Fig. 2. Time-course analysis of MES degeneration in a live palate slice. MEE cells of 14.5 dpc palate shelves were labeled with CCFSE (bright signal) before contact. Three hours after contact, 200 µm transverse slices were produced. Selected individual slices were cultured, and micrographs of same slices were taken at 3, 6, 12 and 24 hours. At the end, cultured slices were processed for cell death detection (TUNEL positive, red). Note the accumulation of labeled cells in epithelial triangles at 3 and 6 hours of culture (blue arrows). At 6 and 12 hours of culture, the fragmented MES was obvious. At the end of culture (24 hours), the remaining labeled cells were detected as dying cells and none was clearly detected in the mesenchyme. These experiments were repeated more than three times at least in triplicate for each condition. Scale bar: 100 µm.