Fig. 3.

The gonadal expression patterns of sdY, foxl2, nr5a1, and cyp19a1a (A and B) are in agreement with a repressive effect of SdY on the Foxl2 positive regulation of the aromatase promoter (C). (A) Gene expression profiles of sdY, nr5a1, foxl2b2, and cyp19a1a in male and female gonads from 33 to 125 dpf. All values represent the mean ± standard deviation of three biological replicates (in percentage of the highest measured value). The gray area highlights the period before the sexually dimorphic expression of trout foxl2 genes during gonadal differentiation. (B) Gonadal localization of foxl2b2 transcripts (NBT/BCIP signal in blue) in male and female gonads. foxl2b2 is expressed in somatic cells of both female and male gonads at 50 dpf and only in female gonads at later stages (60, 70, and 85 dpf). In males fed with estrogens (male E2) foxl2b2 is strongly up-regulated compared with control males quickly after (60 dpf) the application of the treatment (55 dpf). (Scale bar, 20 µm.) (C) Colocalization by double in situ hybridization of sdY (NBT/BCIP signal in blue) and foxl2b2 (HNPP/Fast Red signal in red fluorescence) in somatic cells of a rainbow trout male differentiating gonad at 50 dpf. Cell nuclei are shown in the dark-field panels stained with DAPI either with or without the HNPP fluorescent detection of foxl2b2. Germ cells are shown by an asterisk. (Scale bar, 20 µm.)