Figure 2

The effect of axis duplication and mesoderm induction modulation in medaka on PGC number. (A, B and C) Induction of a complete secondary embryonic axis was achieved by injection of β-catenin at the 8- and 16-cell stage. The injected embryos were fixed at stages 17 and 23 and their PGCs visualized by in situ hybridization using an olvas antisense RNA probe. A: a stage 23 control embryo injected with GFP-globin; B: a stage 23 embryo with a duplicated embryonic axis. In both stages analyzed, the average PGC number in embryos with a duplicated axis is similar to that of control embryos (C). (D to P) BMP-mediated mesoderm induction modulation was achieved by injection of either BMP2 (H to K) or dominant negative form of BMP2/4RI (DN(BMP2/4RI)) (L to O). To confirm mesoderm formation alteration, in situ hybridization was performed with either Goosecoid (Gsc) ventrolateral mesodermal marker (F, J and N) or HNF3-b axial mesodermal marker (G, K and O). One day post fertilization (dpf), the average PGC number in embryos with altered mesoderm is similar to that of control embryos (P). The number of embryos analyzed is provided within the corresponding bars.