Expression of <i>fshr</i>, <i>cyp19a1a</i> and activins (<i>inhbaa</i>, <i>inhbab</i> and <i>inhbb</i>) in PG follicles from single (<i>gdf9-/-</i> and <i>inha-/-</i>) and double mutant (<i>gdf9-/-;inha-/-</i>).

(A-E) The PG follicles were isolated from the fish of different genotypes at 43 dpf, shortly before puberty onset or PG-PV transition occurs in the control fish (normally around 45 dpf). The expression of inhbaa was significantly reduced in gdf9-/- mutant; however, it was reversed by inha mutation in the double mutant together with fshr and cyp19a1a, but not inhbab and inhbb. Different letters indicate statistical significance (P < 0.05, n = 3 biological replicates). (F) Stimulation of Smad2/3 phosphorylation (p-Smad2/3) in the PV oocytes by activin in vitro. The PV follicles were isolated and treated with recombinant goldfish activin B (5 U/ml) for 2 h followed by immunofluorescent staining for p-Smad2/3.