1. Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
2. Sue and Bill Gross Stem Cell Research Program, Department of Biological Chemistry, Developmental and Cell Biology Department, Center for Molecular and Mitochondrial Medicine and Genetics, University of California Irvine, Irvine, California, USA
3. McKusick-Nathans Institute of Genetic Medicine, University of California, Los Angeles, California, USA
4. Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, California, USA