Expression of the ^Aγ* gene in cells containing a tandem array of the rHS32 ^Aγ*3′RE genome. RNA was extracted from 5 clones after passage for 6 months in culture. Samples were extracted from uninduced (−) cells and those induced (+) by culture for 3 days in 40 mmol/L hemin. The copy number of the unrearranged vector genome, as estimated from the Southern blot analysis of BsaBI-restricted DNA is given (#) on the left. The amounts of template RNA analyzed were 10 ng (lanes 1 and 5), 25 ng (lanes 2 and 6), 50 ng (lanes 3 and 7), and 125 ng (lanes 4 and 8) for clones 2 and 6 and 5, 10, 25, and 50 ng, respectively, for the others.