College of Animal Science and Technology, Northwest A&F University, Shaanxi Key Laboratory of Molecular Biology for Agriculture, Yangling, Shaanxi 712100, China; College of Animal Science and Technology, Yangzhou University, Yangzhou 225009, China.
College of Animal Science and Technology, Northwest A&F University, Shaanxi Key Laboratory of Molecular Biology for Agriculture, Yangling, Shaanxi 712100, China.
Ecotoxicol Environ Saf. 2018 Jan;147:423-429. doi: 10.1016/j.ecoenv.2017.09.001. Epub 2017 Sep 14.
Vitellogenins (Vtgs) are major precursor of the egg-yolk proteins. They are synthesized in liver of adult female ovipara, but normally silent in males. For their sensitive response to estrogen, Vtgs are usually used as biomarkers for environmental estrogenic compounds. In the present study, three vtg subtypes (vtg1, vtg2 and vtg3) were proved to present in the testis of rare minnow Gobiocypris rarus for the first time. Immunohistochemistry result showed that Vtg proteins mainly deposit in spermatogonium and spermatocytes. Following 225μg/L bisphenol A (BPA) exposure 1, 3 and 9 weeks, testicular vtg mRNAs were mostly significantly decreased. The further chromatin immunoprecipitation showed that BPA could decrease estrogen receptor (Er) recruitment in vtg promoter, which possibly reduced Er's transcription activation effect on vtgs. However, different from the continuously decreased vtg mRNA levels, testicular Vtg protein levels were recovered at week 9. Considering the induced hepatic Vtg expression, testicular Vtgs may be replenished by the induced hepatic Vtgs under BPA exposure.
卵黄蛋白原（Vtgs）是蛋黄蛋白的主要前体。它们在成年雌性产卵动物的肝脏中合成，但在雄性中通常处于沉默状态。由于其对雌激素的敏感反应，Vtgs 通常被用作环境雌激素化合物的生物标志物。在本研究中，首次证明稀有鲫 Gobiocypris rarus 的睾丸中存在三种 Vtg 亚型（vtg1、vtg2 和 vtg3）。免疫组织化学结果表明，Vtg 蛋白主要沉积在精原细胞和精母细胞中。在 225μg/L 双酚 A（BPA）暴露 1、3 和 9 周后，睾丸 vtg mRNAs 大多显著降低。进一步的染色质免疫沉淀表明，BPA 可以减少 vtg 启动子中雌激素受体（Er）的募集，从而可能降低 Er 对 vtgs 的转录激活作用。然而，与持续下降的 vtg mRNA 水平不同，睾丸 Vtg 蛋白水平在第 9 周时恢复。考虑到诱导的肝 Vtg 表达，睾丸 Vtgs 可能在 BPA 暴露下通过诱导的肝 Vtgs 得到补充。
