Mouse embryonic fibroblasts (Kyushu University)

After the head and the visceral tissues of the embryos were removed, the remaining tissues were minced and digested in trypsin (2.5 mg/ml) and EDTA (1 mM). The digested tissue was then dissociated by pipetting in mouse embryonic fibroblast medium (MEF) comprised of Dulbecco’s modified Eagle’s medium (DMEM) containing  fetal bovine serum (FBS, 10%),  L-glutamine (2mM) and penicillin/streptomycin, supplemented with DNase I (25 μg/ml). After a short incubation, the cells were collected by centrifugation, resuspended in MEF medium and plated in tissue-culture dishes.