Fig. 6. Dkk1 acts cell-autonomously in the somatic cells of the developing ovary. (A-E) Immunofluorescent staining of frozen sections with an anti-DKK1 antibody (red). Embryonic germ cells are detected by the anti-PECAM1 antibody (green). Note the DKK1 staining in the wild-type testis (A, arrowheads) and mutant gonads (C,D), but not in wild-type ovaries (B) or Dkk1-null testis (E). Magnification: 200x. (F-O) ISH was performed with Oct4 (F,G), Dkk1 (H-M) and Lrp6 (N,O) RNA probes on gonads from wild-type, Gata4^ki/ki, Fog2^-/- and W/W^v E12.5-13.5 mouse embryos as indicated. (G,I,K,M) Samples were derived from in vivo busulfan-treated embryos.