News of the WeekCircadian Rhythms

Two Feedback Loops Run Mammalian Clock

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Science  12 May 2000:
Vol. 288, Issue 5468, pp. 943-944
DOI: 10.1126/science.288.5468.943a

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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.