"This is the key protein in the eye that sends signals to the clock," says TSRI Cell Biology Professor Steve Kay, Ph.D., who led the study.
In an article appearing in the journal Science, Kay and his colleagues describe experiments in which they observe laboratory models that lack the Opn4 gene. They were able to show that without this gene, the models were not able to keep their circadian rhythms entrained to a 24-hour day. If a circadian rhythm were a grandfather clock, Opn4 (Melanopsin) would be the key that winds it every day. Previously, it was not known which genes were responsible.
This research should help in the development of strategies for correcting sleep disorders, many of which are related to circadian rhythms. Furthermore, understanding the protein that resets the body's clock should help in research aimed at countering the most common circadian problems--the jet-lag one feels after overseas flights or fatigue when working night shifts.
Circadian Rhythms are Entrained by Light
Humans, mice, and many other plants and animals possess internal clocks that keep track of time and coordinate biological processes to the rhythm of day and night. Scientists have provided evidence of the existence of internal clock mechanisms by placing organisms in chambers isolated from day/night cycles. In spite of this, their rhythms recur approximately every 24 hours.
This so-called circadian rhythm is used by plants, for example, to gear up their photosynthetic machinery and raise their leaves just before dawn. They also use their clocks to measure day length and in that way anticipate changes
Contact: Keith McKeown
Scripps Research Institute