Cloning of three estrogen receptors (ER) from killifish (Fundulus heteroclitus):: Differences in populations from polluted and reference environments
Cloning of three estrogen receptors (ER) from killifish (Fundulus heteroclitus):: Differences in populations from polluted and reference environments
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DOI：
10.1016/j.ygcen.2006.07.017
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发表时间：
2007-01-01
影响因子：
2.7
通讯作者：
Callard, Gloria V.
中科院分区：
文献类型：
--
作者：
Greytak, Sarah R.;Callard, Gloria V.
流行病学、野生动物和实验室研究支持这样一种假设，即通过人类活动释放到环境中的化学品是生殖和发育异常的原因。虽然新贝德福德港（NBH）的鳉鱼种群已经成功地存活和繁殖了50年以上（类似于20代），但鱼类体内主要NBH污染物（多氯联苯）的负荷很高; P450芳香化酶B和卵黄蛋白原mRNA（雌激素效应的标志物）水平升高;以及内分泌干扰的证据。为了研究NBH鳉鱼雌激素反应系统可能的适应性变化，我们从居住在NBH和相对未受污染的参考地点（马萨诸塞州斯科顿溪，南卡罗来纳州）的鳉鱼种群中克隆了雌激素受体（ER）。分别鉴定了编码620、543和672个氨基酸的全长多肽的ER α、β α和β B b cDNA。每种ER亚型都有多种剪接变体、单核苷酸多态性（SNP）和特征性组织分布和发育概况。如通过实时定量RT-PCR分析所测量的，每个ER的整体组织分布在NBH和SC鱼中是相似的，这意味着维持组织特异性表达的调节途径在很大程度上不受长期污染物暴露的影响。尽管如此，一个显着的差异被认为是在雌激素诱导基因ER α，这是显着较低的大脑，肝脏和卵巢的生殖活跃NBH相比，SC女性的mRNA的量。奇怪的是，尽管“雌激素”NBH环境，ER α mRNA水平没有不同的生殖不活跃的NBH和SC女性，或男性在这两个网站在一年中的任何时间。我们解释的结果在NBH鱼部分是由于循环雌激素的赤字，部分是由于民意调查介导的ER α基因的低反应性。在显着的对比成鱼，ERa升高类似于5倍，在NBH相比，SC胚胎/幼虫，可能指示雌激素化学物质在蛋黄中。我们的结论是，NBH环境中的污染物影响雌激素信号通路的分子组成部分在居民？这些变化是短暂的还是可遗传的，还需要进一步研究。(c)2006年爱思唯尔公司All rights reserved.
Epidemiological, wildlife, and laboratory studies support the hypothesis that chemicals released into the environment through anthropogenic activities are responsible for abnormalities of reproduction and development. Although the New Bedford Harbor (NBH) killifish population has survived and reproduced successfully for > 50 yr (similar to 20 generations), fish have high body burdens of the major NBH contaminants (polychlorinated biphenyls); elevated levels of P450 aromatase B and vitellogenin mRNA (markers of estrogen effect); and evidence of endocrine disruption. To investigate possible adaptive changes in the estrogen response system of NBH killifish, we cloned the estrogen receptors (ER) from killifish populations resident in NBH and a relatively unpolluted reference site (Scorton Creek MA, SC). ER alpha, beta alpha, and -beta b cDNAs encoding full-length polypeptides of 620, 543, and 672 amino acids, respectively, were identified. Each ER subtype had Multiple splice variants, single nucleotide polymorphisms (SNPs), and a characteristic tissue distribution and developmental profile. As measured by real-time quantitative RT-PCR analysis, the overall tissue distribution of each ER was similar in NBH and SC fish, implying that the regulatory pathways which maintain tissue-specific expression are largely unchanged by long term pollutant exposure. Nonetheless, a striking difference was seen in the quantity of mRNA of the estrogen-inducible gene ER alpha, which was significantly lower in brain, liver and ovaries of reproductively active NBH as compared to SC females. Paradoxically, despite the "estrogenic" NBH environment, ER alpha mRNA levels did not differ in reproductively inactive NBH and SC females, or in males at the two sites at any time of year. We interpret results in NBH fish as due in part to a deficit of circulating estrogen, and in part to poll utant-mediated hyporesponsiveness of the ER alpha gene. In marked contrast to adult fish, ERa was elevated similar to 5-fold in NBH as compared to SC embryos/larvae, perhaps indicative of estrogenic chemicals in yolk. We conclude that contaminants in the NBH environment impact molecular components of the estrogen signaling pathways in resident killifish populations. Whether these changes are transient or heritable requires further study. (c) 2006 Elsevier Inc. All rights reserved.