From Tetrahymena thermophila （strain BF5）, the coding region of Cd-MT gene was cloned and sequenced. and identified as MTT1 isoform. A serial duplicate structure is discovered in its amino acid sequence, which separ...From Tetrahymena thermophila （strain BF5）, the coding region of Cd-MT gene was cloned and sequenced. and identified as MTT1 isoform. A serial duplicate structure is discovered in its amino acid sequence, which separates the coding region into three parts （Part 1：7-61; Part 2：64-118; Part 3：122-162）. The alignments among them and comparison with the corresponding parts of MT1 isoform suggest that MT1 and MTT1 isoforms both come from the same ancient gene that is homologous to Part 1, and Cd-MTs of Tetrahymena are aroused by such ancient gene duplication. The prediction of secondary structures and the analysis of the disulfide-bonding state of cysteine show that there are a lot of differences between MT1 and MTT1 isoforms, which maybe relate to their function mechanism.展开更多
金属硫蛋白(metallothionein,MT)MT3是人体中参与重金属解毒的主要蛋白,前期研究表明啤酒酵母(Saccharomyces c erevisiae)α因子信号肽(MF-α)介导重组蛋白EGFP分泌到植物体外。但是目前还没有研究报道转基因植物中过量表达分泌型MT3...金属硫蛋白(metallothionein,MT)MT3是人体中参与重金属解毒的主要蛋白,前期研究表明啤酒酵母(Saccharomyces c erevisiae)α因子信号肽(MF-α)介导重组蛋白EGFP分泌到植物体外。但是目前还没有研究报道转基因植物中过量表达分泌型MT3对植物重金属镉(Cd)的富集能力是否有影响。本研究通过人工方法合成MF-α信号肽、增强型绿色荧光蛋白(enhanced green fluorescent protein,EGFP)和MT3的融合基因MF-α-EGFP-MT3,构建该融合基因的植物表达载体pK-35S-MF-α-EGFP-MT3,转化野生型(WT)烟草和天竺葵获得转基因植物。通过电化学方法检测转基因植物MT3转录水平、转基因植物根系分泌液中EGFP-MT3蛋白的水平。用Cd溶液处理转基因植物,通过表型观察和电化学方法检测根、茎和叶中Cd的含量。结果表明,转基因烟草和天竺葵中都有MT3基因的转录;且根系分泌EGFP-MT3蛋白的量大约为0.45~0.68 mg·g-1(以鲜质量计)。100μmol·L-1的Cd溶液处理转基因烟草植株,表型变化分析发现转基因植株受损情况低于WT,近根部叶片叶绿素含量显著高于WT,说明EGFP-MT3的分泌可降低Cd的毒害作用。转基因烟草植株根、茎和叶片对Cd的富集量比WT高约40%。用50μmol·L-1的Cd溶液处理转基因天竺葵植株,结果表明转基因植株根对Cd的富集量比WT高约30%,茎对Cd的富集量比WT高约4倍。以上结果证明过量表达EGFP-MT3可以提高转基因烟草和天竺葵对Cd的富集能力,可能是EGFP-MT3分泌根系表面增加转基因植物根系对Cd的吸附作用,同时在转基因植物组织细胞内积累的EGFP-MT3也可增加植物组织对Cd的富集作用。展开更多
Industrial activities such as smelting emissions,mineral combustion and industrial wastewater discharge might lead to copper pollution in the environment.This kind of copper pollution has harmful effects on aquatic o ...Industrial activities such as smelting emissions,mineral combustion and industrial wastewater discharge might lead to copper pollution in the environment.This kind of copper pollution has harmful effects on aquatic o rganisms,plants and animals through direct or indirect exposure.However,the current understanding of the toxicity of copper is rather limited.Copper overload can perturb intracellular homeostasis and induce oxidative stress and e ven cell death.Recently,cuproptosis has been identified as a copper-dependent form of cell death induced by o xidative stress in mitochondria.We uncover here that zinc transporter 1(ZNT1)is an important regulator involved in cuproptosis.Firstly,we established the copper overload-induced cell death model with the overexpression of copper importer SLC31A1 in HeLa cells.Using this model,we conducted unbiased genome-wide CRISPR-Cas9 screens in cells treated with copper.Our results revealed a significant enrichment of ZNT1 gene in both library A and library B plasmids.Knocking out of ZNT1 in HeLa cells notably prevented cuproptosis.Subsequent knockout of metal transcription factor 1(MTF1)in ZNT1-deficient cells nearly abolished their ability to resist copper-induced cell death.However,overexpression of metallothionein 1X(MT1X)in the double-knockout cells could p artially restored the resistance to cuproptosis by loss of MTF1.Mechanistically,knockout of ZNT1 could promote MT1X expression by activating MTF1.As a consequence,the interaction between MT1X and copper was e nhanced,reducing the flow of copper into mitochondria and eliminating mitochondria damage.Taken together,this study reveals the important role of ZNT1 in cuproptosis and shows MTF1-MT1X axis mediated resistance to c uproptosis.Moreover,our study will help to understand the regulatory mechanism of cellular and systemic copper homeostasis under copper overload,and present insights into novel treatments for damages caused by both genetic copper overload diseases and environmental copper contamination.展开更多
文摘From Tetrahymena thermophila （strain BF5）, the coding region of Cd-MT gene was cloned and sequenced. and identified as MTT1 isoform. A serial duplicate structure is discovered in its amino acid sequence, which separates the coding region into three parts （Part 1：7-61; Part 2：64-118; Part 3：122-162）. The alignments among them and comparison with the corresponding parts of MT1 isoform suggest that MT1 and MTT1 isoforms both come from the same ancient gene that is homologous to Part 1, and Cd-MTs of Tetrahymena are aroused by such ancient gene duplication. The prediction of secondary structures and the analysis of the disulfide-bonding state of cysteine show that there are a lot of differences between MT1 and MTT1 isoforms, which maybe relate to their function mechanism.
文摘金属硫蛋白(metallothionein,MT)MT3是人体中参与重金属解毒的主要蛋白,前期研究表明啤酒酵母(Saccharomyces c erevisiae)α因子信号肽(MF-α)介导重组蛋白EGFP分泌到植物体外。但是目前还没有研究报道转基因植物中过量表达分泌型MT3对植物重金属镉(Cd)的富集能力是否有影响。本研究通过人工方法合成MF-α信号肽、增强型绿色荧光蛋白(enhanced green fluorescent protein,EGFP)和MT3的融合基因MF-α-EGFP-MT3,构建该融合基因的植物表达载体pK-35S-MF-α-EGFP-MT3,转化野生型(WT)烟草和天竺葵获得转基因植物。通过电化学方法检测转基因植物MT3转录水平、转基因植物根系分泌液中EGFP-MT3蛋白的水平。用Cd溶液处理转基因植物,通过表型观察和电化学方法检测根、茎和叶中Cd的含量。结果表明,转基因烟草和天竺葵中都有MT3基因的转录;且根系分泌EGFP-MT3蛋白的量大约为0.45~0.68 mg·g-1(以鲜质量计)。100μmol·L-1的Cd溶液处理转基因烟草植株,表型变化分析发现转基因植株受损情况低于WT,近根部叶片叶绿素含量显著高于WT,说明EGFP-MT3的分泌可降低Cd的毒害作用。转基因烟草植株根、茎和叶片对Cd的富集量比WT高约40%。用50μmol·L-1的Cd溶液处理转基因天竺葵植株,结果表明转基因植株根对Cd的富集量比WT高约30%,茎对Cd的富集量比WT高约4倍。以上结果证明过量表达EGFP-MT3可以提高转基因烟草和天竺葵对Cd的富集能力,可能是EGFP-MT3分泌根系表面增加转基因植物根系对Cd的吸附作用,同时在转基因植物组织细胞内积累的EGFP-MT3也可增加植物组织对Cd的富集作用。
文摘Industrial activities such as smelting emissions,mineral combustion and industrial wastewater discharge might lead to copper pollution in the environment.This kind of copper pollution has harmful effects on aquatic o rganisms,plants and animals through direct or indirect exposure.However,the current understanding of the toxicity of copper is rather limited.Copper overload can perturb intracellular homeostasis and induce oxidative stress and e ven cell death.Recently,cuproptosis has been identified as a copper-dependent form of cell death induced by o xidative stress in mitochondria.We uncover here that zinc transporter 1(ZNT1)is an important regulator involved in cuproptosis.Firstly,we established the copper overload-induced cell death model with the overexpression of copper importer SLC31A1 in HeLa cells.Using this model,we conducted unbiased genome-wide CRISPR-Cas9 screens in cells treated with copper.Our results revealed a significant enrichment of ZNT1 gene in both library A and library B plasmids.Knocking out of ZNT1 in HeLa cells notably prevented cuproptosis.Subsequent knockout of metal transcription factor 1(MTF1)in ZNT1-deficient cells nearly abolished their ability to resist copper-induced cell death.However,overexpression of metallothionein 1X(MT1X)in the double-knockout cells could p artially restored the resistance to cuproptosis by loss of MTF1.Mechanistically,knockout of ZNT1 could promote MT1X expression by activating MTF1.As a consequence,the interaction between MT1X and copper was e nhanced,reducing the flow of copper into mitochondria and eliminating mitochondria damage.Taken together,this study reveals the important role of ZNT1 in cuproptosis and shows MTF1-MT1X axis mediated resistance to c uproptosis.Moreover,our study will help to understand the regulatory mechanism of cellular and systemic copper homeostasis under copper overload,and present insights into novel treatments for damages caused by both genetic copper overload diseases and environmental copper contamination.
