Mutant __SP__ __NODE__ protein ( L391R with its ligand binding domain mutated ) in HepG2 cells increases trans activation of PPRE ( 5 ' TGAAACTAGGGTAAAGTTCA 3 ' from __SP__ __NODE__ gene in HepG2 cells that involves WY 14643 in culture medium and __SP__ __NODE__ protein in HepG2 cells .