Fig. 6. PAL-1 homeodomain binds to ced-3 promoter sequences. Electrophoretic mobility shift assay (EMSA) showing binding of labeled DNA derived from sites B and C (A and B, respectively) of the conserved C. elegans ced-3 promoter. Cold competitor DNA was added at concentrations of 10x (lanes 2, 7), 100x (lanes 3, 8), 200x (lanes 4, 9), 500x (lanes 5, 10) and 1000x (lanes 6, 11), as indicated by triangles above the autoradiogram. Lane 12 shows no binding of GST to labeled B or C DNA; lane 13 shows absent/weak binding of PAL-1 HD to labeled mutant oligonucleotide. Positions of shifted PAL-1 homeodomain-DNA complex and unbound DNA are indicated with arrows. (C) EMSA showing that wild-type DNA derived from site C can compete with labeled DNA derived from site B more effectively than mutant site C DNA. Cold competitor DNA was added at concentrations of 10x (lanes 2, 5), 100x (lanes 3, 6) and 1000x (lanes 4, 7). Details of the assay can be found in the Materials and methods section.