About the Authors
Institut de Génétique Humaine, CNRS UPR 1142, Montpellier, France
Centre d'Ingénierie Génétique Murine, Institut Pasteur, Paris, France
The authors have declared that no competing interests exist.
The author(s) have made the following declarations about their contributions: Conceived and designed the experiments: CG PB FB BdM. Performed the experiments: CG PB FB. Analyzed the data: CG PB FB BdM. Contributed reagents/materials/analysis tools: GCLF FL. Wrote the paper: CG FB BdM.