摘要
Trichostatin A(TSA)是一种特异的组蛋白去乙酰化酶抑制剂。研究显示,TSA可以特异地抑制组蛋白去乙酰化酶活性,提高细胞的组蛋白乙酰化水平,激活基因的表达。但是,目前还不是很清楚TSA处理是否对组蛋白甲基化产生影响。本研究以成纤维细胞为研究对象,利用免疫细胞化学技术及激光共聚焦显微镜,探讨了TSA处理体细胞对其组蛋白乙酰化及甲基化修饰的影响。结果显示,随TSA浓度增加,体细胞形态发生明显的改变,细胞变得扁平且核区较大,处理后组蛋白H4K8位点的乙酰化水平随着TSA浓度的增加明显提高。检测组蛋白H3上两个甲基化位点发现,随组蛋白乙酰化水平的增加,H3K4位点的三甲基化(H3K4me3)水平也显著提高。但是,对于H3K9的二甲基化水平(H3K9me2)则没有明显变化。以上结果显示,TSA的处理不仅可以提高体细胞的组蛋白乙酰化水平,同时也增加了与基因表达激活相关组蛋白修饰位点的甲基化水平,但是对于与沉默基因相关的组蛋白修饰位点则没有明显的影响。
Trichostatin A, a histone deacetylase inhibitor, could increase histone acetylation, and active gene expression in somatic cells. However, effect of TSA on histone methylation is unclear. In present study, the bovine fibroblast cells were treated with TSA, and histone acetylation and methylation were examined by using indirect immunofluorescence and scanning confocal microscopy. We found that the morphology of cells was changed from being slightly concave to more fiat and elongated even at the 10ng/mL group. Intensive H4K8ac signals in fibroblast cells were observed after TSA treatment. A similar increasing with H4K8ac in H3K4me3 was found, but no change was observed at H3K9me2 when somatic cells were treated with TSA. These result indicated that TSA was not only increasing histone acetylation, but also increasing histone methylation that was correlated with gene expression. However, TSA could not change the level of histone methylation that regulated gene silence.
基金
教育部博士点基金项目(20050126005)
内蒙古自然科学基金重点项目(200508010403)
