Cloning, characterization, and gene expression analysis of a novel cadmium metallothionein gene in Tetrahymena pigmentosa
Cloning, characterization, and gene expression analysis of a novel cadmium metallothionein gene in Tetrahymena pigmentosa
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色素四膜虫中新型镉金属硫蛋白基因的克隆、表征和基因表达分析
DOI：
10.1016/j.gene.2008.04.023
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发表时间：
2008-10-15
期刊：
影响因子：
3.5
通讯作者：
Miao, Wei
中科院分区：
文献类型：
--
作者：
Guo, Lina;Fu, Chengjie;Miao, Wei
从纤毛虫着色四膜虫（Tetrahymena pigmentosa）中克隆了一个新的镉诱导型金属硫蛋白（MT）基因（Tpig-MT 1）。推导的氨基酸序列为118个。该多肽具有典型的四膜虫Cd诱导型MT的CCC和CC簇特征。Tpig-MT 1的结构不同于已报道的T. pyriformis，T. thermophila和T.色素沉着。Tpig-MT1包含两个基因内串联重复序列，其具有72.9%的同一性，被描述为Tpig-MT1（重复序列A1）和Tpig-MT1（重复序列A2）。采用实时荧光定量PCR技术检测了Tpig-MT1基因对不同重金属（Cd、Cu、Zn、Hg、Pb）和氧化胁迫（H2O2）的转录响应。结果表明，该基因在5种重金属胁迫下均能快速诱导表达（1 h），其表达量大小顺序为Hg> Pb> Cd> Cu> Zn。H_2O_2的诱导作用在约15 min后为5倍，但很快下降至不显著水平（30 min）。四膜虫MT基因的遗传多样性进行了讨论，在Tpig-MT1基因的独特结构和其他报告的镉-MT亚型。(C)2008 Elsevier B.V.保留所有权利。
A novel cadmium-inducible metallothionein (MT) gene (Tpig-MT1) was cloned and sequenced from the ciliate Tetrahymena pigmentosa. The number of deduced amino acids is 118. The polypeptide possesses CCC and CC clusters characteristic of typical Tetrahymena Cd-inducible MTs. The structure of Tpig-MT1 is different from the reported Cd-MT in T. pyriformis, T. thermophila and T. pigmentosa. Tpig-MT1 contains two intragenic tandem repeats with 72.9% identity described as Tpig-MT1 (repeat A1) and Tpig-MT1 (repeat A2). The transcriptional response of Tpig-MT1 gene to different heavy metals (Cd, Cu, Zn, Hg, Pb) and oxidative stress (H2O2) was measured using real-time quantitative PCR. The results showed that the gene was quickly induced (1 h) by the five heavy metals and the order of expression level was Hg>Pb>Cd>Cu>Zn. The induction effect of H2O2 was 5-fold after about 15 min, but soon decreased to a non-significant level (30 min). The genetic diversity of Tetrahymena MT genes is discussed in relation to the unique structure of the Tpig-MT1 gene and other reported Cd-MT isoforms. (C) 2008 Elsevier B.V. All rights reserved.