The 2017 Nobel Prize in Physiology or Medicine has just been announced, and Jeffrey C. Hall, Michael Rosbash, and Michael W. Young are the winners. The scientists explained the workings of the circadian rhythm, a mechanism that is present in plants and animals. Seemingly and forever, the whole living world automatically adjusts to the changes in light and dark as the Earth spins around its axis, but the “whys” and “hows” of this process were only discovered in the 80s and 90s.
The figure shows the sequence of events during a 24h oscillation. When the period gene is active, period mRNA is made. The mRNA is transported to the cell’s cytoplasm and serves as template for the production of PER protein. The PER protein accumulates in the cell’s nucleus, where the period gene activity is blocked. This gives rise to the inhibitory feedback mechanism that underlies a circadian rhythm.
The three scientists led a research project that discovered, in fruit flies, a gene that is responsible for managing the body’s clock. This is done by the gene producing a protein called PER, the concentration of which builds up at night and which is depleted during daylight in flies synced to the Earth’s rotation. Moreover, the PER protein is part of a feedback loop that regulates the amount of PER that ends up being produced, which is the core mechanism that regulates the circadian rhythm. One of the important findings that explained how this all works is that another protein called TIM, controlled by a different gene, binds with the PER protein. While PER can’t enter the cell nucleus on its own to regulate the gene that produces it, when coupled with TIM it does indeed make it to its target. But, to understand how the time shift of a body clock happens, yet another gene, one that encodes for the DBT protein, had to be discovered. Turns out that this protein slows the build-up of the PER protein to compensate for changes in sunlight.
Since these discoveries, scientists have learned that a good deal of human genes are controlled by the body’s biological clock that, in turn, is controlled by circadian rhythms. This has led to a proliferation of related studies that continue to find correlations and causations between sunlight and our bodies. The findings have pointed to various diseases and conditions as being caused by a mismatch between the time of day and the activities the body participates in.
We congratulate the three laureates and thank them for the important work they have done. Countless people already benefit from their work and our understanding of our bodies has been deeply enriched.
Here’s a video of the announcement by the Nobel Assembly at Karolinska Institutet:
Original text announcement: The Nobel Prize in Physiology or Medicine 2017…
