Fig. 5.

Neural crest migration is dependent on gonadal fate rather than genetic sex. (A and B) XX gonads from E17.5 Fgf9^lacZ/+ (A) and Fgf9^lacZ/lacZ (B) embryos. (C and D) XY gonads from E17.5 Fgf9^lacZ/+ (C) or Fgf9^lacZ/lacZ (D) embryos. All samples were stained for the pan-neuronal marker TUJ1 (red), and counterstained with Hoechst nuclear dye (grayscale). XX samples and Fgf9^lacZ/lacZ XY samples were stained for the granulosa cell marker FOXL2 to label the ovary (cyan, A, B, and D). Fgf9^lacZ/+ XY samples were stained with the Sertoli cell marker AMH to label the testis (cyan, C). (Scale bars, 100 µm.) (E) RT-qPCR analysis of relative mRNA expression of common neural crest attractive (Semaphorin 3c, Cxcl12, Neuregulin 1) or repulsive (Semaphorins 3a, 3f, 4a, 6a, 6c, and Slit3) cues in gonads from E14.5 (dashed bars) and E16.5 (solid bars) XY (black bars) or XX (white bars) embryos. Data were normalized to Gapdh expression. Values presented are the mean ± SEM of n = 4 pairs of gonads converted to fold changes compared with E14.5 XY samples for each gene. *P < 0.05 by two-tailed standard t test. (F) RT-qPCR analysis of relative mRNA expression of Semaphorins 3a, 6c, and Slit3 in gonads from E16.5 XY Fgf9^lacZ/+ (black bars), XY Fgf9^lacZ/lacZ (dashed bars), or XX Fgf9^lacZ/+ (white bars) embryos. Data were normalized to Gapdh expression. Values presented are the mean ± SEM of n = 3 pairs of gonads converted to fold changes compared with XY Fgf9^lacZ/+ samples for each gene. *P < 0.05; **P < 0.01 by two-tailed standard t test.