| To determine whether CHF 1 might affect the function of ARNT , we performed transfection studies . ^^^ Co transfection of CHF 1 inhibited ARNT / EPAS1 dependent transcription by 85 % , and this inhibition is dose dependent . ^^^ In electrophoretic mobility studies , CHF 1 inhibited the binding of the ARNT / EPAS1 heterodimer to its target site . ^^^ |