Fig. 8. smp regulates Ol-pou5f1 expression. (A,B) Transverse sections, after WMISH, showing Ol-pou5f1 expression in early gastrula embryos after smpMO injection (8 mg/ml). Decreased expression was observed in deep cells, but not in the EVL of injected embryos (arrowhead). (C-F) Embryos injected at the 32-cell stage with EGFP RNA (100 µg/ml), either alone (C,E) or together with smpRNA (500 µg/ml, D,F). At mid-gastrulation (C,D, dorsal view), no apparent modifications can be observed (white dotted lines indicate the blastoderm margin). At the 2-somite stage (E,F, dorsal view), fluorescent cells are excluded from the embryo axis and are found near the anterior body axis. (G) Lateral view of a 2-somite stage control embryo showing Ol-pou5f1 expression in telencephalon (t) and tailbud (tb). (H,I) Ol-pou5f1 expression at the 2-somite stage after smpRNA injection into two-cell stage embryos. (H) Ectopic expression is visible in the telencephalon (t), ventral mhb and rhombencephalic domains (rb). (I) A more widespread expression is observed in strongly affected embryos. (J-O) Tranverse sections of WMISH embryos. (J-L) Control embryos. Ol-pou5f1 CNS expression is restricted to the dorsal telencephalon (arrowhead). (M-O) After injection of smpRNA, ectopic Ol-pou5f1 expression was observed in telencephalon (M, arrowhead), and in the ventral mhb (N, arrowhead) and rhombencephalon (O). Scale bars: 30 µm.