To investigate the regulatory role of the cyp19a1b aromatase gene in the sexual differentiation of largemouth bass (Micropterus salmoides, LMB), we obtained the full-length cDNA sequence of cyp19a1b using rapid amplification of cDNA ends technique. Tissue expression characteristics and feedback with 17-β-estradiol (E₂) were determined using quantitative real-time PCR (qRT-PCR), while gonad development was assessed through histological section observations. The cDNA sequence of LMB cyp19a1b was found to be1950 base pairs (bp) in length, including a 5′ untranslated region of 145 bp, a 3′ untranslated region of 278 bp, and an open reading frame encoding a protein consisting of 1527 bp that encoded 508 amino acids. The qRT-PCR results indicated that cyp19a1b abundantly expressed in the brain, followed by the gonads, and its expression in the ovaries was significantly higher than that observed in the testes (P < 0.05). After feeding fish with E₂ for 30 days, the expression of cyp19a1b in the pseudo-female gonads (XY-F) was significantly higher than that in males (XY-M) (P < 0.05), whereas expression did not differ significantly between XX-F and XY-F fish (P > 0.05). Although the expression of cyp19a1b in XY-F and XX-F fish was not significantly different after 60 days (P>0.05), both exhibited significantly higher levels than that of XY-M fish (P<0.05). Histological sections analysis showed the presence of oogonia in both XY-F and XX-F fish at 30 days, while spermatogonia were observed in XY-M fish. At 60 days, primary oocytes were abundantly observed in both XY-F and XX-F fish, while a few spermatogonia were visible in XY-M fish. At 90 days, the histological sections’ results showed that a large number of oocytes were visible in XY-F and XX-F fish. Additionally, the gonads of XY-M fish contained numerous spermatocytes. These results suggest that cyp19a1b plays a pivotal role in the development of ovaries and nervous system development in LMB.

为了探讨cyp19a1b芳香酶基因在大口黑鲈( Micropterus salmoides , LMB)性别分化中的调控作用，我们采用cDNA末端快速扩增技术获得了cyp19a1b全长cDNA序列。使用定量实时 PCR (qRT-PCR) 确定组织表达特征和 17-β-雌二醇 (E ₂ )反馈，同时通过组织学切片观察评估性腺发育。LMB cyp19a1b的cDNA 序列长度为 1950 bp，其中包括 145 bp 的 5' 非翻译区、278 bp 的 3' 非翻译区以及编码由 1527 bp 组成的蛋白质的开放阅读框。编码508个氨基酸。qRT-PCR 结果显示，c yp19a1b在大脑中大量表达，其次是性腺，且在卵巢中的表达量显着高于在睾丸中的表达量（P < 0.05）。饲喂 E ₂ 30 d 后，假雌性性腺（XY-F）中cyp19a1b的表达量显着高于雄性（XY-M）（P < 0.05），而假雌性性腺（XY-M）中 cyp19a1b 的表达量差异不显着（ P < 0.05）。 XX-F 和 XY-F 鱼 ( P > 0.05)。虽然 60 d 后 XY-F 和 XX-F 鱼中cyp19a1b的表达量差异不显着（P >0.05），但均显着高于 XY-M 鱼（P <0.05）。组织学切片分析显示，30天时，XY-F和XX-F鱼中均存在卵原细胞，而XY-M鱼中观察到精原细胞。60 天时，XY-F 和 XX-F 鱼中均观察到大量初级卵母细胞，而 XY-M 鱼中可见少量精原细胞。90天时，组织切片结果显示，XY-F和XX-F鱼中可见大量卵母细胞。此外，XY-M鱼的性腺含有大量精母细胞。这些结果表明，cyp19a1b在 LMB 卵巢发育和神经系统发育中发挥着关键作用。