Genes feel the rhythm

We are all familiar with some effects of our circadian rhythm, but now researchers think that our daily cycles could affect more that just sleeping and eating.

The sleep/wake cycle is the most obvious effect of circadian rythm

New research from Colorado State University in the US suggests that the function of all genes in mammals is based on circadian rhythms. While scientists have long known that circadian rhythms regulate behaviour, the study shows that daily rhythm dominates all life functions and particularly metabolism.

Andrey Ptitsyn, a researcher in the Bioinformatics Centre said: “We discovered that all genes have a significant change in pattern of activity – or expression – throughout the day. Every pathway of gene expression is affected by circadian rhythms, and the timing of the rhythms from each group of genes that are synchronised is important.”

Ptitsyn discovered that gene activity oscillates in a “finely orchestrated” system and gene expression can be impacted by daylight and darkness – or a lack of both.

“It’s like a conductor walking away from an orchestra during a performance; each musician continues to play, gradually going out of key with the others,” said Ptitsyn.

He also discovered alternative short and long copies of some genes oscillating in the opposite phase. These genes are essential components of leptin signaling system, responsible for the sensation of satiety after eating.

In addition, genes can oscillate with different amplitude – the swing between the highest and the lowest point. Genes are expressed at very different levels, but most of them have the same relative change throughout the day. However, some genes show significant change in the amplitude in different organs or in response to a changing environment. Better understanding gene oscillation may provide researchers with clues for developing ways to treat people who overeat because of impaired leptin signaling.

“Anyone who diets, for example, knows you shouldn’t eat late, and now we are getting closer to understanding why exactly,” said Ptitsyn.

The study was published in PLoS Computational Biology.