1. Institute of Pathology, University Hospital Bonn 1 Department of Developmental Pathology , , 53127 Bonn , Germany
2. Institute for Cell Biology, University of Bonn 2 Department of Molecular Cell Biology , , 53121 Bonn , Germany
3. Utrecht University 3 Reproductive Biology Group, Division of Developmental Biology, Department of Biology, Faculty of Science , , 3584 CH Utrecht , The Netherlands
4. Institute of Genetics, University of Bonn 4 Cell Migration Unit , , 53115 Bonn , Germany