Sun Zhongxiang, Shi Qi, Xu Cuicui, Wang Rumeng, Wang Huanhuan, Song Yuanyuan, Zeng Rensen
College of Crop Science, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
College of Life Science, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
Comp Biochem Physiol A Mol Integr Physiol. 2018 Nov;225:26-32. doi: 10.1016/j.cbpa.2018.06.009. Epub 2018 Jun 20.
The major yolk protein precursors (YPP) gene, vitellogenin (Vg), usually considered as a reproductive indicator and molecular marker for evaluating insect fecundity, is controlled by insect hormone (mainly ecdysteroids and juvenile hormone), transcription factors and many other fecundity-related genes. To better understand the underlying molecular regulation mechanisms of the NlVg in the brown planthopper Nilaparvata lugens (N. lugens), the correlation between one early ecdysone response gene E74 and one important fecundity-related gene angiotensin converting enzyme (ACE) on the regulation of Vg gene expression, was investigated. We first showed that the mRNA expression level of NlACE were significantly higher in a high-fecundity population (HFP) than a low-fecundity population (LFP) at different development stages, and knockdown of NlACE expression by RNA interference (RNAi) results in a reduced level of NlVg expression and N. lugens fecundity. Subsequently, we analyzed the promoter of NlACE and found an E74A binding site, which was also differentially expressed in HFP and LFP. Then a gene putatively encoding E74A, namely NlE74A, predominant in the ovary and fat body was cloned and characterized. Furthermore, the developmental profile during female adult and the tissue-specific expression pattern of NlACE and NlE74A were similar to the expression pattern of NlVg gene, implying that both NlACE and NlE74A may be involved in regulating the expression of NlVg. Finally, after injecting the dsRNA of NlE74A, the NlACE expression levels were significantly reduced simultaneously at 24 h and 48 h post-injection, and the NlVg expression level was significant reduced at 24 h post-injection and the downswing was more significant at 48 h post-injection. These results imply that regulation of NlE74A on NlVg transcription might be mediated by NlACE through the E74 binding site at the NlACE promoter region in N. lugens.
主要卵黄蛋白前体（YPP）基因，即卵黄原蛋白（Vg），通常被视为评估昆虫繁殖力的生殖指标和分子标记，它受昆虫激素（主要是蜕皮激素和保幼激素）、转录因子以及许多其他与繁殖力相关的基因调控。为了更好地理解褐飞虱（Nilaparvata lugens，N. lugens）中NlVg潜在的分子调控机制，研究了一个早期蜕皮激素反应基因E74和一个重要的与繁殖力相关的基因血管紧张素转换酶（ACE）对Vg基因表达调控的相关性。我们首先发现，在不同发育阶段，高繁殖力种群（HFP）中NlACE的mRNA表达水平显著高于低繁殖力种群（LFP），并且通过RNA干扰（RNAi）敲低NlACE的表达会导致NlVg表达水平和褐飞虱繁殖力降低。随后，我们分析了NlACE的启动子，发现了一个E74A结合位点，该位点在HFP和LFP中也存在差异表达。然后克隆并鉴定了一个推测编码E74A的基因，即NlE74A，其在卵巢和脂肪体中占主导地位。此外，雌性成虫期NlACE和NlE74A的发育谱以及组织特异性表达模式与NlVg基因的表达模式相似，这意味着NlACE和NlE74A可能都参与调控NlVg的表达。最后，注射NlE74A的dsRNA后，注射后24小时和48小时NlACE的表达水平同时显著降低，注射后24小时NlVg的表达水平显著降低，48小时下降更显著。这些结果表明，在褐飞虱中，NlE74A对NlVg转录的调控可能是通过NlACE在NlACE启动子区域的E74结合位点介导的。
