1. Department of Microbiology and Molecular Genetics, Harvard Medical School and New England Primate Research Center, Southborough, Massachusetts
2. Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School and Laboratory of Molecular Medicine, Children's Hospital, Boston, Massachusetts
3. Department of Biology, Chemistry, Pharmacy, Freie Universität Berlin, Berlin, Germany
4. Department of Pediatrics, Harvard Medical School and Perlmutter Laboratory, Children's Hospital, Boston, Massachusetts