Fig. 7.

Activity of the utrophin A promoter is modulated by calcineurin and NFAT. (A) Schematic representation of a putative NFAT site in the utrophin A promoter. (B) EMSAs using protein extracts (lane “+ Ext”) incubated with

³²P-labeled double-stranded oligonucleotides corresponding to the NFAT motif (black arrow). Note the specific binding activity that is competed by a 200× molar excess of unlabeled probe (lane “+ C”). This binding can be supershifted by adding NFATc1 antibodies in the reaction mixture (white arrow; lane “+ Ab”). (C) C2C12 muscle cells transfected with plasmids containing the utrophin A promoter-LacZ reporter gene alone or with expression vectors containing CnA* or nNFATc1. (D) Mouse soleus muscles were transduced with plasmids containing the utrophin A promoter-reporter gene alone or with an expression vector containing CnA*. Note that, in these two sets of experiments, expression of active CnA* or nuclear NFATc1 increased (P < 0.05) the activity of the utrophin A promoter as measured by the relative abundance of LacZ transcripts. For the transfection experiments, n = 2 to 4 in duplicate. For the injection, n = 4 mice. Means ± SEM are shown.