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Accueil > EN > Research Areas > Complex Systems Dynamics > BIological Systems > Cellular stress response

Dynamic of Thermal Stress

par Webmestre - publié le

The dynamics of cellular heat shock response is addressed a joint approach coupling : single cell experiment] (video microscopy) and modeling genetic network.

The objective is to identify the essential ingredients of the dynamic cellular response, but also to probe the coupling of the cellular response to heat stress with other cellular functions (cell cycle, metabolism ...)

Thermal Stress in single cell :

The cellular response to heat stress involves the recruitment of a transcription factor (HSF1) on specific areas of the cellular DNA and forming of "stress granules".

Granules de stress lors d’une élévation de température à 43°C

By monitoring in real time the spatial distribution of a labeled protein within a living cell, the fluorescence video microscopy is the best tool for the study of the kinetics of thermal stress response, which characterized by the formation and disappearance of granules.

A digital video processing the extract granules kinetics of each cell and used to quantify the variability of the response. The quantitative data obtained are directly comparable to the results of mathematical models.

Activation et relaxation des granules de stress par une élévation de température à 41°C
Activation continue des granules de stress par une élévation de température à 43°C
Cinétique des deux granules de stress d’une cellule lors d’une élévation de température.

The increase in temperature is generated by a laser irradiation, enabling a fast temperature rise ( 1s) over a range of 37 ° C to 60 ° C. Laser irradiation also allow a great control in the temperature time profile. The cells are placed in an incubator under the microscope and can be observed for 3 days. For example, we can measure the influence of thermal stress on cell division, or the cycle phase at the time of stress.
The experimental device allows the joint application of thermal and oxidative stress, and therefore the study of entanglement of these two regulatory networks.


Modeling the heat shock response’s regulatory network

The purpose of the modeling approach developed here is not exhaustive mathematical transcription of known mechanisms of regulation of network, but the development of a minimal model (model ’coarse’) to probe the basic mechanisms of dynamic.

The purpose of modeling developed more than the reproduction of experimental data (the starting point) is in the questioning of the internal mechanisms of the network and the intricacies with other cellular functions such as cell cycle or metabolism.

PhD

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