1. Department of Cell and Developmental Biology, Biocenter, University of Würzburg, Am Hubland, 97074 Würzburg, Germany
2. Institute of Molecular Biology (IMB), Ackermannweg 4, 55128 Mainz, Germany
3. Rudolf Virchow Center, University of Würzburg, Josef-Schneider-Strasse 2, 97080 Würzburg, Germany
4. Department of Biological and Medical Sciences, Oxford Brookes University, Oxford OX3 0BP, UK