Differential expression of vitellogenin and oestrogen receptor genes in the liver of zebrafish, Danio Rerio
Differential expression of vitellogenin and oestrogen receptor genes in the liver of zebrafish, Danio Rerio
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DOI：
10.1007/s00216-009-3112-2
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发表时间：
2010-01-01
影响因子：
4.3
通讯作者：
Craft, John A.
中科院分区：
文献类型：
--
作者：
Meng, Xiang;Bartholomew, Chris;Craft, John A.
环境雌激素会对鱼类产生不利影响，影响繁殖。可用模型鱼来研究内源性和外源性雌激素的差异效应并测试化学物质的雌激素活性将是有利的。斑马鱼可以提供这样的模型，但卵黄原蛋白（VTG）和雌激素受体（ER）的组织和表达尚不完全清楚。 VTG 在肝脏中合成，并提供雌激素活性的敏感生物标志物，因为它们被认为受到 ER 的调节。 VTG 有多个基因，通过对其在斑马鱼基因组中分布的计算机分析确定了 6 个基因：VTG-1、VTG-2、VTG-4、VTG-5、VTG-7 位于 22 号染色体上，VTG-3 位于 11 号染色体上。开发了 VTG 特异性、定量、实时逆转录聚合酶链式反应测定法，并用于测量成熟雄性和雌性斑马鱼肝脏中的差异表达。雌鱼标准化后，VTG-5 mRNA 的相对表达量最高，分别比 VTG-4、VTG-2 和 VTG-1 高 1.3 倍、1.6 倍和 2 倍，而 VTG-3 和 VTG-7 的表达量非常低。雄鱼中 VTG 的表达要么无法检测到，要么非常低（VTG-4 和 VTG-5）。 ER α 和 ER β 2 在女性中的表达水平高于 ER β 1，但在男性中仅 ER β 2 表达量较高。雄性鱼中 ER α 的表达显着，但仅达到检测极限（雌性鱼< 0.1%），而无法检测到 ER β 1。雄性鱼中 ER α 的表达水平非常低，这引起了人们对雄性鱼中雌激素诱导 VTG 的公认机制的质疑。
Environmental oestrogens are responsible for adverse effects in fish that affect reproduction. Availability of model fish to study the differential effects of endogenous and exogenous oestrogens and to test for oestrogenic activity of chemicals would be advantageous. Zebrafish could provide such a model, but the organisation and expression of vitellogenins (VTGs) and oestrogen receptors (ERs) are not completely understood. VTGs are synthesised in the liver and provide a sensitive biomarker of oestrogenic activity since they are thought to be under the regulation of the ER. There are multiple genes for VTGs and an in silico analysis of their distribution in the Zebrafish genome has identified six genes: VTG-1, VTG-2, VTG-4, VTG-5, VTG-7 located on chromosome 22 and VTG-3 on chromosome 11. VTG-specific, quantitative, real-time, reverse-transcriptase polymerase chain reaction assays were developed and used to measure differential expression in the livers of mature male and female zebrafish. Following normalisation in female fish, relative expression of VTG-5 mRNA is highest and is 1.3x, 1.6x and 2x higher than VTG-4, VTG-2 and VTG-1, respectively, while expression of VTG-3 and VTG-7 is very low. Expression of VTGs in male fish was either undetectable or very low (VTG-4 and VTG-5). ER alpha and ER beta 2 were expressed at higher levels than ER beta 1 in females, but only ER beta 2 was expressed in appreciable quantity in males. Expression of ER alpha in males was significant but only at the limit of detection (< 0.1% of female fish), while ER beta 1 could not be detected. The very low level of expression of ER alpha in males raises questions about the accepted mechanism of oestrogenic induction of VTG in male fish.