Microbiological Research Group, National Center for Epidemiology, Pihenő út 1, H-1529 Budapest, Hungary.
Biochem Biophys Res Commun. 2013 May 24;435(1):8-15. doi: 10.1016/j.bbrc.2013.03.127. Epub 2013 Apr 10.
We analyzed epigenetic marks at the CD23 regulatory regions in well characterized Epstein-Barr virus (EBV)-carrying cell lines covering the major latency types. Bisulfite sequencing showed that DNA methylation is not a major regulator of EBV-induced CD23 transcription, although a wide hypomethylated DNA sequence in the regulatory regions is always present in the cell lines with high CD23 expression. Acetylated histone H3 levels at the CD23b promoter showed strong correlation with CD23b expression, while a weaker correlation could be observed at the CD23a core promoter. DMS in vivo footprinting at the intronic EBV-responsive enhancer and the intermediate-affinity CBF1 site at the CD23a core promoter did not reveal any significant sign of in vivo protein-DNA interactions, despite the presence of strong, characteristic footprints in the same DMS-treated DNA samples at the two CBF1 sites of the LMP2A-promoter. Our in vivo results suggest a minor role for DNA methylation, while a more important role for histone acetylation in the regulation of EBV-induced CD23 expression. Furthermore, our in vivo footprinting results support the complex model of CD23 induction by EBV, rather than a simple model with direct transactivation of CD23 by EBNA-2.
我们分析了在涵盖主要潜伏期类型的经过充分特征描述的 Epstein-Barr 病毒（EBV）携带细胞系中 CD23 调控区的表观遗传标记。亚硫酸氢盐测序显示，DNA 甲基化并不是 EBV 诱导 CD23 转录的主要调控因素，尽管在高 CD23 表达的细胞系中，调控区总是存在广泛的低甲基化 DNA 序列。CD23b 启动子处乙酰化组蛋白 H3 水平与 CD23b 表达呈强相关性，而在 CD23a 核心启动子处则可观察到较弱的相关性。在 CD23a 核心启动子的内含子 EBV 反应增强子和中亲和力 CBF1 位点的体内 DMS 足迹分析并未揭示任何体内蛋白质-DNA 相互作用的明显迹象，尽管在同一 DMS 处理的 DNA 样本中，在 LMP2A 启动子的两个 CBF1 位点存在强烈的特征性足迹。我们的体内结果表明，DNA 甲基化的作用较小，而组蛋白乙酰化在 EBV 诱导的 CD23 表达调控中起着更为重要的作用。此外，我们的体内足迹分析结果支持 EBV 诱导 CD23 表达的复杂模型，而不是 EBNA-2 直接转录激活 CD23 的简单模型。
