Cyp19a1a Promotes Ovarian Maturation through Regulating E2 Synthesis with Estrogen Receptor 2a in Pampus argenteus (Euphrasen, 1788)

Abstract

In the artificial breeding of <i>Pampus argenteus</i> (Euphrasen, 1788), female fish spawn before male release sperm, which indicates rapid ovarian development. In fish, aromatase is responsible for converting androgens into estrogens and estrogen plays a crucial role in ovarian development. In this study, we aimed to investigate the potential role of brain-type and ovarian-type aromatase to study the rapid ovarian development mechanism. The results showed that <i>cyp19a1a</i> was mainly expressed in the ovary and could be classified as the ovarian type, whereas <i>cyp19a1b</i> could be considered as the brain type for its expression was mainly in the brain. During ovarian development, the expression of <i>cyp19a1a</i> in the ovary significantly increased from stage IV to stage V and Cyp19a1a signals were present in the follicle cells, while <i>cyp19a1b</i> expression in the pituitary gland decreased from stage IV to stage V. To further investigate the function of Cyp19a1a, recombinant Cyp19a1a (rCyp19a1a) was produced and specific anti-Cyp19a1a antiserum was obtained. The expressions of <i>cyp19a1a</i>, <i>estrogen receptors 2 alpha</i> (<i>esr2a</i>), and <i>androgen receptor alpha</i> (<i>arα</i>) were significantly upregulated in the presence of rCyp19a1a. Meanwhile, <i>cyp19a1a</i> was expressed significantly after E2 treatment in both ovarian and testicular tissue culture. Taken together, we found two forms of aromatase in silver pomfret. The ovarian-type aromatase might play an important role in ovarian differentiation and maturation, and participate in E2 synthesis through co-regulation with <i>esr2a.</i> The brain-type aromatase <i>cyp19a1b</i> might be involved in the regulation of both brain and gonadal development.