A20 HET negatively modulates hepatic expression of cell cycle regulators before and after PH. Livers from WT and A20 heterozygous (HET) mice were recovered before (0) and 1, 2, 4 and 7 d after PH and evaluated for intrahepatic mRNA levels of (a) HGF, (b) TGFα and (c) p21, by qPCR. Graphs represent mean±S.E.M. mRNA levels normalized to levels of housekeeping 28 S rRNA, expressed relative to 0 WT mRNA levels (n=3-4 mice/group/time point). (d) Representative photomicrographs of nuclear p21 protein expression by immunohistochemistry (brown) before and 2 d after PH. Scale bars: 50 μm. Graph represents mean±S.E.M. of p21+ nuclei per high power field (HPF) (n=3 mice/group). (e) Representative western blots of p21 in WT and HET mouse livers before (0 d) and 2 d after PH and, (f) at different time points during the diurnal cycle, ranging from 8.00 am to 16.00 pm. (g) Representative western blots of p21, cyclin D1, cyclin E and phosphorylated retinoblastoma (P-Rb) in WT and HET mouse livers before (0 d) and 1, 2, 4 and 7 d after PH. GAPDH (e, f) and β-actin (g) immunoblots were used as loading control (n=2-3 mice/group/time point). *P<0.05, **P<0.01, ***P<0.001