Skin biopsy samples were obtained from four individuals in a previously characterized American family, pedigree H12 (Fig. 1a). C1 fibroblasts were from ATCC (CRL-2097). All studies followed institutional IRB, ISCRO and animal protocols approved by Johns Hopkins University School of Medicine. Informed consents were obtained from individuals from pedigree H. Mouse embryonic fibroblasts (MEFs) were derived from E13.5 CF-1 mouse embryos as previously described16. Fibroblasts were cultured in Dulbecco’s modified Eagle’s medium (DMEM, Mediatech) supplemented with 10% fetal bovine serum (FBS, HyClone) and 2 mM L-glutamine (Invitrogen).
