Abstract: Series 109, Lecture 6

The Harvey Lectures Series 109 (2013—2014)

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Lecture #6: Thursday, April 17, 2014 — Watch Video of Lecture

Biological Time Travels: A Circadian Rhythm Story

Michael Rosbash, PhD

Michael Rosbash, PhD

Professor of Biology
Peter Gruber Endowed Chair in Neuroscience
Investigator, Howard Hughes Medical Institute

Howard Hughes Medical Institute, Brandeis University

Waltham, Massachusetts

Dr Rosbash's Website

Beginning with genetic studies in Drosophila melanogaster, research over the past 30 years has shown that timekeeping in eukaryotes is based on a few transcription factors and a core negative feedback loop. The factors are temporally regulated at the level of activity and stability, which also has a major impact on timekeeping. Because the mechanisms and many key proteins are conserved between flies and humans, this clock must have existed and functioned similarly at least 550 million years ago. Circadian clocks are even more widespread; the elegant but very different circadian clock in cyanobacteria suggests that circadian clocks arose multiple times, which underscores their selective advantage. In this vein, it is estimated that perhaps 50% or more of the human transcriptome undergoes circadian oscillations at the mRNA level. Metabolism, physiology, hormone levels, behavior, the sleep-wake cycle—virtually every aspect of biology—is influenced by the circadian clock.