopsin, a predominant photoreceptive molecule in the pineal gland, undergoes a diurnal fluctuation in chickens maintained on a light/dark cycle. The mRNA levels in the light were approximately six times higher than those in the dark. This fluctuation was not observed in constant darkness, where the mRNA levels remained low. Subsequent light exposure of chickens increased the amount of pinopsin mRNA regardless of the circadian time. Clearly, the expression of pinopsin gene is controlled by a light signal, independent of the circadian clock. In vitro experiments using cultured pineal glands isolated from the visual system also revealed the light-dependent increase in pinopsin mRNA level, indicating that the pineal photoreceptive molecule(s) is responsible for the induction. These results demonstrate the presence of a feedback loop through which the light signal captured by pinopsin stimulates the transcription of its own gene in the chicken pineal gland. In contrast, pinopsin protein remained at an almost constant level in chickens maintained under the same light/dark cycles. The protein level, however, decreased to ~50% of the light/dark level under constant darkness and subsequently increased upon exposure to light after the dark period. It is suggested that, under the light/dark cycles, the pinopsin protein level is kept constant by the light-dependent synthesis, which would compensate for a possible degradation of pinopsin in the daytime.

KW - Chicken pineal gland

KW - Circadian rhythm

KW - Gene expression

KW - Pinopsin

UR - http://www.scopus.com/inward/record.url?scp=0031940484&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0031940484&partnerID=8YFLogxK

M3 - Article

VL - 70

SP - 908

EP - 913

JO - Journal of Neurochemistry

JF - Journal of Neurochemistry

SN - 0022-3042

IS - 3

ER -