Quantification of Notch target gene her6 expression in embryos treated with GSI or fragments of Gleevec. Based on the segmented region of interest as highlighted in Fig. 7 A', the intensity of each ROI was quantified. The levels of her6 expression in DMSO treated embryos were normalized to 1, and relative levels of other embryos were calculated. Different regions of embryos were quantified, and the average of staining intensity of embryos treated with an individual compound was presented by a horizontal line in red, and the bar represents the standard error of means.