(A and B) Cross-section through the central cumulus of ubiquitously stained (via Pt-arm RNA in situ hybridization) control (A) and Pt-Ets4 RNAi (B) embryos. (C and D) control and Pt-Ets4 RNAi embryos stained for the cumulus marker Pt-fascin. Cells of the cumulus are dispersing in the Pt-Ets4 knockdown embryo (D). (E and F) Single color double stain of anterior Pt-otd expression (anterior ring) and nuclear localized pMAD in the cells overlaying the cumulus. pMAD signal is absent in Pt-Ets4 RNAi embryos (F). In situ hybridization for the ventral fate marker Pt-sog (G, G’, J and J’) or the segmental marker Pt-en (H, I, K and L) in control (G–I) and Pt-Ets4 knockdown embryos (J–L). The same embryos in fluorescence vs. bright field channel are shown in G and G’ as well as in J and J’. Nuclear stain (DAPI)/bright field overlay is shown in A-F, H, I, K and L. Flat mounted embryos in C-F. Lateral-ventral view (G, G’, J–K), lateral view (H), ventral view (I). Abbreviations: ch: cheliceral segment; L1-L4: walking leg bearing segments 1–4; O1: opisthosomal segment 1.