Department of Life Science, Dongguk University-Seoul, Seoul, South Korea.
Intervirology. 2013;56(2):91-103. doi: 10.1159/000343749. Epub 2013 Jan 9.
Histone H3 lysine 4 is trimethylated by the human Set1 complex, which regulates the activation of gene expression. The aim of this study was to identify whether the levels of histone H3 lysine 4 trimethylation (H3K4me3) and the recruitment of human Set1 complex at the promoter regions of lytic genes quantitatively change during reactivation from latent to lytic infection of Kaposi's sarcoma-association herpesvirus (KSHV).
During KSHV reactivation, global changes of H3K4 methylation in KSHV-infected cells were analyzed by Western blot. The relative levels of association between proteins and promoter regions were determined by chromatin immunoprecipitation assay and quantitative real-time PCR using specific antibodies and primer sets.
Our results showed that KSHV reactivation does not alter the overall cellular levels of H3K4 methylation. We observed that the switch from latency to lytic cycle leads to upregulation of H3K4me3 at the active lytic genes. We also found that the recruitment of RNA pol II and subunits of human Set1 complex were enriched at the same regions in response to KSHV reactivation.
These results demonstrate that the increase of H3K4me3 by human Set1 complex is involved in activation of lytic genes during the lytic infection of KSHV.
组蛋白 H3 赖氨酸 4 被人类 Set1 复合物三甲基化，后者调节基因表达的激活。本研究旨在确定在卡波济肉瘤相关疱疹病毒（KSHV）潜伏感染向裂解感染再激活过程中，组蛋白 H3 赖氨酸 4 三甲基化（H3K4me3）水平和人 Set1 复合物在裂解基因启动子区的募集是否定量变化。
在 KSHV 再激活过程中，通过 Western blot 分析 KSHV 感染细胞中 H3K4 甲基化的全局变化。通过染色质免疫沉淀测定和使用特异性抗体和引物组的实时定量 PCR，确定蛋白与启动子区之间的相对结合水平。
我们的结果表明，KSHV 再激活不会改变细胞内 H3K4 甲基化的总体水平。我们观察到，从潜伏到裂解周期的转变导致活跃的裂解基因中 H3K4me3 的上调。我们还发现，RNA pol II 和人 Set1 复合物亚基在响应 KSHV 再激活时在相同区域募集增加。
这些结果表明，人类 Set1 复合物增加 H3K4me3 参与了 KSHV 裂解感染期间裂解基因的激活。
