Figure 4

Contributions of Bcd gradient behaviors to target expression slanting. (A) Profiles of distance differences between the dorsal and ventral sides of the wt embryos when measured as either projected distance (blue, left scale) or contour distance (red, right scale). The profiles are shown as a function of raw Bcd intensity on log scale. (B) Positions with equal Bcd intensity values are marked on the dorsal and the ventral sides of an average wt embryo frame. Lines that connect the locations on both sides of the embryo can be viewed as iso-concentration contour lines. The embryo shape (blue) is averaged from the 28 wt embryos analyzed in this study, with dorsal side up and anterior to the left. (C) Differences in target boundary positions between the dorsal and ventral sides. The expression boundary positions are measured as either projected distance from the anterior (blue, left scale) or contour distance (red, right scale), and the differences are plotted at their respective projected boundary positions (measured from the dorsal side and expressed as fractional embryo length x/L). From anterior to posterior, each pair of results represents data in the following order: Otd in 30 wt embryos, Hb in 24 1×-bcd embryos, Hb in 28 wt embryos, and Hb in 29 3×-bcd embryos. (D) Target expression boundary locations on both dorsal and ventral sides are marked on the average embryos frames. The average 1×-bcd embryo frame is shown in cyan, wt in blue, and 3×-bcd in green. Both Otd and Hb boundary positions are marked on the average wt embryo frame. Lines connecting the target boundary positions on two sides of the embryos are shown for visual comparison with those shown in Fig. 4B.