Fig. 4. SDF1-coated beads capture migrating PGCs. (A) Trajectories of cells in a control slice. A BSA-coated bead was placed into the aorta of an E9.5 slice and the slice was filmed for eleven hours. Green outlines represent starting positions of cells and red outlines represent ending positions. A dotted outline indicates the position of the bead. (B-D) Trajectories of cells near beads coated with 10 (B), 25 (C) and 50 (D) µg/ml SDF1. (E) Summary of migration data from control and SDF1-coated bead experiments. Movies of three slices per treatment were analyzed, except for the 50 µg/ml treatment where movies of two slices were analyzed (see Movies at http://dev.biologists.org/supplemental/). Error bars show standard deviation. Scale bar: 55 µm (A-D).