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[摘要]
目的 基于定量蛋白组学分析和分子生物学实验验证,阐明人参皂苷Rd调控组蛋白H3乙酰化水平的作用机制。方法 利用氨基酸稳定同位素标记(SILAC)技术和液相色谱-质谱联用技术(LC-MS/MS)检测人参皂苷Rd作用下人胚肾HEK293T细胞蛋白质组的动态变化;通过对定量蛋白组学数据库分析监测组蛋白乙酰转移酶(HATs)和组蛋白去乙酰转移酶(HDACs)表达水平的变化,并通过Western blotting和实时荧光定量PCR(qRT-PCR)实验验证相关蛋白质表达和转录水平的变化;利用siRNA进行基因敲除实验以明确人参皂苷Rd对组蛋白H3K9和H3K18位点乙酰基修饰水平的调控作用。结果 人参皂苷Rd处理HEK293T细胞后,组蛋白H3K9ac、H3K18ac表达水平降低,但催化修饰这2个位点的P300没有明显变化;同时人参皂苷Rd可上调HDAC2的转录和表达水平,siHDAC2处理HEK293T细胞后,逆转了人参皂苷Rd对H3K9ac、H3K18ac的下调作用。结论 人参皂苷Rd通过上调HDAC2,下调组蛋白H3K9和H3K18位赖氨酸位点的乙酰化水平,从而影响下游基因的转录激活。
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[Abstract]
Objective Based on quantitative proteomics analysis and molecular biology experimental verification, the regulatory mechanism of ginsenoside Rd on histone H3 acetylation levels was elucidated. Methods The effects of ginsenoside Rd on the dynamic changes of proteome of HEK293T cells were detected by.stable isotope labeling with amino acid (SILAC) technique and LC-MS/MS; Quantitative proteomics database analysis was used to monitor the changes in histone acetyltransferase HATs and histone deacetylase HDACs expression levels. Western blotting and qRT-PCR were used to verify the changes of related protein expression and transcriptional level. Gene knockdown experiments were performed using siRNAs to determine the role of ginsenoside Rd in regulating the level of acetyl modifications at histone H3K9 and K18 sites. Results The histone H3K9ac, H3K18ac expression levels in HEK293T cells decreased after ginsenoside Rd treatment, but the P300 catalytic modification of these two sites did not change significantly; At the same time, ginsenoside Rd up-regulated the transcription and expression of HDAC2, and siHDAC2 treatment reversed the down-regulation effects of ginsenoside Rd on H3K9ac and H3K18ac in HEK293T cells. Conclusion Ginsenoside Rd down-regulates the acetylation level of lysine at histone H3K9 and K18 sites by up-regulating HDAC2, thereby affecting transcriptional activation of downstream genes.
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[基金项目]
吉林省重大科技攻关项目(20160201001YY);吉林省科技厅重点科技成果转化项目(20170307031YY);吉林省科技厅优秀青年人才基金项目(20180520050JH)