高浓度氯化镍胁迫下酿酒酵母组蛋白H4K5去乙酰化调控金属硫蛋白基因的表达  

Deacetylation of histone H4K5 regulates the expression of metallothionein genes under high concentration of nickel chloride in Saccharomyces cerevisiae

作　　者：郭艳飞 黄勇霖 张苗苗 蔡禄 赵秀娟 GUO Yanfei;HUANG Yonglin;ZHANG Miaomiao;CAI Lu;ZHAO Xiujuan(School of Life Science and Technology,Inner Mongolia University of Science and Technology,Baotou 014010,China)

机构地区：[1]内蒙古科技大学生命科学与技术学院,包头014010

出　　处：《应用与环境生物学报》2020年第3期551-557,共7页Chinese Journal of Applied and Environmental Biology

基　　金：国家自然科学基金项目(21767020,61361014);内蒙古自然科学基金项目(2019MS02021)资助。

摘　　要：金属硫蛋白(MTs)具有重金属解毒功能.组蛋白乙酰化/去乙酰化是表观遗传因子之一,并且参与基因的表达调控.然而,组蛋白乙酰化/去乙酰化在真核生物响应氯化镍胁迫过程中对金属硫蛋白基因的调控作用还不清楚.以酿酒酵母突变株H4K5R(该菌株模拟组蛋白H4赖氨酸5去乙酰化的状态)为试验材料,采用流式细胞术检测不同浓度氯化镍处理下酵母细胞的死亡率,发现突变菌株的生长状态和细胞存活率明显优于野生型菌株BY4741;qRT-PCR检测5 mmol/L氯化镍处理后,酿酒酵母金属硫蛋白基因Cup1、Crs5、Sod1及转录因子Cup2的表达量.结果显示,高浓度氯化镍胁迫下,野生型菌株中基因的表达水平均显著降低;耐镍菌株H4K5R中,金属硫蛋白基因Cup1表达量上调7.4倍,Crs5表达量显著下调2.56倍,Sod1表达量不显著上调,转录因子Cup2表达量上调3.81倍,并且表达水平均显著高于镍处理后的BY4741.本研究表明突变菌株H4K5R具有较强的镍耐受性;镍胁迫下,突变菌株中金属硫蛋白Cup1与转录因子Cup2的表达变化趋势与BY4741相反,说明组蛋白H4K5的去乙酰化可能通过改变基因表达模式,从而在酿酒酵母响应镍胁迫时发挥重要的调控作用.Metallothioneins(MTs)have a function in heavy metal detoxification.One of the known epigenetic factors is histone acetylation/deacetylation,which plays an important role in gene expression regulation.However,it remains unclear whether the expression of MTs in eukaryotes is regulated by histone acetylation/deacetylation under nickel stress.In this study,Saccharomyces cerevisiae mutant H4K5R(the strain mimics the state of histone H4 lysine 5 deacetylation)was used as the experimental model.The death rate of cells under different concentrations of nickel chloride was detected using flow cytometry.We found that the growth and viability of the mutant strain were higher than those of the wild type strain under a high concentration of nickel chloride.The changes in the transcriptional levels of MTs in H4K5-deacetylation S.cerevisiae strain under nickel stress were examined.The levels of expression of MT genes,Cup1,Crs5,Sod1,and Cup2 transcription factors were quantified using qRT-PCR in the cells grown with 5 mmol/L nickel chloride.The results showed that the expression level of genes in wild-type strains was significantly reduced after nickel chloride treatment,but in the resistant strain H4K5R,the expression of MT gene Cup1 was up-regulated by 7.4 fold,the expression of Crs5 was down-regulated by 2.56 fold,the expression of Sod1 was not significantly up-regulated,and the expression of transcription factor Cup2 was up-regulated by 3.81 fold,after nickel chloride treatment.Furthermore,the expression levels of these genes in H4K5R were significantly higher than those in the wild type after nickel chloride treatment.Thus,the following conclusions were reached:a)the mutant H4K5R has strong Ni2+tolerance,and there is significant difference in the extent of suppression between the wild type and the mutant strains upon treatment with 5 mmol/L nickel chloride;b)the changing trends of MT genes,Cup1 and Cup2,of H4K5R were opposite to that of BY4741,which indicates that the deacetylation of histone H4K5 regulates the expression p

关 键 词：金属硫蛋白 组蛋白乙酰化 表观遗传 镍胁迫 

分 类 号：X17[环境科学与工程—环境科学]