Transcriptional Activation of the HCMV Genome

Cells infected by with the human cytomegalovirus (HCMV) have two potential fates once the HCMV genome enters the nucleus. In an active infection there is extensive viral gene expression, viral DNA replication and release of progeny virus. In contrast, in a latent infection the lytic transcription programme of HCMV is effectively suppressed and the cells undergo latent infection. The suppression of viral lytic gene expression observed during latency is the result from the cells inability to support robust viral immediate early (IE) gene expression; crucial genes responsible for driving the lytic cycle. The repression of IE gene expression results from specific post-translational modifications of histones associated with the viral major immediate early promoter (MIEP). The histone modifications present on the MIEP impart a repressive chromatin structure preventing transcriptional activity.

感染人类巨细胞病毒（HCMV）的细胞，在HCMV基因组进入细胞核后，将面临两种潜在命运。在活跃感染阶段，病毒基因表达广泛，病毒DNA复制以及子代病毒的释放均得以进行。相反，在潜伏感染阶段，HCMV的裂解性转录程序被有效抑制，细胞进入潜伏感染状态。潜伏期间观察到的病毒裂解基因表达的抑制，源于细胞无法支持强有力的病毒即刻早期（IE）基因表达，而这些即刻早期基因是驱动裂解周期的重要基因。即刻早期基因表达的抑制，源于与病毒主要即刻早期启动子（MIEP）相关的组蛋白的特定翻译后修饰。存在于MIEP上的组蛋白修饰赋予了抑制性的染色质结构，从而阻止转录活性。