Fig. 4
Phenotype analysis of the npr+/+ and npr-/- female zebrafish at 75 dpf.
(a) Gross morphology of the npr+/+ and npr-/- fish. (b,c) Body length (b) and body weight (c) of npr+/+ and npr-/- mutants (n = 6). (d) Ovary morphology of the npr+/+ and npr-/- fish. (e), Microscopic examination of follicles from npr+/+ and npr-/- mutants. Follicles were collected at 15:00 pm and matured oocytes (red arrows) could be observed in the npr-/- mutant. (f) The gonado somatic index (GSI) of npr+/+ and npr-/- fish (n = 6). (g) Spawning assay. No npr-/- fish succeeded in spawning (n = 30). (h) Ovary histology of the npr+/+ and npr-/- fish. The outer layer cells of the matured follicles (indicated by arrow) failed to breakdown in the npr-/- fish. (i) Oocyte maturation assay. FG stage follicles from npr+/+ and npr-/- fish were treated with IGF3 or 17α, 20β-DHP, and the percentages of follicles that underwent germinal vesicle breakdown (GVBD) were recorded. Each value represents the mean value ± SEM (n = 4) of three independent experiments (*P < 0.05; ***P < 0.001 vs npr+/+).