FIGURE 7

FIGURE 7

Suppression of actin polymerization in mesenchymal cells induced the collapse of the actinotrichia distribution in vivo. The distribution pattern of the actinotrichia and the nuclei of mesenchymal cells in the TG larva (3 dpf) expressing the wild-type RhoA(A) or dominant negative form of RhoA(B) in mesenchymal cells. The actinotrichia and nuclei of mesenchymal cells were visualized by And1^full-GFP (green) and H2B-mRFP (magenta) respectively. (A′,A′′) The magnified images of the white box in (A). (A′) Nuclei of mesenchymal cells and (A′′) nuclei of mesenchymal cells and actinotrichia are shown. The transverse section image at the white dot line in (A′′) is shown at the lower panel. (B′,B′′) The magnified images of the white box in (B). (B′) Nuclei of mesenchymal cells and (B′′) nuclei of mesenchymal cells and actinotrichia are shown. The transverse section image at the white dot line in (B′′) is shown at the lower panel. Aberrant actinotrichia were distributed in a space between the two actinotrichia layers (white arrowhead). (C) The nucleus elongation ratio in mesenchymal cells expressing RhoA^DN is much lower than that in the control. The nucleus direction of mesenchymal cells in control larvae showed a radial distribution pattern, whereas, it was randomized in the larvae overexpressing RhoA^DN. The nucleus of mesenchymal cells in the ventral-mid area of median fins were measured. P-values: ***P < 0.0001. Scale bars: 50 μm in (A,B), 20 μm in (A′,A′′,B′,B′′).