Fig. 2.

Characterization of cell invasion in zebrafish skin. a, b Labeling for cleaved Caspase-3. a The second cell within a club cell (white arrowhead) is unlabelled. b An example of a labeled skin cell (yellow arrowhead). c Label for β-catenin. In contrast to superficial epithelial cells, which have an enrichment of β-catenin at the periphery (white arrowhead), no enrichment is detectable in cells entering (red arrowhead) or within (yellow arrowhead) club cells. d Phalloidin label for f-actin. A strongly labeled cell (yellow arrowhead) is visible at the edge of a club cell. e, f Transverse sections through cell in d, showing the peripheral position of the cell relative to the club cell. g A fish expressing Lifeact-GFP in a motile cell that appears to be extending a protrusion into a club cell. h, i Transverse sections through the center of the club cell. The skin was labeled with 4-Di-2-ASP, which leaves most the club cell cytoplasm unlabelled. The invading cell is located near the base of the epithelium. j Label for LC3B is detected within the second cell (white arrowhead), but not surrounding it. k–m Three different time points of the skin of a fish expressing Lifeact-GFP in cell that appears to be mostly inside a club cell (arrowhead), but with protrusions extending outside. The insets show surface rendering of the green fluorescence across the z-stack. The cell changes shape over the period of imaging. n–p Label for ΔNp63 (magenta). No signal was detected in cells invading club cells (yellow and red arrowheads). q, r Two different focal planes of a fish with neutrophils expressing GFP under the control of the mpx promoter. Neutrophils are strongly fluorescent. The cytoplasm of a subset of club cells is weakly labeled; the cyan arrowhead indicates an unlabelled club cell. s Transverse section through a labeled club cell (yellow arrowhead) and neutrophil (white arrowhead). Scale bar = 10 µm