Fig. 3. Skeletal muscle nuclear proteins bind selectively in the putative Slc2a4 CRE. Nuclear proteins extracted from rat soleus muscle and L6 muscle cells were subjected to electrophoretic mobility shift assay to determine the binding activity into the putative CRE site of the rat Slc2a4 promoter. Nuclear protein extracts (20Ág) were incubated with the radiolabeled wild type (WT) Slc2a4 CRE containing domain (probe); specific binding competitions were performed using 10-fold molar excess of unlabeled WT CRE, mutant 1 CRE (Mut1) and mutant 2 CRE (Mut 2). Representative image of the EMSA; the arrow indicates the specific protein/DNA band.