Speaker
Prof.
Mogens Hogh Jensen
(NBI)
Description
Oscillating genetic patterns have been observed in networks
related to the transcription factors NFkB, p53 and Hes1 [1].
We identify the central feed-back loops and found
oscillations when time delays due to saturated degradation
are present. By applying an external periodic signal, it is
sometimes 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 [2]. The resulting response of the cell can be
mapped out as Arnold tongues. When the tongues start to
overlap we observe a chaotic dynamics of the concentration
in NF-kB [2]. Oscillations in some genetic systems can be
triggered by noise, i.e. a linearly stable system might
oscillate due to a noise induced instability. By applying an
external oscillating signal to such systems we predict that
it is possible to distinguish a noise induced linear system
from a system which oscillates via a limit cycle. In the
first case Arnold tongues will not appear, while in the
second subharmonic mode-locking and Arnold tongues are
likely [3].
[1] B. Mengel, A. Hunziker, L. Pedersen, A. Trusina, M.H. Jensen and S. Krishna, "Modeling oscillatory control in NF-kB, p53 and Wnt signaling", Current Opinion in Genetics and Development 20, 656-664 (2010).
[2] M.H. Jensen and S. Krishna, "Inducing phase-locking and chaos in cellular oscillators by modulating the driving stimuli", FEBS Letters 586, 1664-1668 (2012).
[3] N. Mitarai, U. Alon and M.H. Jensen, "Entrainment of linear and non-linear systems under noise", Chaos, to appear (2013).
[1] B. Mengel, A. Hunziker, L. Pedersen, A. Trusina, M.H. Jensen and S. Krishna, "Modeling oscillatory control in NF-kB, p53 and Wnt signaling", Current Opinion in Genetics and Development 20, 656-664 (2010).
[2] M.H. Jensen and S. Krishna, "Inducing phase-locking and chaos in cellular oscillators by modulating the driving stimuli", FEBS Letters 586, 1664-1668 (2012).
[3] N. Mitarai, U. Alon and M.H. Jensen, "Entrainment of linear and non-linear systems under noise", Chaos, to appear (2013).
Primary author
Prof.
Mogens Hogh Jensen
(NBI)