Speaker
Mogens Hogh Jensen
(Niels Bohr Institute, University of Copenhagen)
Description
Oscillating genetic patterns have been observed in networks
related to the transcription factors NFkB, p53 and Hes1. We
have identified the central feed-back loops leading to
oscillations. By applying an external periodic signal, it is
possible to lock the internal oscillation to the external
signal. For the NF-kB systems in single cells we have
observed that the two signals lock when the ration between
the two frequencies is close to basic rational numbers. The
resulting response of the cell can be mapped out as Arnold
tongues. When the tongues start to overlap we may observe a
chaotic dynamics of the concentration in NF-kB. The group of
Savas Tay (ETH, Zurich) has in single cell dynamics of the
NF-kB system observed transitions from one tongue to the
other when they overlap. We investigate this effect by
Gillespie simulations and find interesting time correlation
for the transitions probabilities when switching from one
tongue to the other.
