The mechanism of genome maintenance and transcriptional regulation in latent HCMV infection

我们先前证明了含有一个GC盒的主要即刻早期(MIE)近端增强子和含有启动子的TATA盒是转录和病毒复制所需的最低限度的元件(H.Isomura等人)。J·维罗尔。78：12788,2004年)。在这里，我们报告了凝胶迁移率改变分析(EMSA)检测到Sp1和SP3转录因子与位于转录起始位点(1)约-55和-75的GC盒上的结合。报告基因实验表明，两个Sp1/Sp3结合位点对HCMV mie启动子均有正向协同作用。感染后Sp1水平升高，而Sp3水平不变。Sp1/Sp3结合位点突变的重组病毒的MIE转录或病毒复制几乎没有变化。相反，两个Sp1/Sp3结合位点的突变导致MIE转录和病毒复制效率低下。这些数据表明，Sp1/3结合位点在HCMV复制中具有重要作用。

We previous demonstrated that the major immediate early (MIE) proximal enhancer containing one GC box and the TATA box containing promoter are minimal elements required for transcription and viral replication (H.Isomura et al. J.Virol. 78:12788, 2004). Here we report that Electrophoretic mobility shift assays (EMSAs) detected binding of Sp1 and Sp3 transcription factors to the GC boxes located at approximately-55 and -75 relative to the transcription start site (+1). Reporter gene experiments showed that both of the Sp1/Sp3 binding sites have a positive and synergistic effect on the HCMV MIE promoter. After infection, the level of Sp1 increased while Sp3 remain constant. There was little to no change in MIE transcription or viral replication for recombinant viruses with one or the other Sp1/Sp3 binding site mutated. In contrast, mutation of both Sp1/Sp3 binding sites caused inefficient MIE transcription and viral replication. These data indicate that the Sp1/3 binding sites have a significant role in HCMV replication.