Fig. 8

Wnt/planar cell polarity (PCP) signaling in the epidermis regulates the directional scale growth. (A) Schematic drawings for the Wnt/PCP pathway. The intercellular domain of Fzd3a interacts with Dvl to regulate PCP of epithelial tissues. To generate a dominant-negative form of fzd3a, the intracellular domain of fzd3a was replaced with RFP (dnFzd3a). (B,C) In krt4p:gal4;UAS:dnFzd3a (krt4p:dnFzd3a) fish, the crescent-shaped domain of shha is not aligned along the body axis (arrows in C) compared with its wild-type sibling (B). (D–F) The krt4p:dnFzd3a fish exhibit misorientation of scales, extending in the wrong direction with regard to the body axis. If the fish has only one aberrant scale, that scale extends slightly in a ventral direction (arrows in E) compared with scales in the wild-type sibling (D). In contrast, when several aberrant scales are associated with each other, these scales rotate together at larger angles with regard to the body axis, occasionally creating a “whorl” of scales (F). Black ink was used to visualize the scale pattern, followed by Alizarin red staining (D′–F′, the area shown in (D–F)). (G,H) Orientations of the aberrant shha expression domains (G) and aberrant scales (H) in krt4p:dnFzd3a fish are quantified in wind rose diagrams. Scale bars, 100 µm (B,C), 500 µm (D–F,D′–F′).