Research reveals fruit fly circadian clock mechanisms

The higher the temperature, the quicker the processes are. The sleep-wake cycle in organisms is regulated by the so-called melatonin. Scientists have a fascinating question about why the inner clock runs in an unchanging way. The phenomenon is called temperature compensation. Different mechanisms contribute to this.

An important piece in the puzzle has been found by a team of biologists led by Prof. Stanewsky from the University of Mnster in Germany. Their work has been published in a journal.

The team discovered a point abnormality in the fruit fly that causes it to change its temperature. It is located in the central clock genes. There is a normal sleep-wake rhythm of 24 hours at 18 degrees. The inner clock lasts 29 hours at 29 degrees. The period genes in the brain are affected by the length of periods.

Normally thePERIOD is phosphorylated in the course of a day or two. It is degraded after a certain point in time. At temperatures between 18 and 29 degrees Celsius, this process is the same as it is here. The researchers showed that the perI530A mutant decreases in temperature but increases inphosphorylation. At warmer temperatures, a stabilization of the "PERIOD"Protein can be achieved.

The nuclear export signal (NES), which occurs in the period genes of mammals and plays a role in transporting the PERIOD protein out of the cell nucleus, is affected by the team's study. There was no biological function of this export from the cell nucleus. The current study shows that the PERIODProtein is retained in the central clock neurons only at higher temperatures. As far as the fruit fly is concerned, we assume that the export of theprotein from the cell nucleus plays an important role.

The scientists used modern genetic methods to modify the fruit fly's perI530A genes. The animals were tested to see if their sleep-wake cycle differed depending on the temperature.

The clock genes were visualized using a variety of methods. The Mnster team collaborated with researchers in Canada to develop a new method called Locally Active Bioluminescence. The method of bioluminescence makes it possible to measure the expression of the clock genes in flies.

There is more information about the novel period mutation implicating nuclear export in temperature compensation of the flies. The article was published in the journalcub.

Journal information: Current Biology