Fig. 5.

Mechanistic models of hepatocyte differentiation. (A) Schematic demonstrating progressive assembly of transcription complexes. Fetal/neonatal hepatoblasts have less complicated transcription factor complexes associated at enhancers of the same genetic locus compared to adult hepatocytes. (B) Schematic of differentiation-dependent enhancers. Example demonstrates that the enhancer at genetic locus X is occupied in fetal/neonatal hepatoblasts but not occupied in adult hepatocytes, and the enhancer at genetic locus Y is not occupied in fetal/neonatal hepatoblasts but is occupied in adult hepatocytes. (C) Schematic of a differentiation-independent enhancer. Example demonstrates that the enhancer at genetic locus Z is similarly occupied in both fetal/neonatal hepatoblasts and adult hepatocytes. (B and C) Representation of H3K4me1 average enrichment profiles of binding (red peaks) at differentiation-dependent and -independent enhancers in adult hepatocytes. Distinct binding patterns (bimodal and monomodal distribution) are present, depending on whether FoxA2 and Hnf4a are bound to enhancers.