Figure 2

Robo4 knockdown endothelial cells do not migrate to serum. A shows the migration assay for HUVECs transfected with 125–750 ng of siRNA in response to fetal bovine serum (FBS, black bar) or serum free (SF) conditions. B shows migration assay for HUVEC transfected with control lacZ siRNA (125 ng), robo4 siRNA (125 ng), robo4 siRNA (125 ng) plus zebrafish Robo4 (2 μg) (zfRobo4) constructs in response to fetal bovine serum (FBS) or serum free conditions (SF). Results were derived from three independent experiments (n = 3) with triplicate samples each time and the data is expressed as mean +/- SD. Two group comparisons were determined by Student two-sample t test assuming equal variances, and statistical significance was considered for p < 0.05. ** p < 9.83e-06 for control lacZ siRNA and R4 siRNA, and *p < 0.003 for R4 siRNA and R4 siRNA plus zfRobo4 samples. C shows the migration assay with control lacZ or robo1 siRNA transfected endothelial cells with the amounts indicated on the x-axis to fetal bovine serum (FBS) or serum free conditions (SF). This experiment was repeated twice with triplicate sample each time. D shows migration assay with control lacZ or robo1 or robo4 siRNA transfected endothelial cells to VEGF (100 ng/mL). This experiment was repeated three times with duplicate sample each time. Error bars in C and D represent SD across three independent experiments. In panels A-D, FBS was added to the bottom well.