Fig. 7

Foxl2 is antagonized by dmrt1 in zebrafish gonads. A-B) Quantitative RT-PCR of adult ovaries and testes from adult fish. A) Comparison of adult wild-type ovaries to testes showed that foxl2 expression was 68 fold higher in ovaries compared to testis, therefore exhibited ovary-enriched expression. The expected upregulation of the granulosa cell marker, cyp19a1a, and diminished expression of the Sertoli cell marker sox9a were also observed in these samples. B) Comparison of adult dmrt1^E3ins mutant ovaries to wild-type ovaries (left) and mutant testes to wild-type testes (right) revealed a 4-fold increase in foxl2 expression in ovaries and a 41-fold increase in foxl2 in testes in dmrt1 mutants compared to wild-type. C-N) In situ hybridization on adult dmrt1^C41X +/− and −/− gonad cryosections. C-E are serial sections of the same testis. G-I are serial sections of the same gonad and J is an H&E stain of panel I. K-M are serial sections of the same gonad and N is an H&E stain of M. Headings designate the probe used. C-E) Dmrt1 heterozygous testes showed expected localization of dmrt1 (C) and amh (D) in germ cells and Sertoli cells, respectively, whereas foxl2 (E) was not detected. F) In wild-type ovaries, foxl2 transcript localized to the somatic cells of pre-vitellogenic and vitellogenic oocytes, a vitellogenic oocyte is shown. G-N) Two dmrt1 male mutant gonads are shown. G-J) A testis-like gonad with scant residual oocytes. K-N) An intersex gonad containing pre-vitellogenic oocytes. G, K) Dmrt1 was expressed in residual oocytes, but was not detected in all germ cells (arrow). H, L) Amh was not detected. I, M) Misexpression of foxl2 was found interstitially, in presumptive gonial cells but not in the follicles, as supported by H&E staining (J, N). Detection of dmrt1 transcript in homozygous mutants is attributed to the dmrt1^C41X allele producing mRNA. Scale bars=20 µm.