Li Shuang, Wang Jie, Cui Dongnan, Hao Kun, Chen Jun, Tu Xiongbing, Zhang Zehua
State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China.
School of Resources and Environmental Sciences, Henan Institute of Science and Technology, Xinxiang 453003, China.
Insects. 2021 Mar 17;12(3):253. doi: 10.3390/insects12030253.
Diapause is a physiological development arrest state that helps insects to adapt to seasonality and overcome adverse environmental conditions. Numerous reports have indicated that insulinlike and fork head transcription factor (FOXO) are involved in the regulation of diapause in insects. However, the upstream modulators of the insulin-like signaling pathway (ISP) involved in diapause regulation are still unknown. Here, we used RNAi and an inhibitor to treat PTK and PTP1B in adult tissues and injected Prx V or RNAi Prx V under both short and long photoperiod conditions and monitored effects on the expression of ISP genes, the phosphorylation levels for IR and IRS, the activity of NADPH oxidase, the accumulation of reactive oxygen species (ROS) and energy metabolism, seeking to identify both proteins and broader cellular metabolism influences on diapause regulation. We found that under short photoperiod conditions PTP1B in female adults induces egg diapause, whereas PTK in female adults inhibits egg diapause. Intriguingly, we also found that the antioxidant enzyme Prx V is a negative regulator of NADPH oxidizing reaction and apparently decreases ROS production and NADPH-OX activity. In contrast, all the eggs laid by adults that were treated with a series of knockdown or purified-protein injection experiments or inhibitor studies and that were reared under long photoperiod conditions hatched successfully. Thus, our results suggest a mechanism wherein diapause-related proteins (PTP1B, PTK, and Prx V) of female adults are the upstream modulators that regulate offspring eggs' diapause process through the insulin-like signaling pathway under short photoperiod conditions.
滞育是一种生理发育停滞状态，有助于昆虫适应季节性变化并克服不利的环境条件。大量报告表明，类胰岛素和叉头转录因子（FOXO）参与昆虫滞育的调控。然而，参与滞育调控的胰岛素样信号通路（ISP）的上游调节因子仍不清楚。在此，我们使用RNA干扰和一种抑制剂处理成年组织中的蛋白酪氨酸激酶（PTK）和蛋白酪氨酸磷酸酶1B（PTP1B），并在短光周期和长光周期条件下注射过氧化物酶V（Prx V）或RNA干扰Prx V，监测其对ISP基因表达、胰岛素受体（IR）和胰岛素受体底物（IRS）磷酸化水平、烟酰胺腺嘌呤二核苷酸磷酸氧化酶（NADPH氧化酶）活性、活性氧（ROS）积累以及能量代谢的影响，旨在确定对滞育调控有影响的蛋白质和更广泛的细胞代谢。我们发现，在短光周期条件下，雌性成虫中的PTP1B诱导卵滞育，而雌性成虫中的PTK抑制卵滞育。有趣的是，我们还发现抗氧化酶Prx V是NADPH氧化反应的负调节因子，明显降低ROS的产生和NADPH氧化酶活性。相比之下，通过一系列基因敲低、纯化蛋白注射实验或抑制剂研究处理并在长光周期条件下饲养的成虫所产的所有卵都成功孵化。因此，我们的结果表明了一种机制，即雌性成虫中与滞育相关的蛋白质（PTP1B、PTK和Prx V）是上游调节因子，在短光周期条件下通过胰岛素样信号通路调节后代卵的滞育过程。
