Berlin 2008 – scientific programme

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BP: Fachverband Biologische Physik

BP 26: Posters II

BP 26.40: Poster

Thursday, February 28, 2008, 17:00–19:30, Poster A

Effect of fluctuations for the formation of spatial patterns of gene expression — •Thorsten Erdmann and Pieter Rein ten Wolde — FOM Institute for Atomic and Molecular Physics (AMOLF), Kruislaan 407, 1098 SJ Amsterdam, The Netherlands

During development of a drosophila embryo, the segmented structure of the adult body is determined by a sequentially refined pattern of gene expression domains along the anterior-posterior axis. The first zygotic genes to be expressed are the gap-genes. These are activated by the morphogen molecule bicoid and interact with each other by mutual repression or activation. The anterior-to-posterior gradient of morphogen concentration induces a stripe-pattern of domains in which one gene is predominantly expressed and the relative concentration of the corresponding protein is high. This pattern is very precise and robust against variations, e.g., in embryo length or morphogen concentration. Moreover, the domain boundaries are rather sharp although the small number of molecules makes fluctuations of protein concentration important and although small fluctuations in morphogen concentration close to the activation threshold strongly alter the expression level of a gene. We use a stochastic model for gene expression, protein diffusion and decay to investigate how domains of gene expression are positioned in space and how fluctuations affect the sharpness of their boundaries. Besides looking at a single target gene activated by the morphogen gradient we also investigate how a single morphogen gradient can control expression patterns of several, interacting genes.