Zn/Cd超富集植物天蓝遏蓝菜(Thlaspi caerulescens)中TcCaM2基因的克隆及在酵母中的重金属耐受性分析 |
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作者姓名: | 韩璐 魏嵬 官子楸 徐进 柴团耀 |
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作者单位: | 中国科学院研究生院生物系, 北京100049 |
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摘 要: | 从重金属超富集植物天蓝遏蓝菜(T. caerulescens)Cd胁迫的cDNA文库中,通过基因表达的差异筛选得到的阳性克隆之一,核苷酸序列分析表明与拟南芥CaM2的相似性高达92%,故命名为TcCaM2(T. caerulescens CaM2, GenBank No. EF053035)。其核苷酸序列与迄今已知的钙调蛋白基因同源率在83%以上,其氨基酸序列同源性高达95%以上,与大多数高等植物的CaM,如印度芥菜、拟南芥、水稻等同源性则更高。将TcCaM2基因置于酵母表达启动子之下,构建酵母表达载体,并将其转入重金属敏感型酵母突变菌株,酵母重金属耐受实验表明,TcCaM2在酵母中的过量表达提高了酵母对Co2+或Ni2+的耐受性,增加了对Cd2+的敏感性,对Zn2+胁迫抗性稍有增加但差异不显著;说明TcCaM2通过其对重金属离子的结合作用及在信号转导系统中的功能,在植物细胞对重金属的富集、耐性中发挥了重要的调节作用。
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关 键 词: | TcCaM2 重金属 钙调蛋白(CaM) 天蓝遏蓝菜 酵 母 |
A Novel CAM gene from heavy metals hyperaccumulator Thlaspi caerulescens L. and Functional Analysis in yeas |
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Authors: | HAN Lu WEI Wei GUAN Zi-Qiu XU Jin CHAI Tuan-Yao |
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Institution: | Department of Biology, Graduate University of Chinese Academy of Sciences, Beijing 100049, China |
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Abstract: | Calmodulin, the predominant calcium receptor, is one of the best-characterized calcium sensors in eukaryotes which regulates diverse cellular functions by modulating the activity of a variety of enzymes and proteins. Research workers have evidences suggesting Ca2+ and calmodulin are involved in various environment stimulation reaction. By differential screen, we isolated a positive clone in the T.caerulescens cDNA library induced in response to Cd2+. The result of cDNA sequence analysis showed that the positive clone shared more than 92 % homologies for nucleotide sequences with CaM2 gene from Arabidopsis thanliana, named TcCaM2. The TcCaM2 gene consists of 447 nucleotides and encodes 149 amino acids, and it shares more than 83 % homologies for nucleotide sequences and 95 % for encoding amino acid sequences as compared with those of calmodulin genes of other plants. A yeast-expressed plasmid with TcCaM2 was constructed and transferred into heavy metal sensitive yeast mutant cells. Further study about the growth patterns of TcCaM2 -expressed yeast indicated that over expression of TcCaM2 improved Co2+、Ni2+ resistance and increased Cd2+ hypersensitivity in the yeast cells. As an important role in the T.caerulescens’s response to heavy metal, TcCaM2 can work as a significant gene tool in the phytoremediation of heavy metal pollution. |
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Keywords: | TcCaM2 heavy metal calmodulin(CaM) Thlaspi caerulescens yeast |
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