Uptake assay at t=0. After exposure to extracellular anti-Dl antibody, Dl protein (red) is detected at similar levels apical to Cadherin (blue) in wild-type (GFP) and Dl∆β1-2 mutant tissue (GFP negative). (B') Cross-sectional view of B, Dl protein (red) is present apically relative to Cadherin (Blue) which marks adherens junctions. Middle and lower panels show the crosssection in grayscale of the apical marker Cadherin (Cad) and Delta (Dl), respectively. Uptake assay after 30 minutes, internalised anti-Dl (red) enters the endocytic route and in the cross sectional view (C') can similarly be detected as puncta along the cell axis in wild-type (GFP) and homozygous Dl∆β1-2 (GFP negative) tissue. Middle and lower panels show the crosssection in grayscale of the apical marker Cadherin (Cad) and Delta (Dl), respectively. 