Fig. 12. (A-E) Phenotypic analysis of embryos stained with phalloidin-rhodamine after injection of CsASH1 dsRNA. (A) Opisthosoma of an embryo injected with GFP dsRNA as a control. The embryo shows the normal number of invagination sites in the ventral neuroectoderm. The arrows point to the anterior-most lateral invagination sites. (B) Opisthosoma of an embryo injected with CsASH1 dsRNA. No invagination sites can be detected in the ventral neuroectoderm, with the exception of two lateral invagination sites (arrows). (C) Transverse optical section of an embryo injected with GFP dsRNA as a control; apical is towards the top. The invagination sites have decreased (arrow) and a second layer (bracket) of invaginated cells has formed. A developing neuropil is visible basally (arrowhead). (D,E) Transverse optical section of embryos injected with CsASH1 dsRNA; apical is towards the top. (D) The morphology of the neuroectodermal cells is disturbed, the cells have a rounded appearance (arrow). (E) In this segment, where only a reduced number of invagination sites has developed (arrows), the process of invagination seems to be blocked: no second cell layer is visible. o2 to o5, opisthosomal segments 1 to 5. Scale bars: 100 µm in A,B; 20 µm in C-E.