FIG. 5.
Effects of altering orientation and spacing between the SOX and δEF3 sites in the DC5 enhancer. (A) The SOX binding site was mutated in DC5-M4 and reversed in orientation in DC5-SR. A 4-bp spacer was added between the SOX and δEF3 sites in DC5-I4a. Altered bases are shaded. The binding sites for SOX and δEF3 are shown at the top. (B) Octamerized DC5 fragments were placed upstream of the δ1-crystallin minimal promoter (−51 to +57) in both normal (N) and reverse (R) orientations relative to the direction of transcription. Activity of the mutated DC5 enhancers in panel A was assessed by transfecting luciferase reporter plasmids into patched cultures of lens cells and fibroblasts. Luciferase expression by reporter plasmids was normalized to that of the enhancerless plasmid pδ51LucII (−).