National Research Lab of Marine Molecular and Environmental Bioscience, Department of Chemistry, College of Natural Sciences, Hanyang University, Seoul, 133-791, South Korea.
Fish Physiol Biochem. 2012 Oct;38(5):1331-42. doi: 10.1007/s10695-012-9621-5. Epub 2012 Feb 25.
Metallothionein (MT) has been used extensively as a potential molecular biomarker to detect heavy metal pollution in aquatic organisms. In order to investigate the modulation effect of heavy metals and to establish suitable biomarkers for the monitoring of heavy metal pollution, Pelteobagrus fulvidraco metallothionein gene was characterized as the first report in the family Bagridae. Pf-MT transcript was detected at high levels in liver, gonad, kidney, and brain compared to other tissues. A time-course study in response to waterborne Cd (5 ppm) revealed that a significant increase in the Pf-MT transcript abundance was observed at 6 h in gill, kidney, and liver. These elevated levels were kept for 96 h, implying that Cd distributed fast into different organs and was involved in the tissue-specific induction pattern. We observed a significant Pf-MT transcript increase in liver tissues at 48 h, followed by gill at 12 h and intestine at 48 h after Cd exposure. This indicates hepatic MT expression as a potential biomarker of acute Cd exposure in this species. Cd-binding ability of recombinant Pf-MT protein provided evidence for sensitivity to Cd and other heavy metal exposure. In the case of Zn exposure (1 ppm), a significant increase in Pf-MT transcript abundance was observed at 12 h, and a peak induction level reaching sixfold at 24 h was kept until 48 h, showing similar transcript induction patterns with Cd. A high level of Pf-MT mRNA after exposure to Cu (1 ppm) was observed at 12 h that gradually increased until 96 h with a 12-fold induction, revealing a long-lasting induction and somewhat dissimilar pattern compared to other metals in liver. Our results demonstrate that Pf-MT can be induced by heavy metals in a tissue-specific and metal-specific manner and plays probably a conserved role in metal detoxification. This study provides new information on P. fulvidraco metallothionein gene for the use of biomarkers indicating metal pollution in fish.
金属硫蛋白（MT）已被广泛用作检测水生生物重金属污染的潜在分子生物标志物。为了研究重金属的调节作用，并建立适合重金属污染监测的生物标志物，本研究首次对黄颡鱼（Pelteobagrus fulvidraco）金属硫蛋白基因进行了特征描述。与其他组织相比，Pf-MT 转录本在肝脏、性腺、肾脏和大脑中表达水平较高。在对水载 Cd（5 ppm）的时程研究中，在鳃、肾脏和肝脏中观察到 Pf-MT 转录本丰度显著增加，在 6 h 时达到峰值。这些升高水平持续了 96 h，表明 Cd 快速分布到不同器官并参与了组织特异性诱导模式。我们观察到 Cd 暴露后 48 h 肝脏组织中 Pf-MT 转录本显著增加，随后 12 h 为鳃组织，48 h 为肠组织。这表明肝脏 MT 表达可能是该物种急性 Cd 暴露的潜在生物标志物。重组 Pf-MT 蛋白的 Cd 结合能力为其对 Cd 和其他重金属暴露的敏感性提供了证据。在 Zn 暴露（1 ppm）的情况下，在 12 h 时观察到 Pf-MT 转录本丰度显著增加，在 24 h 时达到六倍的峰值诱导水平，并持续到 48 h，表现出与 Cd 相似的转录诱导模式。在暴露于 1 ppm Cu 后，在 12 h 时观察到 Pf-MT mRNA 水平较高，随后一直增加到 96 h，诱导倍数为 12 倍，与肝脏中其他金属相比，呈现出持久诱导和有些不同的模式。我们的研究结果表明，Pf-MT 可以以组织特异性和金属特异性的方式被重金属诱导，并在金属解毒中可能发挥保守作用。本研究为黄颡鱼金属硫蛋白基因作为指示鱼类金属污染的生物标志物提供了新的信息。
