In a cell free system , the affinity of binding of a DNA fragment ( 219 190 ) containing a __NODE__ response element from __SP__ __NODE__ gene and heterodimer consisting of frog __NODE__ and of __NODE__ is greater than the affinity of binding of a DNA fragment ( 219 190 ) containing a __NODE__ response element from __SP__ __NODE__ gene and heterodimer consisting of frog __NODE__ and of __SP__ __NODE__ .