Nobel Prize in Medicine: What makes our internal clock tick

Three Americans were awarded the Nobel Prize in Medicine for discovering how our bodies adjust to the rhythm of day and night. It's all down to a few proteins. And yes, the proteins also give us that terrible jetlag.

All living creatures have a biological clock - no matter if it is a plant, a fruit fly or an astronomy professor.

It tells the body when it is night and when it is time to get up - or, if you're a plant, when it is time to do photosynthesis.

Jeffrey C. Hall, Michael Rosbash and Michael W. Young "figured out how it actually works," said Thomas Perlman of the Nobel Prize Committee for Physiology and Medicine when he announced the winners in Stockholm today.

For their discoveries of the molecular mechanism controlling the internal clock, Hall, Rosbash and Young were awarded the Nobel Prize for Physiology or Medicine today.

Science | 26.03.2013

Two of the laureates - Rosbash and Young - are still active reseachers in the US - at Brandeis University, Waltham, and Rockefeller University, New York, respectively. Jeffrey Hall is now professor emeritus at the University of Maine.

Unravelling a long-known phenomenon

"You are kidding me!" That's how Michael Rosbash is said to have responded when he heard that he had got the prize.

Illustration Nobelpreisträger Medizin 2017 DEU

Jeffrey Hall, Michael Rosbash and Michael Young were awarded the Nobel Prize in Medicine 2017

Other researchers were less surprised.

"It was obvious that it would go to these three if this research field was ever awarded with a Nobel Prize," Till Roenneberg, a chronobiologist at Ludwig-Maximilian University in Munich, told DW.

"They showed that the phenomenon of the internal clock is based on genes," he said.

Back in the 18th century, other researchers had discovered that plants have a circadian rhythm, closing their leaves at dusk and opening them again in the morning. Even if they stayed in darkness round the clock, they would still keep their 12-hour rhythm of opening and closing their leaves.

But nobody could explain at that time how the plants knew what time it was.

Up and down

In the 1970s, Seymour Benzer and his team found one gene that was involved in the circadian rhythm of fruit flies. Fittingly, they called it the "period gene."

Then in the 1980s, Hall, Rosbash and Young isolated the gene.

Hall and Rosbash, who worked together at Brandeis University even then, showed that it encoded for a protein which accumulated during the night and degraded during the day.

"The protein inhibits its own production," Roenneberg explains.

So the body knows that if the amount of the protein is high, it must be night, and vice versa.

It's an ever-repeating cycle which adjusts our bodies to the natural rotation of the Earth.

Erde mit Sonnenaufgang

In evolution, living creatures had to find a way to adjust to the Earth's rotation. That's why the internal clock developed.

This year's choice

So, why wasn't Seymour Benzer, discoverer of the period gene not awarded the Nobel prize? Well, Benzer died in 2007, and Nobel Prizes are not usually awarded posthumously.

Henrik Oster of the Institute for Neurobiology at Lübeck University jokingly told DW that he knows two other colleagues from the same field - still alive - who had hoped for a Nobel Prize but also missed out.

Oster says he was very pleased when he heard the Nobel Prize committee's announcement. "It is a great honour for our research field," he says.

The quite young and small research field of chronobiology, which examines periodic phenomena in living organisms, only took off after the new laureates' discovery in the 1980s.

Oster and Roenneberg know all three leaureates personally.

Oster describes Rosbash as "an outstanding personality, keen to debate and even quarrelsome," while Hall "stays more in the background."

Together they make a "good team."

Roenneberg adds that "all three of them are not only ingenious, but that their humour makes them very special."

Millions of internal clocks

"Nowadays we know that the internal clock is a very complex system," Roenneberg says. "There is not only one clock in the brain, but one in every cell of our body."

While the internal clock "is not essential for survival, it is extremely important to coordinate metabolic processes in the daily rhythm," Oster says.

Take the liver for example. It builds up glykogen from glucose during the day and breaks it down again at night, thus supplying the body with glucose.

Infografik Schlafrythmus innere Uhr Nobelpreisträger Medizin 2017 ENG

"If the building up and the breaking down were to take place at the same time, it wouldn't make sense at all," Oster says. "Both processes have to be separated in time."

When internal and external clocks do not harmonize, we feel sick, and, ultimately, get sick.

From jetlag to cancer

After flying from Los Angeles to Frankfurt, our internal clock runs slow. That's when we feel completely groggy, or as if we've been hit with a baseball bat.

While we normalize again after a few days, shift workers face a constant imbalance between external and internal clock - with negative consequences, including higher risk for diabetes, cancer and mental illnesses.

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Intelligent light

"The internal clock influences all processes that take place in our body," Roenneberg stresses.

While the internal clock is universal in all living creatures on Earth, it ticks differently in all of us, even from one human to another.

So, for instance, there are early birds and night owls. When researchers investigated skin cells of early and late risers, they found that the internal clock was ticking away a bit faster in the early risers' cells.

It is thanks to this year's Nobel laureates that we know that the internal clock is not only a lame excuse of some lazy people who can't get out of bed.

1902: It's a mosquito's fault

British researcher Ronald Ross found out that mosquitoes transmit the tropical disease malaria. He showed that the Anopheles mosquito carries one-celled parasites that cause malaria. Today, 200 million people a year still catch malaria, and about half a million of them die because of it. But thanks to Ross' findings, researchers were able to develop treatments to fight the disease.

1905: Bacteria cause TB

Robert Koch discovered the tuberculosis pathogen, the bacterium mycobacterium tuberculosis. Tuberculosis is still a globally widespread infectious disease. Treatment is possible but protracted, even though there are antibiotics for the illness today. There is also a vaccine which protects children, but not adults.

1912: Switching organs and stitching them up

French surgeon Alexis Carrel succeeded at transplanting blood vessels and entire organs. He developed a suture technique with which he could stitch torn blood vessels back together. He also discovered how to store organs outside the human body. Today, doctors transplant roughly 100,000 organs every year.

1924: Watching the heart beat

Dutch doctor Willem Einthoven developed the electro-cardiogram (EKG) to a point where it could be used in hospitals and doctor's offices. An EKG records the heart's electric activity. The data it provides helps doctors recognize an irregular heart rhythm and other heart diseases. It's a wide-spread method in modern medicine.

1930: Four types of blood

Austrian physician Karl Landsteiner discovered that mixing the blood of two different people often - but not always - led to clotting. He soon found the cause for that phenomenon: the different blood types A, B and O (which he called C). Later, his colleagues also discovered the blood type AB. Because of these findings, safe blood transfusions became possible.

1939, 1945 and 1952: Drugs to kill bacteria

Three Nobel Prizes went to the discoverers and developers of antibiotics, among them Alexander Fleming (1945), who discovered penicillin. Today, antibiotics are still some of the most commonly used drugs and often save lives. New kinds of antibiotics constantly need to be developed, however, as bacteria become resistant to the medicines.

1948: Attacking mosquitoes

The chemical compound DDT kills insects but hardly affects mammals, as Swiss chemist Paul Hermann Müller found out. Following that discovery, DDT became one of the most used insecticides worldwide. But then it turned out that DDT was damaging to the environment, especially to birds, and its use is now frowned upon. But it is still being used is places where mosquitoes are known to carry malaria.

1956: Straight to the heart

German physician Werner Forssmann received the Nobel Prize together with two colleagues for the development of cardiac catheterization. Forssmann conducted the procedure for the first time on himself. It calls for inserting a tube into an artery in the hand, bend of the elbow or the groin, and pushing it up to the heart.

1979 and 2003: Looking into the human body

When you wanted to see the inside of a human body, there used to be only one way: X-rays. But by now, doctors have superior methods. One of them is computed tomography (CT), which also uses x-rays, but takes detailed pictures of the body's "layers" as if it were cut into slices. The discovery was followed by that of magnetic resonance tomography (MRI), which works with harmless magnetic fields.

2008: Cancer caused by a virus

Thanks to Harald zur Hausen from the German Center for Cancer Research, we know that the human papillomavirus can cause cervical cancer. This knowledge helped the development of vaccines against the virus. Girls and women can now be vaccinated against the viral type of cervical cancer.

2010: Test-tube babies

Robert Edwards developed the in-vitro fertilization. The first baby that was created this way was born in England in 1978. Advancements improved the method's success-rate further. Globally, several million in-vitro babies have been born.