Institute of Molecular Systems Biology, ETH Zurich, Wolfgang-Pauli-Str, 16, 8093 Zurich, Switzerland. kuemmel@imsb.biol.ethz.ch|Institute of Molecular Systems Biology, ETH Zurich, Wolfgang-Pauli-Str, 16, 8093 Zurich, Switzerland. kuemmel@imsb.biol.ethz.ch|Institute of Molecular Systems Biology, ETH Zurich, Wolfgang-Pauli-Str, 16, 8093 Zurich, Switzerland. kuemmel@imsb.biol.ethz.ch