Summary
This thesis establishes that the transcription factor Zfhx3 is critical for both adult circadian pacemaker function and developmental maturation of the SCN, the master circadian clock. Loss of Zfhx3 in SCN neurons leads to complete behavioural arrhythmia and inability to entrain to light-dark cycles, underscoring the importance of intact SCN neuropeptide signalling for light-responsive timekeeping relevant to therapeutic lighting strategies.
Key Findings
- Inducible deletion of Zfhx3 in adult mice caused acute shortening of circadian period and/or complete loss of rhythmicity in constant conditions.
- SCN-specific deletion using Six3-Cre resulted in complete behavioural arrhythmia in all lighting conditions and failure to entrain to a light-dark cycle in homozygous mutants.
- Histological analysis showed loss of expression of key circadian neuropeptides (e.g., VIP, AVP) in the SCN of Six3-Cre homozygous mutants, indicating failure of SCN maturation.
- Results confirm Zfhx3 is required for sustained SCN pacemaker function throughout the mouse lifespan, not only during development.
Categories
Sleep & Circadian Health: Demonstrates that Zfhx3 is essential for circadian pacemaker function, with loss of function causing period shortening, arrhythmicity, and failure to entrain to light-dark cycles.
The Science of Light: Provides mechanistic insight into SCN development and the molecular basis of circadian entrainment, relevant to understanding how light-dark cycles drive biological timekeeping.
Author(s)
A Wilcox
Publication Year
2019
Related Publications
Sleep & Circadian Health
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The Science of Light
- Phototransduction by retinal ganglion cells that set the circadian clock
- Color appearance models
- The mammalian circadian timing system: organization and coordination of central and peripheral clocks
- Diminished pupillary light reflex at high irradiances in melanopsin-knockout mice
- Melanopsin is required for non-image-forming photic responses in blind mice