Abstract：
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.
摘要：
探讨cyp19a1b芳香化酶基因在大嘴鲈鱼性分化中的调控作用(Micropterussalmoides,LMB),我们使用cDNA末端快速扩增技术获得了cyp19a1b的全长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（E2）的反馈，而性腺发育是通过组织学观察来评估的。发现LMBcyp19a1b的cDNA序列长度为1950个碱基对（bp），包括145bp的5'非翻译区，278bp的3个非翻译区，和一个开放阅读框，编码由1527bp组成的蛋白质，编码508个氨基酸。qRT-PCR结果表明cyp19a1b在脑内大量表达,紧随其后的是性腺，其在卵巢中的表达明显高于在睾丸中的表达（P<0.05）。用E2喂鱼30天后，cyp19a1b在假雌性性腺(XY-F)中的表达明显高于雄性性腺(XY-M)(P<0.05),而XX-F和XY-F鱼的表达没有显着差异（P>0.05）。尽管XY-F和XX-F鱼中cyp19a1b的表达在60天后无显著差异(P>0.05),均显著高于XY-M鱼(P<0.05)。组织学切片分析显示，在30天的XY-F和XX-F鱼中均存在卵原，而在XY-M鱼中观察到精原细胞。在60天，在XY-F和XX-F鱼中大量观察到原代卵母细胞，而在XY-M鱼中可见一些精原细胞。90天,组织学切片结果表明，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的卵巢发育和神经系统发育中起着关键作用。
