Engineers at the University of California, Santa Barbara's new Institute for Collaborative Biotechnologies and the Max Planck Institute (MPI) for Dynamics of Complex Technical Systems, in Magdeburg, Germany have analyzed the mechanism of genetic circuits by which the fruit fly regulates its circadian rhythm. The results are published in the August 30 Proceedings of the National Academies of Science. The mechanism controlling the biological clock generates a complicated dynamic behavior, oscillating back and forth and making it difficult to study, but also making it a good prototypical dynamic cellular system.
The circadian rhythm of the fruit fly is a regulatory system that takes its cues from the sun. When the sun rises it affects the light-sensitive neurons of the brain of the fruit fly, setting off reactions of proteins at a certain rate depending on the amount of light. The reactions set the clock. There are key proteins and two key feedback loops involved, making the system a hierarchical control scheme, a design tool often used in engineering.
The mechanism is called a negative feedback loop similar to that employed by an air conditioning thermostat system. It reacts when the temperature gets too cold by reducing the cooling.
The engineers are looking for the principles underlying the architecture of the fruit fly's system that enables it to be so robust, according to co-author Frank Doyle, a chemical engineer
who holds UCSB's Duncan and Suzanne Mellichamp Endowed Chair in Process Control. "We are very excited about
Contact: Gail Gallessich
University of California - Santa Barbara