DMEM selection medium

Histidine-free DMEM

100 units/ml penicillin

100 µg/ml streptomycin

2 mM glutamine

10% bovine calf serum

125, 250, or 500 µM l-histidinol (dilute in a 125 mM stock and store it at -20°C)

Histidine-free DMEM is available from Irvine Scientific (Santa Ana, California).

Add tetracycline to 0.5 μg/ml when appropriate (prepare a 10 mg/ml stock of tetracycline-HCl in 70% ethanol and store at -20°C). Selection medium that contains 0.5 μg/ml tetracycline-HCl may be stored protected from the light for approx. 1 month at 4°C.

Add puromycin to 3 μg/ml when appropriate.