Circadian Amplitude Regulation via FBXW7-Targeted REV-ERBα Degradation

Area of Science:

• Chronobiology
• Molecular Biology
• Metabolic Regulation

Background:

• Circadian rhythm defects affect sleep, metabolism, and cancer.
• Mechanisms regulating circadian clock amplitude remain incompletely understood.
• REV-ERBα is a core component of the circadian clock's inhibitory arm.

Purpose of the Study:

• To elucidate the regulatory mechanisms controlling the amplitude of circadian gene transcription.
• To identify novel factors involved in the post-translational modification and degradation of REV-ERBα.
• To explore the physiological consequences of disrupting the identified regulatory pathway.

Main Methods:

• Ubiquitination and degradation assays to study REV-ERBα stability.
• Western blotting and immunoprecipitation to detect protein interactions.
• Pharmacological inhibition and genetic disruption of FBXW7 and CDK1 in vivo.
• Analysis of circadian gene expression and metabolic parameters in liver-specific FBXW7 knockout mice.

Main Results:

• FBXW7 targets REV-ERBα for ubiquitination and degradation.
• CDK1-mediated phosphorylation of REV-ERBα is essential for FBXW7 recognition.
• FBXW7 relieves REV-ERBα-mediated repression, enhancing clock gene transcription amplitude.
• Hepatic FBXW7 disruption alters core clock gene expression and perturbs glucose and lipid metabolism.

Conclusions:

• The CDK1-FBXW7 pathway represents a novel mechanism for regulating circadian clock amplitude by controlling REV-ERBα stability.
• This pathway provides a link between cell cycle regulation and circadian transcription.
• Targeting CDK1 offers a potential strategy for manipulating circadian amplitude and metabolic homeostasis.