The Clinical Research Unit 201 is a unique opportunity for young physician-scientists to establish the research expertise essential for achieving national and international visibility. Dr. Kramer-Zucker has undergone excellent training in zebrafish genetics in the laboratory of Prof. I. Drummond at the Harvard Medical School. He launched the first zebrafish facility in the Department of Medicine in Freiburg, and closely collaborates with the Department of Biology (Prof. Driever). He is author of several papers in developmental biology, and now senior author of a manuscript describing the tissue-specific functions of TRPP2/polycystin-2. His clinical training was completed in October 2007, enabling Dr. Kramer-Zucker to focus on his continuation project P3 as part of the CRU. Currently he is an attending physician in the Renal Division at the Department of Medicine. To ensure that he has sufficient time for research and supervision of project personnel, he will split a full-time attending position with Dr. Kühn (Project P6). Thus, each of them will have a considerable amount of protected time for their research projects.