Figure 3: Hedgehog signalling is essential for gonadal development of GPCs.

(a) Expression plasmid for HipΔC22, a secreted Hedgehog antagonist, was electroporated with EGFP expression plasmid into GPCs (pink) at E2.0. (b,c) Boxed region indicated in a in control EGFP-electroporated embryos (E4.5). GATA4 mRNA (b) and SSEA1-positive primordial germ cells (PGCs) (c) were detected. (d) Illustrations of the development of gonads transfected with EGFP. (e–g) Magnified views of boxed regions in b–d. In control EGFP-electroporated embryos, GATA4-positive cells formed a swell (arrows in e and g) where SSEA1-positive PGCs localized (arrowheads in f). (h,i) Boxed region indicated in a in embryos (E4.5) transfected with HipΔC22 showing GATA4 mRNA expression (h) and localization of PGCs (i). (j) Schematic representation of the events in h and i. (k–m) Magnified views of boxed regions in h–j. In HipΔC22-overexpressing embryos, GATA4 was not expressed in the presumptive gonadal cells, the genital ridge was not formed (arrows in k and m), and the PGCs scattered (arrowheads in l and m). DA, dorsal aorta. Scale bars, 100 μm (b,c,h,i); 50 μm (e,f,k,l).