Fig. 5. Lac accumulates at the SJs. Electron micrographs of the ectoderm of wild-type embryos at the end of embryogenesis, labelled with an anti-Lac antibody (A-D). The labelling is visible as gold particles (arrows). (A) Lac specific accumulation along the lateral membrane. (B,C) Lac in the SJs, visible as stretches of electron-dense membrane. (D) Tangentially sectioned SJs with Lac accumulation. (E) Shows a control sample treated equally, but not incubated with the primary antibody (see Materials and methods).