Seminário de Biomatemática

9 de Dezembro 2008, 16h00

The noisy world of the cell: lessons from stochastic monallelic gene expression
Complexo Interdisciplinar, Sala B3-01

Jorge Carneiro (Instituto Gulbenkian de Ciencia, Oeiras, Portugal)

Abstract:

Our body is made of cells. Cells are tiny molecular machine assemblies that collectively ensure all the functions necessary for organism maintenance, survival, and reproduction. The cellular machinery is made of proteins which through their interactions and dynamics execute and regulate all cellular processes in a reliable way. The activity of each proteins depends on its abundance in the cell, which in turn depends on the level of expression of the gene that encodes it. As such, gene expression must by highly controlled, and the disruption of this control can compromise the viability of the whole organism. These considerations notwithstanding, gene expression involves a small number of molecules (some times only one molecule) and therefore it is, by nature, a stochastic process. The demonstration that gene expression shows significant random variation at the single cell level raises a paradox: our body is made of molecular machines which perform highly reliable functions and yet these machines operate under very noisy conditions. To gain insights into this puzzle, data on random monoallelic expression of cytokine and antibody genes were analysed and modelled as stochastic processes. The results indicate that the above paradox is only apparent, and that cells control the stochastic molecular noise '� la carte' to ensure their functions.

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