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Updated: Jun 12, 2026

Rapid Analysis of Circadian Phenotypes in Arabidopsis Protoplasts Transfected with a Luminescent Clock Reporter
Published on: September 17, 2016
cAMP-regulated dynamics of the mammalian circadian clock
1School of Informatics, Guangdong University of Foreign Studies, Guangzhou, China. wangjunweilj@yahoo.com.cn
Abstract:
Previous molecular description of the mammalian timekeeping mechanism was based mainly on transcriptional/translational feedback loops (TTFLs). However, a recent experimental report challenges such a molecular architecture, showing that the cAMP signaling is an indispensable component of the mammalian circadian clock. In this paper, we develop a reduced mathematical model that characterizes the mammalian circadian network. The model with 8-state differential equations incorporates both TTFLs and cAMP-mediated feedback loop. In agreement with experimental observations, our results show that: (1) the model simulates sustained circadian (23.4-h periodic) oscillations in constant darkness and entrained circadian dynamics by light-dark cycles; (2) circadian rhythmicity is lost without cAMP signaling; (3) the system is resilient to large fluctuations in transcriptional rates; (4) it successfully simulates the phenotypes of Per1(-/-)/Per2(-/-) double-mutant mice and Bmal1(-/-) mutant mice. Our study implies that to understand the circadian pacemaking in suprachiasmatic nucleus neurons, the TTFLs should not be isolated from intracellular cAMP-dependent signaling.
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