MBD4-mediated glycosylase activity on a chromatin template is enhanced by acetylation
MBD4-mediated glycosylase activity on a chromatin template is enhanced by acetylation
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DOI：
10.1128/mcb.00588-08
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发表时间：
2008-08-01
影响因子：
5.3
通讯作者：
Ausio, Juan
中科院分区：
文献类型：
--
作者：
Ishlbashi, Toyotaka;So, Kevin;Ausio, Juan
MBD 4糖基化酶从DNA切除错配碱基的能力已经在体外使用具有不同程度的胞嘧啶甲基化的DNA底物，在存在或不存在重构核小体的情况下进行了评估。尽管MBD 4结合甲基化胞嘧啶的能力增强，但其糖基化酶活性对T/G错配的效率略微依赖于DNA底物的甲基化程度。由竞争者DNA引起的活性降低同样不受底物或竞争者的甲基化状态的影响。我们的研究结果还表明，MBD 4有效地处理核小体内的T/G错配。此外，糖酵解酶的活性不受核小体内的错配的定位。然而，组蛋白超乙酰化促进了从核小体模板中切除碱基的效率，而不管错配相对于核小体对称性的假二分体轴的位置如何。
The ability of the MBD4 glycosylase to excise a mismatched base from DNA has been assessed in vitro using DNA substrates with different extents of cytosine methylation, in the presence or absence of reconstituted nucleosomes. Despite the enhanced ability of MBD4 to bind to methylated cytosines, the efficiency of its glycosylase activity on T/G mismatches was slightly dependent on the extent of methylation of the DNA substrate. The reduction in activity caused by competitor DNA was likewise unaffected by the methylation status of the substrate or the competitor. Our results also show that MBD4 efficiently processed T/G mismatches within the nucleosome. Furthermore, the glycolytic activity of the enzyme was not affected by the positioning of the mismatch within the nucleosome. However, histone hyperacetylation facilitated the efficiency with which the bases were excised from the nucleosome templates, irrespective of the position of the mismatch relative to the pseudodyad axis of symmetry of the nucleosome.