Photic Induction of mPer1 and mPer2 in Cry-Deficient Mice Lacking a Biological Clock

See allHide authors and affiliations

Science  24 Dec 1999:
Vol. 286, Issue 5449, pp. 2531-2534
DOI: 10.1126/science.286.5449.2531

You are currently viewing the abstract.

View Full Text

Log in to view the full text

Log in through your institution

Log in through your institution


Mice lacking mCry1 and mCry2 are behaviorally arrhythmic. As shown here, cyclic expression of the clock genesmPer1 and mPer2 (mammalian Periodgenes 1 and 2) in the suprachiasmatic nucleus and peripheral tissues is abolished and mPer1 and mPer2 mRNA levels are constitutively high. These findings indicate that the biological clock is eliminated in the absence of both mCRY1 and mCRY2 (mammalian cryptochromes 1 and 2) and support the idea that mammalian CRY proteins act in the negative limb of the circadian feedback loop. ThemCry double-mutant mice retain the ability to havemPer1 and mPer2 expression induced by a brief light stimulus known to phase-shift the biological clock in wild-type animals. Thus, mCRY1 and mCRY2 are dispensable for light-induced phase shifting of the biological clock.

  • * To whom correspondence should be addressed. E-mail: okamurah{at}

View Full Text

Stay Connected to Science