Flying in different time zones often upsets our mood, sleep and behaviour. It was earlier thought to be just a matter of fatigue in the body. But recent studies have pin pointed the exact physiological and molecular steps of how it works. We have a biological clock or circadian rhythm which is upset by such situations like that of air travel. The Nobel Prize for Physiology or Medicine for 2017 has gone to Michael W. Young, Michael Rosbash and Jeffrey C. Hall who demonstrated the different genes involved in translating proteins accumulated in the cell nucleus responsible for circadian rhythms. Plants, animals and humans all show the physiological changes during day and night or 24-hour cycle.
The first step in this direction was the discovery of a gene which disrupted the circadian rhythm in fruit flies and was named as “period”. Jeffrey Hall and Michael Rosbash successfully isolated the “period” gene and found that the PER protein which it encodes in the cytoplasm gets accumulated in the nucleus during the night but later degraded during the day. The accumulation of PER protein in the nucleus itself blocks the activity of the “period” gene in a negative feedback mechanism thus promoting circadian rhythms. Unlocking the mystery of how PER protein reaches the nucleus from the cytoplasm was the discovery of another gene “timeless” by Michael Young, which encodes for TIM protein. When TIM protein binds with PER protein, the two together can enter the nucleus. Another gene “doubletime” was identified by Michael Young which encodes for DBT protein and controls the accumulation of PER protein thus resulting in oscillations in physiological parameters during the 24-hour period. Since a large number of genes in humans are affected by the circadian rhythms therefore these discoveries are expected to usher in a new era of research promoting human health and wellbeing.
Professor S. P. Singh, Ph.D.
Editor-in-Chief, Human Biology Review
Former Dean, Faculty of Life Sciences,
Punjabi University, Patiala, India