Jiangsu Key Laboratory of Sericutural Biology and Biotechnology, School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, Jiangsu 212018, China.
Jiangsu Key Laboratory of Sericutural Biology and Biotechnology, School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, Jiangsu 212018, China; Key Laboratory of Silkworm and Mulberry Genetic Improvement, Ministry of Agriculture, Sericultural Research Institute, Chinese Academy of Agricultural Sciences, Zhenjiang, Jiangsu 212018, China.
Gene. 2019 Jul 30;707:109-116. doi: 10.1016/j.gene.2019.03.054. Epub 2019 Mar 31.
Ecdysone is involved in regulation of embryonic diapause in the silkworm, Bombyx mori. However, its mechanism still remains unclear. To explore the role of ecdysteroidogenic pathway (EP) genes in diapause process of bivoltine B. mori, the eggs of "Qiufeng", a bivoltine strain, were used as the study materials and arranged into diapause eggs producers (DEPs) and non-diapause eggs producers (NDEPs), respectively. The differential expression of EP genes between two groups was analysed during the early pupal stage. The expression of Shadow was significantly increased in the NDEPs in day-3 pupae and reached the peak simultaneously, indicating that Shadow was in coincidence with diapause process. To validate this hypothesis, a repression of Shadow by RNA interference was performed in day-2 pupae of NDEPs. The expression of Shadow was downregulated by RNAi, and βFtz-F1, a downstream gene of EP, was also decreased. Furthermore, the genes encoding the kynurenine-synthetase were upregulated in the ovary, and Brown, AdenoK which link Shadow to the kynurenine-synthase gene were also upregulated in the fat body. The progeny eggs appeared a light purple colour at 48 h after oviposition, revealing a certain tendency to diapause. We speculate that inhibition of Shadow upregulates 3-hydroxy-kynurenine synthesis by increasing the expression of Brown and AdenoK. In addition, Shadow was cloned, and expressed in E. coli for further functional study of Shadow protein. Our study provided insight into the role of EP genes in the process of diapause of B. mori.
蜕皮激素参与了家蚕的胚胎滞育调控。然而，其作用机制尚不清楚。为了探讨蜕皮甾醇生物合成途径（EP）基因在二化性家蚕滞育过程中的作用，以二化性品种“秋丰”的卵为研究材料，分别设置滞育卵发生者（DEPs）和非滞育卵发生者（NDEPs），分析早期蛹期两组间 EP 基因的差异表达。结果显示，在 3 日龄蛹中 NDEPs 组中 Shadow 基因的表达显著上调，并同时达到峰值，表明 Shadow 与滞育过程同步。为了验证这一假设，在 NDEPs 的 2 日龄蛹中通过 RNAi 抑制 Shadow 的表达。结果表明，Shadow 的表达被下调，其下游基因βFtz-F1 的表达也随之降低。此外，在卵巢中编码犬尿氨酸合成酶的基因上调，连接 Shadow 和犬尿氨酸合成酶基因的 Brown 和 AdenoK 在脂肪体中也上调。产卵后 48 小时，后代卵呈现淡紫色，显示出一定的滞育倾向。我们推测，抑制 Shadow 通过增加 Brown 和 AdenoK 的表达来上调 3-羟基犬尿氨酸的合成。此外，还克隆了 Shadow 基因，并在大肠杆菌中表达，以进一步研究 Shadow 蛋白的功能。本研究为揭示 EP 基因在家蚕滞育过程中的作用提供了新的思路。
