The Regulatory Factor ZFHX3 Modifies Circadian Function in SCN via an AT Motif-Driven Axis

Area of Science:

• Chronobiology
• Molecular Biology
• Genetics

Background:

• The suprachiasmatic nucleus (SCN) is the master circadian clock in mammals.
• Transcription factors play a crucial role in regulating circadian gene expression.
• Understanding the molecular mechanisms of circadian rhythmicity is vital for addressing sleep and metabolic disorders.

Purpose of the Study:

• To investigate the role of the Zfhx3 transcription factor in regulating circadian rhythms.
• To characterize the functional impact of the short circuit (Zfhx3(Sci)) mutation on ZFHX3 activity.
• To identify downstream targets of ZFHX3 in the SCN.

Main Methods:

• Identification and characterization of the Zfhx3(Sci) mutation in mice.
• In vitro assays to assess ZFHX3 DNA-binding and transcriptional activation.
• RNA sequencing to analyze gene expression changes in the SCN.
• Lentiviral transduction of SCN slices to study circadian regulation.

Main Results:

• The Zfhx3(Sci) mutation accelerates circadian locomotor rhythms in mice.
• Mutant ZFHX3 exhibits reduced ability to activate AT motifs in target genes, particularly neuropeptide genes.
• RNA sequencing revealed significant disturbances in neuropeptide gene expression critical for SCN signaling.
• Circadian regulation of AT motif activation by ZFHX3 showed decreased amplitude and robustness in mutant SCN slices.

Conclusions:

• The Zfhx3(Sci) mutation uncovers a novel circadian transcriptional axis involving ZFHX3.
• This axis is critical for determining the period and robustness of behavioral and molecular circadian rhythms.
• ZFHX3's regulation of neuropeptide gene expression is essential for SCN intercellular communication and rhythm stability.