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Science 288 (5468): 943-944

Copyright © 2000 by the American Association for the Advancement of Science

CIRCADIAN RHYTHMS:
Two Feedback Loops Run Mammalian Clock

Marcia Barinaga

In the biological clock, the levels of one set of proteins crest while the others are low, and vice versa. Results described on page 1013 now show how the mammalian form of the biological clock keeps those opposed oscillations in sync. A research team reports that the key to this regulation seems to be a pair of proteins that enter the cell nucleus together but then apparently split their duties. One, called CRYPTOCHROME (CRY), turns off a set of genes, while the other, PERIOD2 (PER2), turns on a key gene.


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