Figure 6

Correct ECM structure in the median fin fold and regenerating caudal fins is hampered in fndc3a^wue1/wue1 mutants. (A,B) F-actin in the median fin fold was visualized by phalloidin staining and localization of β-catenin by immunofluorescence (n = 6 for each group, 22–24 hpf). Cellular organization of ventral median fin fold cells and ECM matrix was symmetrically structured in control embryos and showed nuclear localization of active Wnt signals in apical cells (white arrowheads in B). fndc3a^wue1/wue1 mutants depicted cellular alterations and unstructured ECM assembly by showing irregular cell shapes (arrows in A), cavities within the fin fold (dashed lines in A) and speckled accumulation of β-catenin between cells (arrows in B). Nuclear localization of β-catenin in apical cells was maintained (arrowheads in B). (C,D) Fin regenerates of fndc3a^wue1/wue1 mutants stained for F-actin showed regenerate abnormalities (arrows in C), irregular regenerate borders (dashed lines in C) and cellular cavities (dashed lines in D; n = 4 for each group). (E,F) Fin regenerates of fndc3a^wue1/wue1 mutants stained for β-catenin depicted divergent ECM assembly (arrows in E), appearance of abnormal cells loosely attached to the regenerate (arrows in F) and cavities (dashed lines in F; n = 3 for each group). Images either show maximum intensity projections (30 to 40 single z-slices; z-distance: 1.5 µm) or a representative higher resolution single z slice.