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Human Circadian Phenotyping and Diurnal Performance Testing in the Real World
Published on: April 7, 2020
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A Cryptochrome 2 mutation yields advanced sleep phase in humans.
Arisa Hirano1, Guangsen Shi1, Christopher R Jones2
1Department of Neurology, University of California, San Francisco, San Francisco, United States.
Elife
|August 17, 2016
Summary
A genetic mutation in the Cryptochrome 2 (CRY2) gene causes Familial Advanced Sleep Phase (FASP), leading to early sleep and wake times. This CRY2 mutation impacts circadian rhythm regulation and protein stability.
Area of Science:
- Genetics
- Chronobiology
- Molecular Biology
Background:
- Familial Advanced Sleep Phase (FASP) is an inherited disorder characterized by significantly early sleep and wake times.
- The genetic underpinnings of circadian rhythm disorders are increasingly being elucidated.
Purpose of the Study:
- To identify the genetic cause of FASP in a specific family.
- To investigate the molecular mechanism by which a CRY2 mutation affects circadian rhythms and sleep behavior.
Main Methods:
- Genetic sequencing to identify mutations in the CRY2 gene.
- Analysis of the identified CRY2 mutation's effect on protein conformation and stability.
- Phenotypic analysis of mutant CRY2 in a mouse model, including circadian period and light-induced phase shifts.
Main Results:
- A missense mutation (A260T) in the human CRY2 gene was identified and co-segregated with FASP in the affected family.
- The A260T mutation in CRY2 alters protein conformation, increasing its affinity for the E3 ubiquitin ligase FBXL3, leading to enhanced degradation.
- In mice, the CRY2 mutation resulted in a shortened circadian period and altered behavioral rhythms.
Conclusions:
- CRY2 stability, regulated by FBXL3, is crucial for the precise control of human sleep-wake timing.
- The identified CRY2 mutation provides a molecular link between genetic variations and advanced sleep phase disorder.
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