AT skin primary fibroblasts (AG 04405 strain from the National Institute of Aging Cell Culture Repository) were cultured in Ham's F10 medium supplemented with 10% fetal bovine serum, 100 U/ml penicillin, and 100 ug/ml streptomycin. The population doubling (PD) of cells chosen for SAGE library construction was PD=21. The cells were ~80% confluent at the time of RNA isolation.
