Photic induction of mPer1 and mPer2 in cry-deficient mice lacking a biological clock

Hitoshi Okamura, Shigeru Miyake, Yasuo Sumi, Shun Yamaguchi, Akira Yasui, Manja Muijtjens, Jan H.J. Hoeijmakers, Gijsbertus T.J. Van Der Horst

Research output: Contribution to journalArticlepeer-review

335 Citations (Scopus)


Mice lacking mCry1 and mCry2 are behaviorally arrhythmic. As shown here, cyclic expression of the clock genes mPer1 and mPer2 (mammalian Period genes 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. The mCry double-mutant mice retain the ability to have mPer1 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.

Original languageEnglish
Pages (from-to)2531-2534
Number of pages4
Issue number5449
Publication statusPublished - 1999 Dec 24
Externally publishedYes

ASJC Scopus subject areas

  • General


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