Zhang Ruidong, Hu Yuehong, Wang Huan, Yan Peng, Zhou Yongkang, Wu Rong, Wu Xiaobing
Key Laboratory for Conservation and Use of Important Biological Resources of Anhui Province, College of Life Sciences, Anhui Normal University, Wuhu, Anhui 241000, People's Republic of China.
Alligator Research Center of Anhui Province, Xuanzhou 242000, People's Republic of China.
Comp Biochem Physiol B Biochem Mol Biol. 2016 Oct;200:28-35. doi: 10.1016/j.cbpb.2016.05.001. Epub 2016 May 20.
Chinese alligator, Alligator sinensis, is a critically endangered reptile species unique to China. Little is known about the mechanism of growth- and reproduction-related hormones gene expression in Chinese alligator. Estrogens play important roles in regulating multiple reproduction- and non-reproduction-related functions by binding to their corresponding receptors. Here, the full-length cDNA of estrogen receptor alpha (ERα/ESR1) was cloned and sequenced from Chinese alligator for the first time, which comprises 1764bp nucleotides and encodes a predicted protein of 587 amino acids. Phylogenetic analysis of ESR1 showed that crocodilians and turtles were the sister-group of birds. The results of real-time quantitative PCR indicated that the ESR1 mRNA was widely expressed in the brain and peripheral tissues. In the brain and pituitary gland, ESR1 was most highly transcribed in the cerebellum. But in other peripheral tissues, ESR1 mRNA expression level was the highest in the ovary. Compared with hibernation period, ESR1 mRNA expression levels were increased significantly in the reproductive period (P<0.05) in cerebellum, pituitary gland, liver, spleen, lung, kidney and ovary, while no significant change in other examined tissues (P>0.05). The ESR1 mRNA expression levels changes during the two periods of different tissues suggested that ESR1 might play an important role in mediation of estrogenic multiple reproductive effects in Chinese alligator. Furthermore, it was the first time to quantify ESR1 mRNA level in the brain of crocodilians, and the distribution and expression of ESR1 mRNA in the midbrain, cerebellum and medulla oblongata was also reported for the first time in reptiles.
扬子鳄（Alligator sinensis）是中国特有的极度濒危爬行动物物种。关于扬子鳄生长和繁殖相关激素基因表达的机制，人们了解甚少。雌激素通过与其相应受体结合，在调节多种与繁殖和非繁殖相关的功能中发挥重要作用。在此，首次从扬子鳄中克隆并测序了雌激素受体α（ERα/ESR1）的全长cDNA，其包含1764个核苷酸，编码一个预测的由587个氨基酸组成的蛋白质。ESR1的系统发育分析表明，鳄类和龟类是鸟类的姐妹群。实时定量PCR结果表明，ESR1 mRNA在大脑和外周组织中广泛表达。在大脑和垂体中，ESR1在小脑中转录水平最高。但在其他外周组织中，ESR1 mRNA表达水平在卵巢中最高。与冬眠期相比，在繁殖期，小脑、垂体、肝脏、脾脏、肺、肾脏和卵巢中的ESR1 mRNA表达水平显著升高（P<0.05），而在其他检测组织中无显著变化（P>0.05）。不同组织在两个时期的ESR1 mRNA表达水平变化表明，ESR1可能在介导雌激素对扬子鳄的多种繁殖效应中发挥重要作用。此外，这是首次对鳄类大脑中的ESR1 mRNA水平进行定量，并且首次报道了爬行动物中ESR1 mRNA在中脑、小脑和延髓中的分布和表达情况。
