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Monitoring Cell-autonomous Circadian Clock Rhythms of Gene Expression Using Luciferase Bioluminescence Reporters

Monitoring Cell-autonomous Circadian Clock Rhythms of Gene Expression Using Luciferase Bioluminescence Reporters

Published on: September 27, 2012

What makes the circadian clock tick: genes that keep time?

A Sehgal¹, A Ousley, Z Yang

¹Howard Hughes Medical Institute, Department of Neuroscience, University of Pennsylvania School of Medicine, Philadelphia 19104, USA.

Recent Progress in Hormone Research

|November 5, 1999

Summary

Circadian rhythms are driven by a molecular loop involving period (per) and timeless (tim) genes. Light differentially affects these genes in flies and mammals, highlighting conserved yet distinct clock mechanisms.

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Parallel Measurement of Circadian Clock Gene Expression and Hormone Secretion in Human Primary Cell Cultures

Parallel Measurement of Circadian Clock Gene Expression and Hormone Secretion in Human Primary Cell Cultures

Published on: November 11, 2016

Area of Science:

Chronobiology
Molecular Biology
Genetics

Background:

Circadian rhythms are fundamental biological processes.
The endogenous clock relies on molecular feedback loops.
Period (per) and timeless (tim) genes are key components.

Purpose of the Study:

To elucidate the molecular mechanisms generating circadian rhythms.
To understand the regulation of per and tim gene expression.
To compare light-induced responses in different species.

Main Methods:

Analysis of gene expression (RNA and protein) for per and tim.
Investigating post-transcriptional regulation.
Comparative studies across species (flies and mammals).

Main Results:

A conserved molecular feedback loop involving per and tim genes generates circadian rhythms.
PER protein cycling is largely post-transcriptionally regulated.
Light response mechanisms differ: TIM protein reduction in flies, per RNA induction in mammals.

Conclusions:

The circadian clock is a co-dependent system of per and tim genes.
Behavioral rhythms depend on the combined effect of both genes.
Dedicated photoreception pathways likely exist for circadian systems.