Identification of six differentially expressed genes in response to copper exposure in the aquatic plant Lemna gibba (duckweed)
Identification of six differentially expressed genes in response to copper exposure in the aquatic plant Lemna gibba (duckweed)
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DOI：
10.1897/04-352r.1
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发表时间：
2005-07-01
影响因子：
4.1
通讯作者：
Greenberg, BM
中科院分区：
文献类型：
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作者：
Akhtar, TA;Lampi, MA;Greenberg, BM
水生植物容易受到金属污染，并为铜等金属进入水生生物圈提供了入口。水生植物 LeMna gibba 接触铜与活性氧 (ROS) 的产生和氧化损伤有关，这在很大程度上是由这种金属的氧化还原循环能力引起的。特别是，铜介导的 ROS（一组已知的信号分子）的产生会触发银杏的大量防御反应。因此，本研究的目的是检查急性铜暴露在多大程度上改变了基因表达。首先，评估铜吸收的动力学以确定同化是否发生在诱导基因表达所需的短暂暴露内。随后，使用差异显示聚合酶链式反应，我们鉴定了六个基因，其表达可能因铜的反应而改变。 Northern 杂交分析证实了差异表达，并表明铜会导致编码胼胝质、合酶、热休克蛋白 90、丝氨酸脱羧酶和乙酰辅酶 A 羧化酶的生物素羧化酶亚基的转录物积累。相反，除了叶绿体核状 DNA 结合蛋白 CND41 之外，铜还会导致编码血红素激活蛋白 (HAP) 转录因子 HAP5 亚基的基因转录水平下降。有趣的是。这些基因的表达对细胞活性氧水平敏感。我们相信这些基因产物提供了有关铜毒性分子机制的有价值的信息。
Aquatic plants are susceptible to metal pollution and provide an entry point for metals, such as copper, into the aquatic biosphere. Exposure of the aquatic plant LeMna gibba to copper has been associated with the production of reactive oxygen species (ROS) and oxidative damage, caused in large part by the ability of this metal to redox cycle. In particular, copper-mediated production of ROS, a known group of signaling molecules, triggers numerous defense responses in L. gibba. Therefore, the objective of the present study was to examine to what extent acute copper exposure alters gene expression. First, the kinetics of copper uptake was assessed to determine if assimilation occurred within the short exposures needed to induce gene expression. Subsequently, using differential display polymerase chain reaction, we identified six genes with expressions that were putatively altered in response to copper. Differential expression was confirmed by northern hybridization analysis and showed that copper causes an accumulation of transcripts that encode for callose, synthase, heat shock protein 90, serine decarboxylase, and the biotin carboxylase subunit of acetvl-coenzyme A carboxylase. Conversely, copper caused a decline in transcript levels for genes encoding the HAP5 subunit of the heme-activated protein (HAP) transcription factor in addition to the chloroplast nucleoid DNA-binding protein CND41. Interestingly. the expressions of these genes are sensitive to cellular ROS levels. We believe that these gene products provide valuable information regarding the molecular mechanisms of copper toxicity.