Laboratory of Reproductive Biology, Department of Developmental Biology, National Institute for Basic Biology, Okazaki, 444-8585, Japan,
Fish Physiol Biochem. 2005 Apr;31(2-3):129-35. doi: 10.1007/s10695-006-0014-5.
Using semi-quantitative reverse transcriptase polymerase chain reaction we analyzed the ontogenic expression patterns of several nuclear receptors (estrogen receptors [ERalpha and beta], androgen receptors [ARalpha and beta], Ad4BP/SF-1 and Dax-1) and cytochrome P450 aromatases (brain and ovarian types) in whole brain and gonads of the Nile tilapia. ERalpha and beta transcripts were evident in both sexes with a high expression of ERalpha in females at 0 day after hatching (0 dah). ARalpha appeared early (0 dah) in males and while in females at 25 dah. Among the two types of cytochrome P450 aromatases, the expression of the brain type (bP450arom) but not the ovarian type (oP450arom) was evident from 0 to 90 dah in the whole brain of both males and females. Expression of Ad4BP/SF-1 in female brain began from 0 dah but in male brain at 5 dah. Expression of Dax-1 began at 0 dah and it was higher throughout in male brain than that of the female brain. In gonads, ERalpha and beta transcripts were evident in both sexes with slight variation. In females, both oP450arom and Ad4BP/SF-1 amplicons were evident at 15 dah. In males, although faint expressions of Ad4BP/SF-1 amplicons were evident at early duration of development, oP450arom did not appear until 90 dah. Conversely, expression of bP450arom was observed throughout in the developing testis with varied pattern while in developing ovary it was evident till 15 dah and reappeared only after 90 dah. Taken together, present results suggest that brain acts merely as a synchronizer in the sex differentiation process initiated by gonadal cues/factors in the Nile tilapia.
使用半定量逆转录聚合酶链反应，我们分析了几种核受体（雌激素受体[ERalpha 和 beta]、雄激素受体[ARalpha 和 beta]、Ad4BP/SF-1 和 Dax-1）和细胞色素 P450 芳香酶（脑型和卵巢型）在尼罗罗非鱼整个大脑和性腺中的个体发生表达模式。ERalpha 和 beta 转录本在两性中均有明显表达，ERalpha 在孵化后 0 天（0 dah）的雌性中表达水平较高。ARalpha 在雄性中出现较早（0 dah），而在雌性中则在 25 dah。在两种细胞色素 P450 芳香酶中，脑型（bP450arom）而不是卵巢型（oP450arom）的表达在 0 至 90 dah 时在两性大脑中均有明显表达。Ad4BP/SF-1 在雌性大脑中的表达从 0 dah 开始，但在雄性大脑中则从 5 dah 开始。Dax-1 的表达从 0 dah 开始，并且在雄性大脑中的表达始终高于雌性大脑。在性腺中，ERalpha 和 beta 转录本在两性中均有明显表达，略有差异。在雌性中，oP450arom 和 Ad4BP/SF-1 扩增子在 15 dah 时均有明显表达。在雄性中，尽管 Ad4BP/SF-1 扩增子的微弱表达在发育早期就有明显表现，但 oP450arom 直到 90 dah 才出现。相反，bP450arom 的表达在发育中的睾丸中一直存在，模式各异，而在发育中的卵巢中，它在 15 dah 时明显表达，仅在 90 dah 后再次出现。综上所述，目前的结果表明，大脑在尼罗罗非鱼性腺信号/因子启动的性别分化过程中仅充当同步器。
