College of Horticulture and Plant Protection, Yangzhou University, Yangzhou 225009, China.
College of Horticulture and Plant Protection, Yangzhou University, Yangzhou 225009, China; Joint International Research Laboratory of Agriculture and Agri-Product Safety of the Ministry of Education, Yangzhou University, Yangzhou 225009, China.
J Insect Physiol. 2022 Jul;140:104405. doi: 10.1016/j.jinsphys.2022.104405. Epub 2022 Jun 6.
As the downstream effector of the target of rapamycin complex 1 (TORC1) signaling pathway, the ribosomal protein S6 kinase (S6K) is an important regulator of insect reproduction, however, the underlying mechanism remains obscure. In this study, a S6K gene, named TcS6K1, was isolated from the red flour beetle, Tribolium castaneum. Analysis of temporal and spatial expression patterns revealed that TcS6K1 is expressed at the highest level in the one-day-old first instar larvae and head of 7-day-old females, respectively. RNAi-mediated knockdown of TcS6K1 in either female or male adults decreased the number of eggs laid, with a concomitant reduction of mRNA levelsof vitellogenin genes, TcVg1 and TcVg2, two male accessory gland secretory proteins, as well as the juvenile hormone (JH) biosynthesis-related gene, farnesol dehydrogenase (TcFDH). While the mRNA and protein levels of the transcription factor forkhead box O (TcFOXO) were not affected, suppression of TcS6K1 expression promoted TcFOXO nuclear translocation to exert its transcriptional action. Further RNAi and EMSA analysis revealed that TcFOXO negatively regulated the expression of TcFDH. These results indicate that S6K might regulate beetles' reproduction through FOXO/JH signaling pathway.
作为雷帕霉素复合物 1 (TORC1) 信号通路的下游效应物，核糖体蛋白 S6 激酶 (S6K) 是昆虫生殖的重要调节因子，但其潜在机制尚不清楚。本研究从赤拟谷盗中分离出一个 S6K 基因，命名为 TcS6K1。时空表达模式分析表明，TcS6K1 在 1 日龄 1 龄幼虫和 7 日龄雌虫头部的表达水平最高。在雌虫或雄虫成虫中，通过 RNAi 敲低 TcS6K1 表达，产卵量减少，同时卵黄蛋白原基因 TcVg1 和 TcVg2、两种雄性附腺分泌蛋白以及法呢醇脱氢酶 (TcFDH) 的 mRNA 水平降低。尽管转录因子叉头框 O (TcFOXO) 的 mRNA 和蛋白水平不受影响，但 TcS6K1 表达的抑制促进了 TcFOXO 的核转位，从而发挥其转录作用。进一步的 RNAi 和 EMSA 分析表明，TcFOXO 负调控 TcFDH 的表达。这些结果表明，S6K 可能通过 FOXO/JH 信号通路调节甲虫的生殖。
