Cloning of brain aromatase gene and expression of brain and ovarian aromatase genes during sexual differentiation in genetic male and female Nile tilapia Oreochromis niloticus
Cloning of brain aromatase gene and expression of brain and ovarian aromatase genes during sexual differentiation in genetic male and female Nile tilapia Oreochromis niloticus
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DOI：
10.1002/mrd.1042
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发表时间：
2001-08-01
影响因子：
2.5
通讯作者：
Penman, DJ
中科院分区：
文献类型：
--
作者：
Kwon, JY;McAndrew, BJ;Penman, DJ
从尼罗罗非鱼（Oreochromis niloticus）中鉴定出一个脑芳香酶基因。该基因的cDNA序列与以往报道的卵巢芳香化酶基因序列不同。在成年罗非鱼的组织中检测了脑和卵巢芳香酶基因的组织特异性表达。脑芳香化酶mRNA在脑、肾、眼、卵巢和睾丸中表达，而在肝脏和脾脏中不表达。卵巢芳香化酶mRNA在脑、脾、卵巢和睾丸中表达，而在眼、肾和肝中不表达。研究了罗非鱼全雄（XY）组和全雌（XX）组在受精后整个性别分化期的芳香酶基因表达差异。半定量RT-PCR分析显示，两种芳香化酶基因在受精后3 - 4天开始表达。在整个研究期间，脑芳香化酶mRNA水平逐渐升高，性别差异不大。这与卵巢芳香化酶mRNA表达的明显性别二态性形成对比。在雌性个体发育过程中，表达水平维持或逐渐升高，而在雄性个体发育过程中，表达水平在15 - 27 dpf之间显著下调。随后，卵巢芳香化酶mRNA的表达水平在两性中略有波动，女性的表达始终高于男性。这些发现清楚地表明，卵巢芳香化酶在该物种的性别分化中起着决定性作用，这是通过下调该基因在雄性中的表达来实现的。(C) 2001 Wiley-Liss, Inc。
A brain aromatase gene was identified from the Nile tilapia Oreochromis niloticus. The cDNA sequence of this gene differed from that of the ovarian aromatase gene previously reported from this species. Tissue specific expression for both brain and ovarian aromatase genes was examined in the tissues of adult tilapia. Brain aromatase mRNA was expressed in the brain, kidney, eye, ovary, and testis, but not in the liver and spleen. Ovarian aromatase mRNA was expressed in the brain, spleen, ovary, and testis but not in the eye, kidney, and liver. Differential aromatase gene expression between the sexes was investigated in all-male (XY) and all-female (XX) groups of tilapia fry from fertilisation throughout the sexual differentiation period. Semi-quantitative RT-PCR analysis revealed that the initiation of expression of both aromatase genes lay between 3 and 4 dpf (days post fertilisation) in both sexes. The level of brain aromatase mRNA gradually increased throughout the period studied with little difference between the sexes. This contrasted with marked sexual dimorphism of ovarian aromatase mRNA expression. In females, the expression level was maintained or increased gradually throughout ontogeny, while the level in males was dramatically down-regulated between 15 and 27 dpf. Subsequently, the level of ovarian aromatase mRNA expression fluctuated slightly in both sexes, with the expression in females always being higher than in males. These findings clearly suggest that ovarian aromatase plays a decisive role in sexual differentiation in this species and that this is achieved by downregulation of the expression of this gene in males. (C) 2001 Wiley-Liss, Inc.