Human Cytomegalovirus pUL83 Stimulates Activity of the Viral Immediate-Early Promoter through Its Interaction with the Cellular IFI16 Protein
Human Cytomegalovirus pUL83 Stimulates Activity of the Viral Immediate-Early Promoter through Its Interaction with the Cellular IFI16 Protein
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DOI：
10.1128/jvi.00139-10
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发表时间：
2010-08-01
影响因子：
5.4
通讯作者：
Shenk, Thomas
中科院分区：
文献类型：
--
作者：
Cristea, Ileana M.;Moorman, Nathaniel J.;Shenk, Thomas
人巨细胞病毒（HCMV）病毒体蛋白pUL83（也称为pp65）抑制干扰素诱导的细胞基因的表达。在这项工作中，我们证明，pUL83也是重要的有效诱导转录从病毒的主要立即早期启动子。感染突变体病毒在UL83开放阅读框（ORF）（UL83Stop）中含有提前翻译终止密码子，导致主要立即早期启动子的转录以时间和多样性依赖的方式减少。在报道基因测定中，pUL83单独表达能够反式激活启动子，并且pUL83与感染细胞中的启动子缔合。为了研究蛋白质调节主要立即早期启动子的机制，我们利用突变病毒从其自身的启动子表达表位标记的pUL83，以确定感染过程中pUL83的蛋白质结合伴侣。我们鉴定并证实了在HCMV感染的整个过程中pUL83与细胞IFI16家族成员的相互作用。pUL83将IFI16募集到主要的立即早期启动子，并且IFI16在启动子处的结合依赖于pUL83的存在。与用UL83Stop病毒获得的结果一致，用野生型病毒感染IFI16敲低细胞导致与对照细胞相比立即早期转录物水平降低。这些数据确定了pUL83在启动人巨细胞病毒基因表达级联反应中的一个以前未知的作用。
The human cytomegalovirus (HCMV) virion protein pUL83 (also termed pp65) inhibits the expression of interferon-inducible cellular genes. In this work we demonstrate that pUL83 is also important for efficient induction of transcription from the viral major immediate-early promoter. Infection with a mutant virus containing a premature translation termination codon in the UL83 open reading frame (ORF) (UL83Stop) resulted in decreased transcription from the major immediate-early promoter in a time- and multiplicity-dependent manner. Expression of pUL83 alone is capable of transactivating the promoter in a reporter assay, and pUL83 associates with the promoter in infected cells. To investigate the mechanism by which the protein regulates the major immediate-early promoter, we utilized a mutant virus expressing an epitope-tagged pUL83 from its own promoter to identify protein binding partners for pUL83 during infection. We identified and confirmed the interaction of pUL83 with cellular IFI16 family members throughout the course of HCMV infection. pUL83 recruits IFI16 to the major immediate-early promoter, and IFI16 binding at the promoter is dependent upon the presence of pUL83. Consistent with the results obtained with the UL83Stop virus, infection of IFI16 knockdown cells with wild-type virus resulted in decreased levels of immediate-early transcripts compared to those of control cells. These data identify a previously unknown role for pUL83 in the initiation of the human cytomegalovirus gene expression cascade.