Fig. 5. XlpouV depletion results in defective anterior and posterior neural patterning. (A) In situ hybridization for expression of Xlpou25 at neurula stages. Xlpou25 expression is visible in the developing neural tube at stages 13 and 14 and is then present in the midbrain hindbrain boundary (MHB) at stage 17. The arrowhead indicates the MHB. Xlpou91 showed an identical expression pattern (data not shown). (B) Embryos were injected with control MO or XlpouV MO as in Fig. 4C, and in situ hybridization carried out for Fgf8 expression at stage 16 and for En-2 and Krox20 expression at both stage 16 and stage 35. The insets show stage 16 embryos injected in one blastomere at the two-cell stage with MO and a lineage trace (orange). The arrowheads in the Fgf8 panel indicate the MHB. The arrowheads in the Krox20 panel indicate rhombomere 3 and 5 in the control MO-treated embryo and rhombomere 5 in the XlpouV MO-treated embryo. (C) In situ hybridization for expression of Xlpou25 at tailbud stages. The right panel is a transverse section through the posterior region of a stage 29 embryo. Xlpou91 showed an identical expression pattern (data not shown). (D) Depletion of XlpouV protein results in increased Xcad3 expression. Embryos were injected with control MO or XlpouV MO as in Fig. 4C, and in situ hybridization for Xcad3 expression performed on stage 28 embryos. (E) Whole-mount TUNEL staining. Embryos were injected with control MO or XlpouV MO as in Fig. 4C and TUNEL staining carried out at stage 11.5. Embryos are positioned with the blastopore to the bottom and both sides of the embryo are shown. The boxed areas are shown at higher magnification below the main images.