Fig. 4 pERK expression is elevated in RPIA-transgenic fish. (A) Representative images of pERK IHC results for the control (mC), and two RPIA-transgenic fish (Tg1 and Tg2) aged 7–11 months. The control fish displayed only a weak pERK signal. The 7- to 11-month-old Tg1 and Tg2 fish exhibited significant stronger staining. All the magnifications were ×400. Scale bar: 50 μm. (B) Statistical analysis of the IHC results for pERK expression of two independent Tg (fabp10a: RPIA)—Tg1 and Tg2 compared with control (mC) fish. Statistical analysis was performed by unpaired two-tailed t-tests. Asterisks (*) represent the level of significance. *P < 0.05 was considered statistically significant. **P < 0.01; ***P < 0.001. (C) Immunofluorescence staining of pERK in two independent RPIA-transgenic zebrafish (Tg1 and Tg2) compared with control (mC). The images showed that pERK (green) and DAPI (blue) immunofluorescent signals co-localized within nucleus in RPIA-transgenic zebrafish liver. All of the magnifications were ×400. Scale bar: 40 μm.