Jiangsu Key Laboratory for Biodiversity and Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing 210046, China.
Jiangsu Key Laboratory for Biodiversity and Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing 210046, China.
J Insect Physiol. 2022 Oct;142:104429. doi: 10.1016/j.jinsphys.2022.104429. Epub 2022 Aug 11.
Eclosion hormone (EH) is a neurohormone that plays a key role in the regulation of insect pre-ecdysis behavior at the end of each molt. Previous research has reported more than one EH gene was found in certain insects, with their functions and mechanisms still unclear. Here, aside from the classical EH gene orthologous group, we characterized another novel orthologous cluster of eclosion hormone-like (EHL) genes in Arthropoda and investigated the roles of EHL during development in Tribolium castaneum. T. castaneum EHL (TcEHL) shows high expression levels during pupal - adult development, which also positively responded to 20-hydroxyecdysone (20E) treatment as well as RNA interference (RNAi) of ECR (20E nuclear receptor). Knockdown of TcEHL prevented the tanning of the adult cuticle and caused lethal phenotypes. Further analysis indicated that knockdown of TcEHL could upregulate expression levels of the classical TcEH, and downregulate the ecdysis behavior cascade genes, as well as tanning pathway enzymes. This suggests a critical role for TcEHL in adult eclosion and cuticle tanning. In addition, our data indicated that TcEHL is responsible for the female reproduction process. Taken together, these results suggest that TcEHL has specific roles in adult cuticle tanning during the post-eclosion process and female reproduction. They also suggest that EHL gene is the ancestral copy for the EH family and it is functionally shuffled by synfunctionalization.
蜕皮激素（EH）是一种神经激素，在昆虫每次蜕皮结束时调节蜕皮前行为中起着关键作用。以前的研究报告称，某些昆虫中发现了不止一种 EH 基因，但其功能和机制尚不清楚。在这里，除了经典的 EH 基因直系同源群外，我们还在节肢动物中鉴定了另一个新的蜕皮激素样（EHL）基因直系同源簇，并研究了 EHL 在三化螟发育过程中的作用。T. castaneum EHL（TcEHL）在蛹-成虫发育过程中表达水平较高，对 20-羟基蜕皮酮（20E）处理以及 ECR（20E 核受体）的 RNA 干扰（RNAi）也呈正响应。TcEHL 的敲低阻止了成虫外骨骼的鞣制，并导致致命表型。进一步的分析表明，TcEHL 的敲低可以上调经典 TcEH 的表达水平，并下调蜕皮行为级联基因以及鞣制途径酶。这表明 TcEHL 在成虫蜕皮和外骨骼鞣制中起着关键作用。此外，我们的数据表明 TcEHL 负责雌性生殖过程。总之，这些结果表明 TcEHL 在蜕皮后过程中的成虫外骨骼鞣制和雌性生殖中具有特定作用。它们还表明 EHL 基因是 EH 家族的原始拷贝，并且通过功能改组而具有功能。
