Note to users. If you're seeing this message, it means that your browser cannot find this page's style/presentation instructions -- or possibly that you are using a browser that does not support current Web standards. Find out more about why this message is appearing, and what you can do to make your experience of our site the best it can be.

Sci. STKE, 17 December 2002
Vol. 2002, Issue 163, p. tw472
[DOI: 10.1126/stke.2002.163.tw472]


Circadian Rhythms Waking Up on a Cloudy Morning

Several photoreceptors have been proposed to be critical for synchronizing the mammalian circadian clock, but the most promising is melanopsin, which is found in specialized retinal ganglion cells. To test melanopsin's functional relevance, Ruby et al. and Panda et al. examined mice in which the gene for melanopsin has been deleted and found that light was still able to entrain the clock but not as effectively. At low light levels, however, light could not entrain the clock in the mice without melanopsin. Thus, melanopsin is not the only photoreceptor but appears to be the one specialized for ensuring entrainment at low light levels.

N. F. Ruby, T. J. Brennan, X. Xie, V. Cao, P. Franken, H. C. Heller, B. F. O'Hara, Role of melanopsin in circadian responses to light. Science 298, 2211-2213 (2002). [Abstract] [Full Text]

S. Panda, T. K. Sato, A. M. Castrucci, M. D. Rollag, W. J. DeGrip, J. B. Hogenesch, I. Provencio, S. A. Kay, Melanopsin (Opn4) requirement for normal light-induced circadian phase shifting. Science 298, 2213-2216 (2002). [Abstract] [Full Text]

Citation: Waking Up on a Cloudy Morning. Sci. STKE 2002, tw472 (2002).

To Advertise     Find Products

Science Signaling. ISSN 1937-9145 (online), 1945-0877 (print). Pre-2008: Science's STKE. ISSN 1525-8882