Cryptochromes CLOCK expression

Somers DE, Devlin PF, Kay SA 1998 Phytochromes and cryptochromes in the entrainment of th Arabidopsis circadian clock. Science 282 1488-1490 Stanewsky R, Kaneko M, Emery P et al 1998 The cryb mutation identifies cryptochrome as a circadian photoreceptor in Drosophila. Cell 95 681-692 Wang ZY, Tobin EM 1998 Constitutive expression of the CIRCADIAN CLOCK ASSOCIATED 1 CCAl gene disrupts circadian rhythms and suppresses its own expression. Cell 93 1207-1217... 

T6th, R., Kevei, E., Hall, A., Millar, A.J., Nagy.E, and Kozma-Bogndr, L., Circadian clock-regulated expression of phytochrome and cryptochrome genes in Arabidopsis, Plant Physiol, 127,1607,2001. 

Surprisingly, cryptochrome was not found solely in the retina. In addition to low levels found in all tissues, Cryl was also expressed in the SCN, and Cryl mRNA oscillated with circadian rhythmicity, which indicated an additional role for cryptochrome in circadian clock function. Based on the mRNA expression pattern, we postulated a role for Cry2 in circadian photoreception in the retina as well as a hght-independent role for Cryl in the circadian clock mechanism in the SCN. 

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