Correlation between total ^Aγ mRNA levels and transgene copy numbers in transgenic mouse lines (A) or MEL cell clones (B) carrying the μLCR(−201)^Aγ and μLCR(−382)^Aγ constructs. The excellent correlation observed in transgenic mice (r = .96, P < .0001) does not exist in MEL cell clones (r = .28, P = .18).