About the Authors
Max-Planck-Institut für Entwicklungsbiologie, Tübingen, Germany
Max-Planck-Institut für Immunbiologie, Freiburg, Germany
European Molecular Biology Laboratory Heidelberg, Heidelberg, Germany
The authors have declared that no competing interests exist.
TD and NSF conceived and designed the experiments. TD, KL, DV, CS, and NSF performed the experiments. TD and NSF analyzed the data. TD, GN, CJN, and MH contributed reagents/materials/analysis tools. TD, DV, and NSF wrote the paper.