Afr2 regulation of Δ10 transgene expression during liver regeneration. Progeny of transgenic mice were mated with B6C3F1 mice and were assayed for the level of AFP and transgene expression after CCl4 injection. (A) Typical RNase protection assays for the two lines of transgenic mice tested. (H and L, high and low levels of endogenous AFP mRNA, respectively; *AFP MG, RNase protection assays carried out with 1 μg of input RNA.) (B) Relative levels of endogenous and transgene mRNA in individual Δ10A mice. Mice 1 and 2 were injected with mineral oil, and mice 3 through 21 were injected with CCl4. (C) Summary of the levels of AFP and transgene expression of all of the mice tested in both lines. Δ10A: AA, n = 10; AB, n = 9; Δ10B: AA, n = 11; AB n = 9. There were no statistically significant differences in the levels of transgene expression for any of the groups represented (P < 0.05).