A novel CPx-ATPase from the cadmium hyperaccumulator Thlaspi caerulescens
A novel CPx-ATPase from the cadmium hyperaccumulator Thlaspi caerulescens
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DOI：
10.1016/j.febslet.2004.05.036
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发表时间：
2004-07-02
期刊：
影响因子：
3.5
通讯作者：
Verbruggen, N
中科院分区：
文献类型：
--
作者：
Bernard, C;Roosens, N;Verbruggen, N
蓝蓟具有独特的镉耐受和积累能力。我们通过筛选T. caerulescens基因，其在酿酒酵母中表达后减轻Cd 2+毒性。这允许分离编码与重金属ATP酶的C-末端部分具有同源性的肽的cDNA。从T. caerulescens的同源物，并与拟南芥（AtHMA 4）进行比较。TcHMA 4和AtHMA 4 cDNA的表达赋予酵母镉敏感性，而分别编码TcHMA 4和AtHMA 4的C-末端的TcHMA 4-C和AtHMA 4-C cDNA的表达赋予镉耐受性。此外，在酵母中的异源表达表明与AtHMA 4-C相比，TcHMA 4-C具有更高的Cd结合能力。在植物中，两个HMA 4基因在根中的表达水平高于在芽中的表达水平。然而，TcHMA 4显示出比AtHMA 4高得多的组成型表达。结果表明，HMA 4可能参与了Cd ~（2+）的转运，并可能参与了Cd的超积累特性。(C)2004年欧洲生物化学学会联合会。Elsevier B. V.出版，保留所有权利。
Thlaspi caerulescens exhibits a unique capacity for cadmium tolerance and accumulation. We investigated the molecular basis of this exceptional Cd2+ tolerance by screening for T. caerulescens genes, which alleviate Cd2+ toxicity upon expression in Saccharomyces cerevisiae. This allowed for the isolation of a cDNA encoding a peptide with homology to the C-terminal part of a heavy metal ATPase. The corresponding TcHMA4 full-length sequence was isolated from T. caerulescens and compared to its homolog from Arabidopsis thaliana (AtHMA4). Expression of TcHMA4 and AtHMA4 cDNAs conferred Cd sensitivity in yeast, while expression of TcHMA4-C and AtHMA4-C cDNAs encoding the C-termini of, respectively, TcHMA4 and AtHMA4 conferred Cd tolerance. Moreover, heterologous expression in yeast suggested a higher Cd binding capacity of TcHMA4-C compared to AtHMA4-C. In planta, both HMA4 genes were expressed at a higher level in roots than in shoots. However, TcHMA4 shows a much higher constitutive expression than AtHMA4. Our data indicate that HMA4 could be involved in Cd2+ transport and possibly in the Cd hyperaccumulation character. (C) 2004 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.