Press Releases
Mar. 3, 2011

Molecular mechanism underlying the light-dependent resetting of the circadian clock and activation of locomotor activities

Presenters
  • Megumi Hatori (Department of Biophysics and Biochemistry, Graduate School of Science, The University of Tokyo)
  • Tsuyoshi Hirota (Department of Biophysics and Biochemistry, Graduate School of Science, The University of Tokyo)
  • Yoshitaka Fukada (Department of Biophysics and Biochemistry, Graduate School of Science, The University of Tokyo)

Abstract

Figure 1

Figure. A model for the role of SREBP in the light-dependent resetting of the circadian clock and activation of locomotor activities

The circadian clock is phase delayed or advanced by light when given at early or late night, respectively. Despite the importance of the time-of-day-dependent phase-responses to light, the underlying molecular mechanism is poorly understood. Here we found that SREBP transcription factor, which regulates a large group of cholesterol biosynthetic genes, activated transcription of E4bp4, a key regulator in the phase-delaying mechanism of the chicken pineal clock, in response to a light pulse at early night. Furthermore, we revealed that light-activated SREBP stimulated production and release of a neurosteroid 7α-hydroxypregnenolone in the pineal gland, resulting in the activation of locomotor activities of chicks. These results demonstrate a novel endocrine function of the pineal gland, which has been known to release sleep-related hormone melatonin.

Paper information

Megumi Hatori*, Tsuyoshi Hirota*, Michiko Iitsuka, Nobuhiro Kurabayashi, Shogo Haraguchi, Koichi Kokame, Ryuichiro Sato, Akira Nakai, Toshiyuki Miyata, Kazuyoshi Tsutsui, and Yoshitaka Fukada (* contributed equally)

“Light-dependent and circadian clock-regulated activation of sterol regulatory element-binding protein, X-box-binding protein 1, and heat shock factor pathways”

Proc. Natl. Acad. Sci. USA (Published online March 7, 2011)