Unlike habitual keratinocytes, keratinocytes encircling the mammary rudiment are thin and elongated before invagination (E12.5) but not any more after invagination (E13.5). 3D reconstructed images of optical section stacks acquired with a laser scanning confocal microscope showing epithelium (EpCAM, green) and surface rendering of MECs, ring/neck cells, and epidermal cells at hillock (E12.5) and bulb (E13.5) stages. Scale bar, 40 µm. The video is related to Fig. 4. Frame rate is 30 frames/s.
