Fig. 3.

Activity of the Ci-Tbx2/3 notochord CRM requires T-box binding sites. (A) Left: schematic representation of the 294 bp Ci-Tbx2/3 notochord CRM. Red boxes represent constructs with notochord activity; configurations exhibiting weak or lack of notochord activity are depicted by light-red and gray boxes, respectively. Dark purple rectangles depict T-box binding sites. Right: percentage of embryos exhibiting notochord staining when electroporated with the wild-type (WT) or T-box (T) mutant plasmids to the left of each bar. (B-I) Microphotographs showing X-Gal stained embryos expressing the constructs in A. Arrowheads are colored as follows: red, notochord; orange, muscle; purple, mesenchyme. m, mutant.