Ectopic expression of ecdysone oxidase impairs tissue degeneration in Bombyx mori
Ectopic expression of ecdysone oxidase impairs tissue degeneration in Bombyx mori
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DOI：
10.1098/rspb.2015.0513
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发表时间：
2015-06-22
影响因子：
4.7
通讯作者：
Tan, Anjiang
中科院分区：
文献类型：
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作者：
Li, Zhiqian;You, Lang;Tan, Anjiang
昆虫的变态包括一系列程序化的组织溶解和重塑过程，这些过程由两大类激素控制，即保幼激素和蜕皮激素。蜕皮类固醇（最活跃的蜕皮类固醇是20-羟基蜕皮激素，20 E）的精确脉冲受到生物合成和代谢的调节。在这项研究中，我们表明，蜕皮激素氧化酶（EO），20 E失活酶，主要表达在中肠在早期蛹阶段的鳞翅目模式昆虫，家蚕。使用转基因CRISPR/Cas9（成簇的规则间隔的短回文重复序列/RNA引导的Cas9核酸酶）系统消耗BmEO延长了末龄幼虫阶段的持续时间。利用Gal 4/UAS系统的BmEO的普遍转基因过表达在幼虫蛹转变期间诱导致死性。当BmEO在中间丝腺（MSG）中特异性过表达时，MSG在变态开始时的变性被阻断。透射电子显微镜和LysoTracker分析表明，MSG中的自噬途径被BmEO异位表达抑制。此外，RNA-seq分析显示，参与自噬细胞死亡和mTOR信号通路的基因受到BmEO过表达的影响。总之，BmEO功能研究报告提供了蜕皮激素调节变态过程中的组织退化的见解。
Metamorphosis in insects includes a series of programmed tissue histolysis and remolding processes that are controlled by two major classes of hormones, juvenile hormones and ecdysteroids. Precise pulses of ecdysteroids (the most active ecdysteroid is 20-hydroxyecdysone, 20E), are regulated by both biosynthesis and metabolism. In this study, we show that ecdysone oxidase (EO), a 20E inactivation enzyme, expresses predominantly in the midgut during the early pupal stage in the lepidopteran model insect, Bombyx mori. Depletion of BmEO using the transgenic CRISPR/Cas9 (clustered regularly interspaced short palindromic repeats/RNA-guided Cas9 nucleases) system extended the duration of the final instar larval stage. Ubiquitous transgenic overexpression of BmEO using the Gal4/UAS system induced lethality during the larval pupal transition. When BmEO was specifically over-expressed in the middle silk gland (MSG), degeneration of MSG at the onset of metamorphosis was blocked. Transmission electron microscope and LysoTracker analyses showed that the autophagy pathway inMSG is inhibited by BmEO ectopic expression. Furthermore, RNA-seq analysis revealed that the genes involved in autophagic cell death and the mTOR signal pathway are affected by overexpression of BmEO. Taken together, BmEO functional studies reported here provide insights into ecdysone regulation of tissue degeneration during metamorphosis.