Fig. 4

Tdrd12 deficiency results in masculinization and infertility in zebrafish. (A) Sex ratios of the progenies from the in-cross of tdrd12 heterozygous mutant fish (90 dpf). Among the progenies, all homozygous offspring developed into males. The total number of progenies for this analysis is 109. tdrd12^+/−: heterozygous progenies; tdrd12^+/+: wild-type progenies; tdrd12^−/−: homozygous progenies; (B–D) Appearance of the breeding tubercle (BT) clusters (red arrowheads) in the pectoral fin of all homozygous mutant fish (B) and wild-type males (C), but not in wild-type females (D), scale bar = 250 μm; (E–G) Anatomical views of the gonadal tissues of the Tdrd12-deficient fish and wild-type adults. Only atrophied testes were observed in Tdrd12-deficient adults (E), while normal testes (F) and ovary (G) could be observed in wild-types adults, scale bar = 500 μm; (H–J) Histological analyses of the gonadal tissues indicate no signs of germ cells in the atrophied testes of the Tdrd12-deficient adults (H), while normal spermatogenesis (I) and oogenesis (J) progresses in the wild-type adults, scale bar = 50 μm; (K) The fertilization rates of the mating between wild-type (tdrd12^+/+) males and Tdrd12-deficient fish with wild-type females at the 120-dpf stage were recorded. The average fertilization rates of the 10 fish from three separate experiments were measured. Each group consists of 10 pairs of fish. The data shown here represent the means ± standard error of the mean; and (L,M) Morphological observations of embryonic development at 11 hpf derived from the mating between wild-type females with Tdrd12-deficient adults (L) and wild-type males (M); eggs from wild-type females could be induced by Tdrd12-deficient fish, but no successful fertilization could be found, scale bar = 250 μm.