【摘要】 为探索大口黑鲈（Micropterus salmoides）雌激素受体esr2a与esr2b基因的潜在免疫功能和作用机制，克隆了大口黑鲈esr2a与esr2b基因的cDNA片段，分析了其序列特征、表达模式、对注射诺卡氏菌（Nocardia seriolae）、大口黑鲈蛙虹彩病毒（largemouth bass virus, LMBV）及聚胞肌酸Poly I:C的时序性表达及对外源性激素17β-雌二醇（E₂）处理的响应。结果表明：获得的esr2a基因cDNA序列长度为1 912 bp,其中3′-非编码区（UTR）为113 bp, 5′UTR为125 bp,开放阅读框为1 674 bp,共编码557个氨基酸；克隆获得的esr2b基因cDNA序列长度为2 358 bp,其中3′UTR为293 bp, 5′UTR为52 bp,开放阅读框为2 013 bp,共编码670个氨基酸；大口黑鲈esr2a与esr2b蛋白均是一种稳定性较差、亲水性较强的酸性蛋白；它们均具有1个ZnF＿C4结构域和1个HOLI结构域；通过荧光定量PCR（real time quantitative PCR,RT-qPCR）分析发现，在正常鱼体中，esr2a基因在肾中显著高表达，esr2b基因在脾和肝中显著高表达，通过体内注射诺卡氏菌后，发现可以引起esr2a与esr2b基因在大口黑鲈肝表达量显著下降（P<0.05）;注射LMBV后，esr2a与esr2b基因在肾中的表达量显著提高（P<0.05）;而注射Poly I:C后，其可显著抑制esr2a与esr2b在肾与脾的表达（P<0.05）;此外，E₂处理均能抑制esr2a与esr2b基因在雌雄鱼中脾的表达（P<0.05）。研究表明，esr2a与esr2b基因可能与大口黑鲈免疫反应相关。更多还原

【Abstract】 Estrogen receptors play a crucial role in the reproductive processes of teleost fish. Recent studies have indicated that estrogen signaling pathways are related to immune responses of fish. To investigate the potential immune functions of the estrogen receptor genes 2a（esr2a） and 2b（esr2b） of the largemouth bass（Micropterus salmoides）, cDNA fragments of the esr2a and esr2b genes were isolated and their sequence characteristics were analyzed. Expression patterns and temporal expression profiles after injection with Nocardia seriolae, Largemouth bass virus（LMBV）, and polyinosinic-polycytidylic acid（Poly I:C）, as well as treatment with the exogenous hormone 17β estradiol（E₂） were explored.The cDNA sequence of the esr2a gene was 1 912 bp in length, with a 3′untranslated region（UTR） of 113 bp, a 5′UTR of 125 bp, and an open reading frame（ORF） of 1 674 bp, encoding a total of 557 amino acids. The cDNA sequence of the esr2b gene was 2 358 bp in length, with a 3′UTR of 293 bp, a 5′UTR of 52 bp, and an ORF of 2 013 bp, encoding a total of 670 amino acids.Both the esr2a and esr2b proteins in the largemouth bass were characterized as unstable, hydrophilic, and acidic. In addition, both esr2a and esr2b contained one ZnF＿C4 domain and one HOLI domain. Real-time fluorescence quantitative PCR analysis showed that, in normal fish, the esr2a gene exhibited its highest expression in kidney, while the esr2b gene showed its highest levels in spleen and liver. Following injection with N. seriolae, significant decreases in the expression levels of the esr2a and esr2b genes were observed in the liver of largemouth bass（P<0.05）. Conversely, after injection with LMBV, the expression levels of the esr2a and esr2b genes in the kidney increased significantly（P<0.05）. In contrast, injection with Poly I:C significantly inhibited the expression of esr2a and esr2b in both the kidney and spleen（P<0.05）. Additionally, E₂ treatment inhibited the expression of the esr2a and esr2b mRNAs in the spleens of both male and female fish（P<0.05）. This study suggests a potential association between the esr2a and esr2b genes and the immune response in largemouth bass.更多还原