TOPO Ⅱα启动子调控因子组蛋白甲基化修饰在苯中毒致造血毒性中的作用

Histone methylation modification of topoisomerase IⅡα promoter regulation factors in patients with chronic benzene poisoning

目的:研究拓扑异构酶(TOPO)Ⅱα启动子调控因子(SP1、ATF-2、SP3、NF-YA、NF-M、P53、CMYB、C-JUN、ICBP90)组蛋白甲基化修饰在苯中毒致造血毒性中的作用。方法:25例临床慢性苯中毒患者骨髓单个核细胞为病例组,25例正常人骨髓单个核细胞为对照组,染色质免疫沉淀分析(Ch IP)技术探讨TOPOⅡα启动子各调控因子组蛋白甲基化水平的变化,RT-PCR法测定TOPO Ⅱα启动子各调控因子m RNA表达水平的改变。结果:1与对照组比较,病例组TOPO Ⅱα启动子调控因子NF-M、C-JUN组蛋白H3K4甲基化水平下降,差异有统计学意义(P<0.05),SP1、ATF-2、SP3、NF-YA、P53、C-MYB、ICBP90组蛋白H3K4甲基化水平无明显改变(P>0.05);SP1、NF-M组蛋白H3K9甲基化水平升高,差异有统计学意义(P<0.05或P<0.01),而ATF-2、SP3、NF-YA、P53、C-MYB、C-JUN、ICBP90组蛋白H3K9甲基化水平无明显改变(P>0.05)。2与对照组比较,病例组TOPO Ⅱα启动子调控因子SP1、NF-YA、C-MYB、NF-M及C-JUN m RNA表达水平降低,差异有统计学意义(P<0.05或P<0.01),ATF-2、ICBP90 m RNA表达水平不变(P>0.05),SP3、P53 m RNA表达水平则升高(P<0.05或P<0.01)。结论:1慢性苯中毒TOPO Ⅱα启动子调控因子组蛋白化学修饰水平的改变伴随着调控因子m RNA水平的变化。2TOPO Ⅱα启动子调控因子组蛋白甲基化修饰在苯中毒所致的造血毒性中发挥一定的作用。

Objective： To investigate histone methylation modification of topoisomerase Ⅱα（TOPO Ⅱα） promoter regulation factors in patients with chronic benzene poisoning, to explore the possible regulatory mechanism of TOPO Ⅱα involved in toxicity of chronic benzene poisoning. Methods： The bone marrow samples were cellected from 25 chronic benzene poisoning cases and 25 normal controls. The Chromatin Immunoprecipitation（Ch IP） assay was carried out to study the possible mechanism of TOPO Ⅱα promoter regulation factors expression changes.TOPO Ⅱα promoter regulation factors m RNA were detected by RT-PCR technique. Results： Compared with the normal controls, the histone H3K4 methylation level of TOPO Ⅱα promoter regulation factors NF-M, C-JUN in chronic benzene poisoning patients decreased（P〈0.05）, while the histone H3K4 methylation level of SP1, ATF-2, SP3, NF-YA, P53, C-MYB, ICBP90 without obvious change（P〉0.05）. The histone H3K9 methylation level of SP1, NF-M increased（P〈0.05 or P〈0.01）, while the histone H3K9 methylation level of ATF-2, SP3, NF-YA, P53, C-MYB, C-JUN, ICBP90 was no significant change（P〉0.05）. The m RNA expression of TOPO Ⅱα promoter regulation factors SP1, NF-YA, C-MYB, NF-M and C-JUN were significantly lower than that in the control（P〈0.05 or P〈0.01）, while the expression of SP3, P53 m RNA increased（P〈0.05 or P〈0.01）, ATF-2, ICBP90 m RNA wasn＇t changed（P〉0.05）. Conclusion： In chronic benzene poisoning patients, TOPO Ⅱα promoter regulation factors histone modification changes accompanied with m RNA level changed. Histone methylation modification of topoisomerase enzyme Ⅱα promoter regulation factors play an important role in the benzene＇s hematopoietic toxicities.