Neverland regulates embryonic moltings through the regulation of ecdysteroid synthesis in the water flea Daphnia magna, and may thus act as a target for chemical disruption of molting
Neverland regulates embryonic moltings through the regulation of ecdysteroid synthesis in the water flea Daphnia magna, and may thus act as a target for chemical disruption of molting
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DOI：
10.1002/jat.3306
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发表时间：
2016-11-01
影响因子：
3.3
通讯作者：
Iguchi, Taisen
中科院分区：
文献类型：
--
作者：
Sumiya, Eri;Ogino, Yukiko;Iguchi, Taisen
为了了解大型蚤胚胎蜕皮激素的生理作用，我们分析了蜕皮激素合成或降解的基因。在胚胎发生过程中，先天蜕皮激素的滴度出现两个高峰，之后发生胚胎蜕皮。neverland 1和shade的表达在第一个高峰前增加。击倒梦幻岛1或遮荫抑制胚胎蜕皮。Neverland 1-knockdown胚胎显示蜕皮激素滴度降低。原位杂交显示neverland 1在胚胎肠上皮细胞中表达，表明蜕皮激素合成的起始步骤。Copyright（c）2016 John Wiley & Sons，Ltd.摘要节肢动物的胚胎发育伴随着一系列的蜕皮。在胚胎发育过程中，枝节甲壳动物大型蚤在达到一龄新生儿之前蜕皮三次。以前的研究认为蜕皮激素可能调节D。大胚发生然而，先天蜕皮激素的波动与其功能之间的关系还没有直接的证据。最近，我们确定了参与蜕皮类固醇合成的基因，称为梦幻岛（梦幻岛1和梦幻岛2）和阴影以及参与蜕皮类固醇降解的基因（Cyp 18 a1）。了解蜕皮激素在D.我们对这些基因进行了表达和功能分析。在胚胎发生过程中检查先天蜕皮类固醇滴度显示产卵后41和61 h的蜕皮类固醇滴度的两个高峰。第一次和第二次胚胎蜕皮发生在每个蜕皮激素激增。neverland 1和shade的表达在蜕皮激素的第一个高峰之前开始增加。通过RNAi技术敲除neverland 1或shade，导致胚胎蜕皮和随后发育的缺陷。nvd 1基因敲除的胚胎中蜕皮激素滴度似乎降低。敲低Cyp 18 a1导致第一次蜕皮前的早期胚胎死亡。我们的原位杂交分析显示，nvd 1显着表达在胚胎肠上皮细胞表明网站的蜕皮激素生成的初始步骤，胆固醇转化为7-脱氢胆固醇，并可能为蜕皮激素的生产。综上所述，nvd 1在肠道上皮细胞中从头合成蜕皮类固醇刺激蜕皮，这是D.大胚发育这些发现将梦幻岛确定为化学物质的可能目标，包括各种已知会破坏蜕皮，发育和繁殖的杀虫剂。版权所有（c）2016约翰威利父子有限公司
To understand the physiological roles of ecdysteroids in Daphnia magna embryos, we analyzed the genes for ecdysteroid synthesis or degradation. The innate ecdysteroids titer during the embryogenesis showed two peaks after which embryonic moltings occur. Expression of neverland1 and shade increased before the first peak. Knocking-down neverland1 or shade inhibited embryonic moltings. Neverland1-knowckdown embryos showed lowered ecdysteroids titer. In situ hybridization revealed neverland1 was expressed in embryonic gut epithelium suggesting the site for an initial step of ecdysteroid synthesis. Copyright (c) 2016 John Wiley & Sons, Ltd.Abstract Embryo development in arthropods is accompanied by a series of moltings. A cladoceran crustacean Daphnia magna molts three times before reaching first instar neonate during embryogenesis. Previous studies argued ecdysteroids might regulate D. magna embryogenesis. However, no direct evidence between innate ecdysteroids fluctuation and functions has been forthcoming. Recently, we identified genes involved in ecdysteroid synthesis called, neverland (neverland1 and neverland 2) and shade and in the ecdysteroid degradation (Cyp18a1). To understand the physiological roles of ecdysteroids in D. magna embryos, we performed expression and functional analyzes of those genes. Examining innate ecdysteroids titer during embryogenesis showed two surges of ecdysteroids titer at 41 and 61 h after oviposition. The first and second embryonic moltings occurred at each ecdysteroid surge. Expression of neverland1 and shade began to increase before the first peak in ecdysteroid. Knockdown of neverland1 or shade by RNAi technique caused defects in embryonic moltings and subsequent development. The ecdysteroids titer seemingly decreased in nvd1-knowckdown embryos. Knockdown of Cyp18a1 resulted in early embryonic lethality before the first molting. Our in situ hybridization analysis revealed that nvd1 was prominently expressed in embryonic gut epithelium suggesting the site for an initial step of ecdysteroidgenesis, a conversion of cholesterol to 7-dehydrocholesterol and possibly for ecdysone production. Taken together, de novo ecdysteroid synthesis by nvd1 in the gut epithelial cells stimulates molting, which is indispensable for D. magna embryo development. These findings identify neverland as a possible target for chemicals, including various pesticides that are known to disrupt molting, development and reproduction. Copyright (c) 2016 John Wiley & Sons, Ltd.