Oscillation and feedback loops in regulatory networks

The concentration of many proteins inside cells oscillates with time.
These
oscillations can be sustained or damped, and are often on timescales of
minutes to hours. As the number of known examples of such oscillating
systems
increases, it is more and more relevant to try to understand whether there
are
common design principles in their regulatory circuit. I will discuss some
of
these examples and show that all of them are characterized by the presence
of
a negative feedback loop in the regulatory network. This result allows to
extract informations about the underlying network structure from the time
series of the concentrations.