Zhao Zhiyuan, Tang Ka-Wei, Muylaert Isabella, Samuelsson Tore, Elias Per
From the Institute of Biomedicine, Department of Medical Biochemistry and Cell Biology, Sahlgrenska Academy, University of Gothenburg, Box 440, SE-405 30 Gothenburg, Sweden.
From the Institute of Biomedicine, Department of Medical Biochemistry and Cell Biology, Sahlgrenska Academy, University of Gothenburg, Box 440, SE-405 30 Gothenburg, Sweden
J Biol Chem. 2017 Sep 15;292(37):15489-15500. doi: 10.1074/jbc.M117.806000. Epub 2017 Jul 25.
DNA replication greatly enhances expression of the herpes simplex virus 1 (HSV-1) γ2 late genes by still unknown mechanisms. Here, we demonstrate that 5,6-dichloro-1-β-d-ribofuranosylbenzimidazole (DRB), an inhibitor of CDK9, suppresses expression of γ2 late genes with an IC of 5 μm, which is at least 10 times lower than the IC value required for inhibition of expression of early genes. The effect of DRB could not be explained by inhibition of DNA replication or loading of RNA polymerase II to late promoters and subsequent reduction of transcription. Instead, DRB reduces accumulation of γ2 late mRNA in the cytoplasm. In addition, we show that siRNA-mediated knockdown of the transcription factor SPT5, but not NELF-E, also gives rise to a specific inhibition of HSV-1 late gene expression. Finally, addition of DRB reduces co-immunoprecipitation of ICP27 using an anti-SPT5 antibody. Our results suggest that efficient expression of replication-dependent γ2 late genes is, at least in part, regulated by CDK9 dependent co- and/or post-transcriptional events involving SPT5 and ICP27.
DNA复制通过尚不清楚的机制极大地增强了单纯疱疹病毒1型（HSV-1）γ2晚期基因的表达。在此，我们证明5,6-二氯-1-β-D-呋喃核糖基苯并咪唑（DRB），一种CDK9抑制剂，以5μm的半数抑制浓度（IC）抑制γ2晚期基因的表达，这比抑制早期基因表达所需的IC值至少低10倍。DRB的作用不能通过抑制DNA复制或RNA聚合酶II加载到晚期启动子以及随后转录减少来解释。相反，DRB减少了γ2晚期mRNA在细胞质中的积累。此外，我们表明，通过小干扰RNA（siRNA）介导的转录因子SPT5而非NELF-E的敲低，也会导致对HSV-1晚期基因表达的特异性抑制。最后，添加DRB会减少使用抗SPT5抗体进行的ICP27的免疫共沉淀。我们的结果表明，依赖复制的γ2晚期基因的有效表达至少部分受涉及SPT5和ICP27的CDK9依赖性共转录和/或转录后事件调控。
