Three American scientists win Nobel Prize in Physiology and Medicine 2017 for their work on the biological clock

The American scientists Jeffrey C Hall, Michael Rosbash and Michael W Young, who have won this year’s prize. Illustration:

The Nobel Prize in Physiology and Medicine 2017 was awarded to Jeffrey C. Hall, Michael Rosbash and Michael W. Young for their work on unraveling the molecular mechanisms controlling the circadian rhythm. The Nobel Assembly at Karolinska Institute in Stockholm honored the three scientists on October 2, 2017. The prize of nine million Swedish Kronor will be shared among them.

An internal biological clock. The leaves of the mimosa plant open towards the sun during day but close at dusk (upper part). Jean Jacques d’Ortous de Mairan placed the plant in constant darkness (lower part) and found that the leaves continue to follow their normal daily rhythm, even without any fluctuations in daily light. Illustration by The Nobel Committee for Physiology or Medicine. Illustrator: Mattias Karlén

The circadian clock is a system of proteins and genes that controls physiological activities such as sleep, appetite, brain function, blood pressure and body temperature. A gene called period regulates the day-night cycle. This gene codes for the protein PER which accumulates in the body during night. The PER accumulated overnight blocks its own production; its levels drop during the day and production starts again at night time. PER does not act alone, other associated proteins work together to synchronize the biological clock. Genes such as timeless and doubletime coding for proteins TIM and DBT respectively, are a part of this network.

A simplified illustration of the molecular components of the circadian clock. Illustration by The Nobel Committee for Physiology or Medicine. Illustrator: Mattias Karlén

The first studies were performed in Drosophila Melanogaster or fruit flies and published by the laureates in 1984. Hall and Rosbash collaborated at Brandeis University and isolated the period gene. Young at Rockefeller University uncoded the DNA sequence of the gene. Before their work, two other scientists, Seymour Benzer and Ronald Konopka (both now deceased) had found that fruit flies with a mutated period gene had a disrupted biological clock. A series of discoveries followed, uncovering the clock’s molecular systems, and this field is still an active area of research.

The circadian clock anticipates and adapts our physiology to the different phases of the day. Our biological clock helps to regulate sleep patterns, feeding behavior, hormone release, blood pressure, and body temperature. Illustration by The Nobel Committee for Physiology or Medicine. Illustrator: Mattias Karlén

When the internal clock falls out of rhythm such as after traveling across time zones, our well-being is affected and we experience jet lag. A chronic mismatch between the internal clock and earth’s day and night, for instance, due to shift jobs, has been associated with mood disorders, heart and neurodegenerative diseases, diabetes and cancer. Drug efficacy and its side effects are also affected by the time of the day.

The Nobel Assembly said, “Since the seminal discoveries by the three laureates, circadian biology has developed into a vast and highly dynamic research field, with implications for our health and wellbeing.”

On the occasion of this Nobel Prize announcement, President of The Physiological Society, Professor David Eisner, says,

“On behalf of physiologists in the UK and across the world, I congratulate Jeffrey Hall, Michael Rosbash and Michael Young for this award.

Their research has transformed our understanding of circadian biology. Having evolved on a planet with roughly a 24-hour cycle of day and night, we have evolved to anticipate when these changes happen. So much of our brain and body has the capability of 24-hour rhythms and this process needs to work well to ensure good health. Understanding how our daily biological clock works and how our body adapts to different phases of the day has huge implications for our health and wellbeing.

When someone’s biological clock is distributed they are more likely to have poor health, such as obesity or cardiovascular illness. This research will also help us develop better treatment for ill health, for example, if we can target particular components of the clock we can stop development of certain diseases.”

He also said this research demonstrates why an understanding of physiology is vital to understanding how our bodies respond to health and disease.

A detailed report on the laureates’ work can be found here.

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