Epigenetic modification,including histone modification,precisely controls target gene expression.The posttranscriptional regulation of the innate signaling-triggered production of inflammatory cytokines and type I int...Epigenetic modification,including histone modification,precisely controls target gene expression.The posttranscriptional regulation of the innate signaling-triggered production of inflammatory cytokines and type I interferons has been fully elucidated,whereas the roles of histone modification alteration and epigenetic modifiers in regulating inflammatory responses need to be further explored.Di/tri-methylation modifications of histone 3 lysine 79(H3K79me2/3)have been shown to be associated with gene transcriptional activation.Disruptor of telomeric silencing-1-like(Dot1l)is the only known exclusive H3K79 methyltransferase and regulates the proliferation and differentiation of tumor cells.However,the roles of Dot1l and Dot1l-mediated H3K79 methylation in innate immunity and inflammatory responses remain unclear.Here,we found that H3K79me2/3 modification levels at the Il6 and Ifnb1 promoters,as well as H3K79me2 modification at the Tnfαpromoter,were increased in macrophages activated by Toll-like receptor(TLR)ligands or virus infection.The innate signals upregulated Dot1l expression in macrophages and THP1 cells.Dot1l silencing or a Dot1l inhibitor preferentially suppressed the production of IL-6 and interferon(IFN)-βbut not of TNFαin macrophages and THP1 cells triggered by TLR ligands or virus infection.Dot1l was recruited to the proximal promoter of the Il6 and Ifnb1 but not Tnfαgene and then mediated H3K79me2/3 modification at the Il6 and Ifnb1 promoters,consequently facilitating the transcription and expression of Il6 and Ifnb1.Thus,Dot1l-mediated selective H3K79me2/3 modifications at the Il6 and Ifnb1 promoters are required for the full activation of innate immune responses.This finding adds new insights into the epigenetic regulation of inflammatory responses and pathogenesis of autoimmune diseases.展开更多
Dot1(disruptor of telomeric silencing 1)最初在芽殖酵母中通过遗传筛选基因被发现,缺失则会引起端粒沉默。Dot1和其脊椎动物同源物DOT1L(Dot1-like)都具有催化组蛋白H3第79位赖氨酸(H3K79)甲基化的组蛋白甲基转移酶活性。在人类各种...Dot1(disruptor of telomeric silencing 1)最初在芽殖酵母中通过遗传筛选基因被发现,缺失则会引起端粒沉默。Dot1和其脊椎动物同源物DOT1L(Dot1-like)都具有催化组蛋白H3第79位赖氨酸(H3K79)甲基化的组蛋白甲基转移酶活性。在人类各种组织中,DOT1L基因启动子区域的CpG岛均呈现极低的DNA甲基化水平,说明DOT1L基因在人体中广泛中等程度表达。DOT1L基因在EBV转化的细胞及睾丸中表达水平升高。Dot1/DOT1L介导的H3K79甲基化参与多种生物学过程,并在小鼠基因损伤实验中发现DOT1L在心功能、红细胞生成、白血病及多种肿瘤的疾病发展中起重要的作用,因而DOT1L已成为针对表观遗传修饰因子的重要药物靶点。本文对Dot1/DOT1L在生理和病理方面的研究进展作一综述。展开更多
基金This work was supported by the National Natural Science Foundation of China(81788101,31570871,31770970)CAMS Innovation Fund for Medical Sciences(2016-12M-1-003)the National Key Basic Research Program of China(2015CB964403).
文摘Epigenetic modification,including histone modification,precisely controls target gene expression.The posttranscriptional regulation of the innate signaling-triggered production of inflammatory cytokines and type I interferons has been fully elucidated,whereas the roles of histone modification alteration and epigenetic modifiers in regulating inflammatory responses need to be further explored.Di/tri-methylation modifications of histone 3 lysine 79(H3K79me2/3)have been shown to be associated with gene transcriptional activation.Disruptor of telomeric silencing-1-like(Dot1l)is the only known exclusive H3K79 methyltransferase and regulates the proliferation and differentiation of tumor cells.However,the roles of Dot1l and Dot1l-mediated H3K79 methylation in innate immunity and inflammatory responses remain unclear.Here,we found that H3K79me2/3 modification levels at the Il6 and Ifnb1 promoters,as well as H3K79me2 modification at the Tnfαpromoter,were increased in macrophages activated by Toll-like receptor(TLR)ligands or virus infection.The innate signals upregulated Dot1l expression in macrophages and THP1 cells.Dot1l silencing or a Dot1l inhibitor preferentially suppressed the production of IL-6 and interferon(IFN)-βbut not of TNFαin macrophages and THP1 cells triggered by TLR ligands or virus infection.Dot1l was recruited to the proximal promoter of the Il6 and Ifnb1 but not Tnfαgene and then mediated H3K79me2/3 modification at the Il6 and Ifnb1 promoters,consequently facilitating the transcription and expression of Il6 and Ifnb1.Thus,Dot1l-mediated selective H3K79me2/3 modifications at the Il6 and Ifnb1 promoters are required for the full activation of innate immune responses.This finding adds new insights into the epigenetic regulation of inflammatory responses and pathogenesis of autoimmune diseases.
文摘Dot1(disruptor of telomeric silencing 1)最初在芽殖酵母中通过遗传筛选基因被发现,缺失则会引起端粒沉默。Dot1和其脊椎动物同源物DOT1L(Dot1-like)都具有催化组蛋白H3第79位赖氨酸(H3K79)甲基化的组蛋白甲基转移酶活性。在人类各种组织中,DOT1L基因启动子区域的CpG岛均呈现极低的DNA甲基化水平,说明DOT1L基因在人体中广泛中等程度表达。DOT1L基因在EBV转化的细胞及睾丸中表达水平升高。Dot1/DOT1L介导的H3K79甲基化参与多种生物学过程,并在小鼠基因损伤实验中发现DOT1L在心功能、红细胞生成、白血病及多种肿瘤的疾病发展中起重要的作用,因而DOT1L已成为针对表观遗传修饰因子的重要药物靶点。本文对Dot1/DOT1L在生理和病理方面的研究进展作一综述。
