Ou Yao, Luo Qin, Zeng Wenhui, Tang Yiyun, Hu Jie, Liu Chun, Ma Yan, Xu Hanfu
State Key Laboratory of Resource Insects, College of Sericulture, Textile and Biomass Sciences, Southwest University, Chongqing 400715, China.
Chongqing Sericulture Science and Technology Research Institute, Chongqing 400715, China.
Insects. 2025 Apr 1;16(4):369. doi: 10.3390/insects16040369.
The steroid hormone 20-hydroxyecdysone (20E), which is known to regulate insect molting and metamorphosis, is crucial for the normal development of silk glands (SGs) in the silkworm . However, how the 20E signaling pathway and its core members function in the SG remains largely unclear. Here, we report that the orphan nuclear receptor BmHR3, a 20E-response factor, plays an essential role in regulating SG development and silk protein synthesis. First, we showed that tissue-specific overexpression and knockout result in severe developmental defects in posterior silk glands (PSGs). Second, we revealed that dysfunction in PSGs dramatically represses the transcription of silk fibroin protein-coding genes, thereby inhibiting fibroin protein synthesis. Finally, we confirmed that BmHR3 can regulate fibroin protein-coding gene expression via direct and indirect mechanisms. This study elucidates the vital function of BmHR3 in SG and provides valuable information for thoroughly understanding the regulatory roles of 20E signaling in specialized insect organs.
类固醇激素20-羟基蜕皮酮（20E）已知可调节昆虫的蜕皮和变态，对家蚕丝腺（SGs）的正常发育至关重要。然而，20E信号通路及其核心成员在丝腺中的功能仍 largely不清楚。在这里，我们报告孤儿核受体BmHR3，一种20E反应因子，在调节丝腺发育和丝蛋白合成中起重要作用。首先，我们表明组织特异性过表达和敲除会导致后部丝腺（PSGs）出现严重的发育缺陷。其次，我们揭示了PSGs功能障碍会显著抑制丝素蛋白编码基因的转录，从而抑制丝素蛋白的合成。最后，我们证实BmHR3可通过直接和间接机制调节丝素蛋白编码基因的表达。本研究阐明了BmHR3在丝腺中的重要功能，并为深入了解20E信号在昆虫特殊器官中的调节作用提供了有价值的信息。
