Dresden 2009 – scientific programme

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BP: Fachverband Biologische Physik

BP 18: Regulation and Signaling

BP 18.11: Talk

Thursday, March 26, 2009, 12:45–13:00, HÜL 186

Networks for cell division and their neutral mutants — •Gunnar Boldhaus and Konstantin Klemm — Bioinformatics Group, Department of Computer Science, University of Leipzig, Härtelstraße 16-18, D-04107 Leipzig, Germany

The functioning of a living cell is largely determined by the structure of its regulatory network, comprising complex, typically not pairwise interactions between regulatory genes. An important factor for the stability and evolvability of such regulatory systems is neutrality -- typically a large number of alternative structures exhibit the same dynamical behaviour. Here we study the regulatory networks for the cell cycles of the yeast species S. cerevisiae and S. pombe. A coarse-grained Boolean approach allows us to abstract from biochemical details such as precise binding constants and degradation rates.

We exhaustively enumerate all networks performing the same function as the yeast wildtype. For both species, the wildtype is close to optimal with respect to sparse wiring; almost all neutral mutants have more regulatory connections than the wildtype. Furthermore we analyse the reachability of the alternative networks from the wild type. This neutral space of regulatory networks is fragmented under point mutations which establish or delete single interactions.