Presentacion oral: The effects of temperature changes on the timing of cell division

FEDERICO VAZQUEZ

Berlin

Encuentro; DPG Spring Meeting; 2012

Accurate timing of early embryogenesis is crucial for the development of an organism, and is subject to sensitive dependence on fluctuations in temperature. We investigate how timing is affected by temperature using {\textit C. elegans} as a model organism, which benefits from rapid early cell divisions and an inability to maintain a constant body temperature, independent of ambient conditions. Experiments show that cell division rates have an Arrhenius dependence on temperature in an intermediate range, but they continuously deviate from this law outside this range, that is, for high and low temperatures. In order to explore this behavior we propose a simple model for cell division, in which the state of the cell performs a Brownian motion on a complex network with temperature-dependent hopping rates, and associate division rates to mean first-passage times. We obtain analytical expressions for simple topologies that fit the experimental data very well, showing that the fundamental mechanism behind the temperature dependence rates can be captured by a very low dimensional system. By comparing timings between different phases as a function of temperature, we are able to relate the lack of event coordination to the malfunction of the cell cycle at extreme temperatures. We also compare rates of {\textit C. elegans} and {\textit C. briggsae}, two closely related organisms known to differ in their optimal temperature range.