Most of our physiological functions fluctuate throughout the day. They are coordinated by a central clock in the brain and by local oscillators, present in virtually every cell. Many molecular gearwheels of this internal clock have been described by Ueli Schibler, professor at the Faculty of Science of the University of Geneva (UNIGE), Switzerland. To study how the central clock synchronizes subordinate oscillators, the researcher's group used a variety of genetic and technological tools developed in collaboration with a team of UNIGE physicians. In this way, the scientists were able to directly observe the bioluminescence emitted by 'clock genes' in mice for several months. This biotechnology is applicable to numerous sectors of biomedical research, which attracted the attention of the editors from the journal "Genes & Development".
In mammals, there are many behaviors and biological functions that are regulated by internal clocks. Most of our cells have one, made from a family of 'clock genes', whose cyclic activity reaches a specific peak in 24 hours. These local oscillators are synchronized by a central 'pacemaker' in the brain which adjusts to light.
The firefly lights the way
The use of genetic engineering techniques enabled the study of molecular mechanisms that activate clock genes directly in cultured mammalian cells: 'We have coupled several of these genes to that of luciferase, the enzyme used by the female firefly for producing green light to attract males,' explained Ueli Schibler, member of the National Research Center Frontiers in Genetics. When a specific clock gene is activated in a cell that was transformed in this way, the light signal emitted can be measured using a highly sensitive bioluminescence detector. However, this device, which is capable of detecting signals on the order of a few photons, cannot be used for studying whole organisms. The contribution of Andr Liani's mechanical workshop, a
|Contact: Ueli Schibler|
Universit de Genve