Light signaling to the zebrafish circadian clock by Cryptochrome 1a

• DOI: 10.1073/pnas.0704588104
• Publication Date: 2007-09-05T00:41:08Z
• Authors: T. Katherine Tamai; Lucy C. Young; David Whitmore
• Keywords: Entrainment (biomusicology); Phase response curve; Oscillating gene

Zebrafish tissues and cells have the unusual feature of not only containing a circadian clock, but also being directly light-responsive. Several zebrafish genes are induced by light, little is known about their role in clock resetting or mechanism which this might occur. Here we show that Cryptochrome 1a ( Cry1a ) plays key light entrainment clock. Intensity phase response curves reveal strong correlation between induction resetting. Overexpression studies acts as potent repressor function mimics effect constant to “stop” oscillator. Yeast two-hybrid analysis demonstrates protein interacts with specific regions core components, CLOCK BMAL, blocking ability fully dimerize transactivate downstream targets, providing likely for A comparison complete versus skeleton photoperiods reveals identical under these two conditions. However, amplitude oscillation much higher on photoperiod, levels light-induced . We believe machinery both continuous discrete fashion, leading entrainment, establishment high-amplitude rhythm even stopping long photoperiods.