Gul Haji, Chen Xingyong, Geng Zhaoyu
College of Animal Science and Technology, Anhui Agricultural University, No. 130 Changjiang West Road, Hefei 230036, China.
Anhui Province Key Laboratory of Local Livestock and Poultry Genetic Resource Conservation and Bio-Breeding, Anhui Agricultural University, No. 130 Changjiang West Road, Hefei 230036, China.
Animals (Basel). 2021 Mar 9;11(3):744. doi: 10.3390/ani11030744.
The yolk is the principal part of the egg that contains vitamins, minerals, lipids, and proteins which are essential for embryo development and hatching. The egg yolk contains significant amounts of lipoproteins, triacylglycerides, and cholesterol, whose dynamics are indistinct during embryogenesis. The effects of cholesterol on the yolk protein abundance, intensity, and function are ill-defined during embryonic development. Using two-dimensional gel electrophoresis, eggs with respective high and low cholesterol protein abundance were investigated after 0, 2, 6, and 13 days of embryogenesis and further analyzed by matrix-assisted laser desorption/ionization time-of-flight tandem mass spectrometry. The results revealed that the vitellogenin proteins are the most abundant egg yolk protein that showed proximity and a high degree of variation in isoelectric point and molecular weight. The results demonstrated increased expression of vitellogenin-1 and vitellogenin-3 at two days and vitellogenin-2 protein at 13 days of embryogenesis in both egg types. The ovoinhibitor, immunoglobulin lambda light chain precursor, Ig-gamma (clone-36 chicken), and beta-2-glycoprotein-1 precursor proteins were significantly expressed in high cholesterol eggs while haptoglobin protein PIT-54 and vitelline membrane outer layer proteins intensities were significant in low cholesterol eggs at two days of embryogenesis. The high cholesterol eggs showed a modest increase in egg weight, yolk weight, albumen height, yolk color, and egg strength relative to the low cholesterol eggs. The gene ontology enrichment analysis revealed that the differentially expressed proteins such as vitellogenin proteins were involved in lipid transport and lipid localization biological processes and showed nutrient reservoir activity function. The ovotransferrin regulated the biological processes of plasminogen activation and extracellular matrix disassembly and characterized the anchored component of the plasma membrane. The ovoinhibitor protein was involved in response to mineralocorticoid and corticosterone biological processes whereas the vitellin membrane outer layer protein constituted the extracellular exosome, extracellular organelle, and membrane-bounded vesicle cellular components. Collectively, our study revealed yolk protein abundance, molecular function, cellular components, and biological processes and concluded that yolk protein intensities were significantly altered by cholesterol concentration.
蛋黄是鸡蛋的主要部分，含有对胚胎发育和孵化至关重要的维生素、矿物质、脂质和蛋白质。蛋黄含有大量的脂蛋白、三酰甘油和胆固醇，其在胚胎发生过程中的动态尚不明确。在胚胎发育过程中，胆固醇对蛋黄蛋白质丰度、强度和功能的影响尚不明确。使用二维凝胶电泳，在胚胎发生0、2、6和13天后，对胆固醇蛋白丰度分别高和低的鸡蛋进行了研究，并通过基质辅助激光解吸/电离飞行时间串联质谱进一步分析。结果显示，卵黄蛋白原是最丰富的蛋黄蛋白，在等电点和分子量上显示出相近性和高度变异性。结果表明，在两种类型的鸡蛋中，胚胎发生两天时卵黄蛋白原-1和卵黄蛋白原-3的表达增加，胚胎发生13天时卵黄蛋白原-2蛋白的表达增加。卵类黏蛋白抑制剂、免疫球蛋白λ轻链前体、Ig-γ（克隆-36鸡）和β-2-糖蛋白-1前体蛋白在高胆固醇鸡蛋中显著表达，而触珠蛋白PIT-54和卵黄膜外层蛋白强度在胚胎发生两天时在低胆固醇鸡蛋中显著。相对于低胆固醇鸡蛋，高胆固醇鸡蛋的蛋重、蛋黄重、蛋白高度、蛋黄颜色和蛋强度适度增加。基因本体富集分析表明，差异表达的蛋白质如卵黄蛋白原参与脂质转运和脂质定位生物学过程，并显示出营养储存活性功能。卵转铁蛋白调节纤溶酶原激活和细胞外基质分解的生物学过程，并表征质膜的锚定成分。卵类黏蛋白抑制剂蛋白参与盐皮质激素和皮质酮生物学过程的反应，而卵黄膜外层蛋白构成细胞外囊泡、细胞外细胞器和膜结合囊泡细胞成分。总体而言，我们的研究揭示了蛋黄蛋白的丰度、分子功能、细胞成分和生物学过程，并得出结论，胆固醇浓度显著改变了蛋黄蛋白强度。
