Effective inducing of ovarian maturation in female shrimp broodstock is important for successful breeding programs. Vitellogenesis is a biochemical process during which a yolk protein precursor vitellogenin (Vg) is synthesized and thus, can be used to indicate ovarian maturation stage. In this study, transcriptional regulation of Vg synthesis in the black tiger shrimp, Penaeus monodon was investigated. Genome walking on 5′ upstream sequence of Vg gene revealed several putative binding sites of lipophilic retinoic acid response elements (RARE), and nuclear hormone responsive elements. Deletion of RARE significantly reduced the promoter activity to drive the expression of luciferase reporter gene in Sf-9 cells. To validate the trans-factor that potentially controls Vg expression through RARE, a cDNA encoding retinoid X receptor (PmRXR), one of the RARE-bound transcription factors was cloned from P. monodon's ovary. PmRXR expression was detected in various shrimp tissues, and was up-regulated during ovary development in a similar way to Vg expression. The DNA-binding domain of PmRXR protein showed specific binding to RARE-containing region on Vg 5′ upstream sequence as determined by Electrophoretic Mobility Shift Assay (EMSA). Furthermore, dsRNA-mediated PmRXR silencing in previtellogenic and vitellogenic shrimp revealed that suppression of PmRXR could reduce Vg transcript in both stages. Taken together, the results presented in this study indicate that RXR is possibly an activator protein that modulates Vg expression in shrimp ovary through the binding to RARE.

有效诱导雌虾亲虾卵巢成熟对于成功的育种计划很重要。卵黄生成是一个生化过程，在此过程中合成了卵黄蛋白前体卵黄蛋白 (Vg)，因此可用于指示卵巢成熟阶段。本研究对斑节对虾Vg合成的转录调控进行了研究。在Vg基因的5' 上游序列上行走的基因组揭示了亲脂性视黄酸反应元件 (RARE) 和核激素反应元件的几个假定结合位点。RARE 的缺失显着降低了驱动 Sf-9 细胞中荧光素酶报告基因表达的启动子活性。验证可能控制Vg的反式因子通过 RARE 表达，一种编码类视黄醇 X 受体 ( PmRXR ) 的 cDNA，从斑节对虾的卵巢中克隆了一种与 RARE 结合的转录因子。在各种虾组织中检测到PmRXR表达，并且在卵巢发育过程中以类似于Vg表达的方式上调。PmRXR 蛋白的 DNA 结合域显示出与Vg 5' 上游序列上含有 RARE 的区域的特异性结合，如电泳迁移率变化测定 (EMSA) 所确定。此外，dsRNA 介导的PmRXR沉默在 previtellogenic 和 vitellogenic 虾中表明抑制PmRXR可以降低Vg两个阶段的成绩单。总之，本研究中呈现的结果表明 RXR 可能是一种激活蛋白，通过与 RARE 结合来调节虾卵巢中的Vg表达。