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Fig. 4 Multiple abnormalities in MZnanog embryo architecture. (A-D) YSL (white arrows) forms normally in MZnanog. Lateral optical sections of wild type (WT; A,B) and MZnanog (C,D) stained for nuclei (SYTOX green) and cell membranes (rhodamine-phalloidin) at the 512-cell (A,C) and sphere (B,D) stages. (E-L′) Animal (E-L) and lateral (E′-L′) view of SYTOX Green-injected WT and MZnanog embryos in images captured from time-lapse recording (Movies 2 and 3). (E-H′) At oblong (E-F′) and sphere (G-H′) stages YSL nuclei of WT and MZnanog show no difference; two to three rows of YSL nuclei are visible in the periphery of blastoderm. (I-J′) Early dome stage (before the doming starts). (I,I′) In a WT embryo, YSL nuclei are compacted and aligned in one row in the periphery of blastoderm. (J,J′) In MZnanog, YSL nuclei do not compact; nuclei distribution is similar to sphere stage. (K-L′) 30% epiboly. In the WT (K,K′), but not in MZnanog (L,L′), some YSL nuclei move from periphery to the central region and doming occurs (compare yellow boxes that frame the YSL centers in K and L and yellow arrowheads that point to the YSL center in K′ and L′). (M,N) Yolk doming is visible in WT (M), but not MZnanog (N) at 4.7 hpf. Lateral view. YSL and YSL nuclei were labeled by tetramethylrhodamine-dextran and SYTOX Green co-injection. (O-P′) Actin was stained with rhodamine phalloidin in WT (O) and MZnanog (P) embryos, 8 hpf. O′ and P′ are magnifications of the boxed areas showing the EVL-YSL border. The punctate F-actin ring colocalized with vesicles is visible in the EVL-YSL border in the WT; no vesicles and two tiny rings are visible in MZnanog. (Q-S′) YCL microtubules were visualized by anti-tubulin staining at 6 hpf in WT (Q,Q′), MZnanog (R,R′) and MZspg (S,S′) embryos. Scale bars: 100 µm (A-D,E-L',M-P,Q-S); 20 µm (O′,P′); 200 µm (Q′,R′,S′).