Fig. 7.

Site-directed mutagenesis identifies sequences in the 47 bp enhancer that are necessary to confer activity-dependent regulation onto a heterologous promoter. Diagrammed are the wild-type and various mutant constructs used in these studies. Topdiagram shows putative regulatory regions of the δ −47 bp enhancer. Below this are shown the DNA sequences of the wild-type and various mutations. Mutations are shown in boldand lowercase type. δ-Enhancer MEK Luc constructs were co-injected with CMVCAT into innervated and denervated EDL muscles and assayed for Luc and CAT activity 1 week after injection. Results are shown with SD on the right side of the figure along with the fold differences. Values are represented as a percentage of wild-type expression in denervated muscle. Results were normalized to CMVCAT expression. Numbers in parentheses indicate number of animals injected. p-values (shown inbrackets) were calculated using a one-tailed ttest.