Doublesex- and Mab-3-Related Transcription Factor-1 Repression of Aromatase Transcription, a Possible Mechanism Favoring the Male Pathway in Tilapia
Doublesex- and Mab-3-Related Transcription Factor-1 Repression of Aromatase Transcription, a Possible Mechanism Favoring the Male Pathway in Tilapia
复制标题
双性和 Mab-3 相关转录因子 1 对芳香酶转录的抑制，有利于罗非鱼雄性途径的可能机制
DOI：
10.1210/en.2009-0999
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发表时间：
2010-03-01
期刊：
影响因子：
4.8
通讯作者：
Nagahama, Yoshitaka
中科院分区：
文献类型：
--
作者：
Wang, De-Shou;Zhou, Lin-Yan;Nagahama, Yoshitaka
Dmrt 1是一种与脊椎动物早期睾丸分化有关的重要转录因子，但其靶基因尚不清楚。在尼罗罗非鱼中，雌激素是卵巢分化的天然诱导剂。我们最近的研究表明，Forkhead-12上调转录的Cyp 19 a1 a基因（芳香化酶）在性腺中的女性特异性的方式。然而，在睾丸分化过程中下调Cyp 19 a1 a表达的上游因子仍不清楚。在本研究中，我们使用体外（启动子分析）和体内（转基因和原位杂交）的方法来研究Dmrt 1是否抑制Cyp 19 a1 a的转录活性。体外荧光素酶分析显示，Dmrt 1抑制HEK 293细胞中基础和Ad 4 BP/SF-1激活的Cyp 19 a1 a转录。Dmrt 1的各种缺失的荧光素酶测定也表明，Doublemex和Mab-3结构域是阻遏所必需的。体外翻译的Dmrt 1和罗非鱼精巢核提取物可以直接结合Cyp 19 a1 a启动子中的回文序列ACATATGT。在XX鱼中转基因过表达Dmrt 1导致芳香化酶基因表达降低，血清雌二醇-17 β水平降低，卵巢腔发育迟缓，不同程度的卵泡变性，甚至部分至完全性逆转。我们的研究结果表明，芳香化酶是Dmrt 1的目标之一。dmrt 1通过抑制罗非鱼和其他脊椎动物性腺中芳香化酶基因的转录和雌激素的产生来抑制雌性途径。（内分泌学151：1331-1340，2010）
Doublesex- and Mab-3-related transcription factor-1 (Dmrt1) is an important transcription factor implicated in early testicular differentiation in vertebrates, but its target genes are largely unknown. In the Nile tilapia, estrogen is the natural inducer of ovarian differentiation. Our recent studies have shown that Forkhead-l2 up-regulated transcription of the Cyp19a1a gene (aromatase) in the gonads in a female-specific manner. However, the upstream factor(s) down-regulating Cyp19a1a expression during testicular differentiation remains unclear. In the present study, we used in vitro (promoter analysis) and in vivo (transgenesis and in situ hybridization) approaches to examine whether Dmrt1 inhibits Cyp19a1a's transcriptional activity. The in vitro analysis using luciferase assays revealed that Dmrt1 repressed basal as well as Ad4BP/SF-1-activated Cyp19a1a transcription in HEK 293 cells. Luciferase assays with various deletions of Dmrt1 also showed that the Doublesex and Mab-3 domain is essential for the repression. In vitro-translated Dmrt1 and the nuclear extract from tilapia testis could directly bind to the palindrome sequence ACATATGT in the Cyp19a1a promoter, as determined by EMSAs. Transgenic overexpression of Dmrt1 in XX fish resulted in decreased aromatase gene expression, reduced serum estradiol-17 beta levels, retardation of the ovarian cavity's development, varying degrees of follicular degeneration, and even a partial to complete sex reversal. Our results indicate that aromatase is one of the targets of Dmrt1. Dmrt1 suppresses the female pathway by repressing aromatase gene transcription and estrogen production in the gonads of tilapia and possibly other vertebrates. (Endocrinology 151: 1331-1340, 2010)