Figure 5.

HNF-4α is essential for normal hepatocyte differentiation. Steady-state mRNA levels from several genes normally expressed in differentiated hepatocytes was measured in livers isolated from HNF-4α^+/+ (lane 2), HNF-4α^+/− (lanes 5,6), and HNF-4α^−/− (lanes 3,4) ES-cell-derived embryos at day 12 of gestation by RT–PCR. All samples contained comparable amounts of cDNA, as HPRT primers amplified a similar level of product in all cases. HPRT primers did not amplify product in the absence of cDNA (lane 1). apoAI, apoAII, apoB, apoCIII, apoCII, and albumin, aldolase B, pAH, LFABP, TFN, RBP, and Epo mRNA levels were similar in HNF-4^+/+ and HNF-4^+/− livers. In HNF-4α^−/− livers the relative level of the same mRNAs was decreased dramatically and in some cases undetectable.