盐离子作用下组蛋白变体H2A.Z增强核小体结构的稳定性  

Histone Variant H2A.Z Enhances the Stability of Nucleosomes under the Effect of Salt Ions

作　　者：邵学勤 郭明欣 蔡禄 赵宏宇[1,2] SHAO Xue-Qin;GUO Ming-Xin;CAI Lu;ZHAO Hong-Yu(Laboratory of Functional Genome Bioinformatics,School of Life Sciences and Technology,Inner Mongolia University of Science and Technology,Baotou 014010,Inner Mongolia,China;Key Laboratory of Functional Genomics Bioinformatics of Inner Mongolia Autonomous Region,Inner Mongolia University of Science and Technology,Baotou 014010,Inner Mongolia,China)

机构地区：[1]内蒙古科技大学,生命科学与技术学院功能基因组生物信息学实验室,内蒙古包头014010 [2]内蒙古科技大学,内蒙古自治区功能基因组生物信息学重点实验室,内蒙古包头014010

出　　处：《中国生物化学与分子生物学报》2022年第3期372-380,共9页Chinese Journal of Biochemistry and Molecular Biology

基　　金：国家自然科学基金项目(No.31760247,62071259);内蒙古自然科学基金项目(No.2021MS03007)资助。

摘　　要：真核生物染色质的基本结构组成单元是核小体,基因组DNA被压缩在染色质中,核小体的存在通常会抑制转录、复制、修复和重组等发生在DNA模板上的生物学过程。组蛋白变体H2A.Z可以调控染色质结构进而影响基因的转录过程,但其详细的调控机制仍未研究清楚。为了比较含有组蛋白变体H2A.Z的核小体和常规核小体在盐离子作用下的稳定性差异,本文采用F rster共振能量转移的方法检测氯化钠、氯化钾、氯化锰、氯化钙、氯化镁等离子对核小体的解聚影响。实验对Widom 601 DNA序列进行双荧光Cy3和Cy5标记,通过荧光信号值的变化来反映核小体的解聚变化。F rster共振能量转移检测结果显示:在氯化钠、氯化钾、氯化锰、氯化钙和氯化镁作用下,含有组蛋白变体H2A.Z的核小体解聚速度相比于常规核小体要慢,且氯化钙、氯化锰和氯化镁的影响更明显。电泳分析结果表明,在75℃条件下含有组蛋白变体H2A.Z的核小体的解聚速率明显低于常规核小体。采用荧光热漂移检测(fluorescence thermal shift analysis,FTS)进一步分析含有组蛋白变体H2A.Z核小体的稳定性,发现两类核小体的荧光信号均呈现2个明显的增长期,含有组蛋白变体H2A.Z核小体的第1个荧光信号增速期所对应的温度明显高于常规核小体,表明核小体中H2A.Z/H2B二聚体的解聚变性温度要高于常规的H2A/H2B二聚体,含有组蛋白变体H2A.Z核小体的热稳定性高。研究结果均表明,含有组蛋白变体H2A.Z的核小体的结构比常规核小体的结构稳定。In eukaryotes,the basic structural unit of chromatin is the nucleosome,and genomic DNA is compressed in chromatin.The presence of nucleosomes usually inhibits the biological processes that occur on the DNA templates,such as transcription,replication,repair,and recombination,.The histone variant H2A.Z can regulate the structure of chromatin and affect the transcription process of genes,but its detailed regulation mechanism remains unclear.In this paper,the method of F rster resonance energy transfer(FRET)was used to detect the influence of sodium chloride,potassium chloride,manganese chloride,calcium chloride and magnesium chloride on the dissociation of nucleosomes.Then,the stability differences between the nucleosomes containing the histone variant H2A.Z and the conventional nucleosomes were compared under the action of salt ions.Widom 601 DNA sequence was labeled with dual fluorescence Cy3 and Cy5,and the dissociation of nucleosomes was reflected by the change of fluorescence signal value.FRET results showed that the dissociation speed of nucleosomes containing the histone variant H2A.Z under the action of sodium chloride,potassium chloride,manganese chloride,calcium chloride and magnesium chloride is slower than that of canonical nucleosomes,and the influence of calcium chloride,manganese chloride and magnesium chloride on dissociation is more obvious than sodium chloride,potassium chloride.The results of electrophoresis analysis showed that the dissociation rate of nucleosomes containing histone variant H2A.Z was significantly lower than that of canonical nucleosomes at 75℃.Fluorescence thermal shift(FTS)was used to further analyze the stability of nucleosomes containing histone variant H2A.Z.It was found that the fluorescence signals of the two types of nucleosomes showed two distinct growth periods,and the fluorescence signals generated in the dissociation process of the two types of nucleosomes showed two distinct growth periods.The temperature corresponding to the first increasing period of fluorescence

关 键 词：Forster共振能量转移 荧光热漂移 核小体解聚 组蛋白变体H2A.Z 核小体结构 

分 类 号：Q533[生物学—生物化学]