Human cytomegalovirus infection induces cellular thymidylate synthase gene expression in quiescent fibroblasts
Human cytomegalovirus infection induces cellular thymidylate synthase gene expression in quiescent fibroblasts
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DOI：
10.1099/0022-1317-83-12-2983
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发表时间：
2002-12-01
影响因子：
3.8
通讯作者：
Landolfo, S
中科院分区：
文献类型：
--
作者：
Gribaudo, G;Riera, L;Landolfo, S
巨细胞病毒（CMV）对非增殖细胞的生产性感染需要宿主生物化学途径的协调刺激，使细胞合成DNA。在这里，我们说明了人类巨细胞病毒（HCMV）刺激细胞胸苷酸合成酶（TS）基因在静止的人胚肺成纤维细胞表达的能力。TS mRNA和蛋白水平在静止细胞中几乎检测不到，但在HCMV感染后大大增加。TS活性的抑制显示出损害HCMV DNA合成，表明TS上调是静止细胞中有效HCMV复制所需的。TS基因表达的增加是由于基因转录的增加，因为由人TS启动子驱动的报告基因的表达被HCMV感染强烈诱导。人TS启动子的缺失分析确定了两个积极的因素，这是重要的增加转录。我们以前已经表明，鼠CMV（MCMV）刺激小鼠TS启动子的机制，取决于在启动子区的E2F元件的存在。然而，在人TS启动子中两个潜在的E2F结合位点的缺失并不能阻止病毒诱导的TS启动子活性的增加。我们的数据表明，HCMV激活人类TS基因转录的机制是独立的E2F和不同的MCMV刺激小鼠TS启动子。
Productive infection of non-proliferating cells by cytomegalovirus (CMV) requires the coordinated stimulation of host biochemical pathways that prepare cells to synthesize DNA. Here we illustrate the ability of human CMV (HCMV) to stimulate cellular thymidylate synthase (TS) gene expression in quiescent human embryonic lung fibroblasts. TS mRNA and protein levels are nearly undetectable in quiescent cells, but are greatly increased following HCMV infection. Inhibition of TS activity was shown to impair HCMV DNA synthesis, demonstrating that TS upregulation is required for efficient HCMV replication in quiescent cells. The increase in TS gene expression was due to an increase in gene transcription, since the expression of a reporter gene driven by the human TS promoter was strongly induced by HCMV infection. Deletion analysis of the human TS promoter identified two positive elements that are important for this increased transcription. We have previously shown that murine CMV (MCMV) stimulates the mouse TS promoter by a mechanism that depends on the presence of an E2F element in the promoter region. However, deletion of the two potential E2F binding sites in the human TS promoter did not prevent the virus-induced increase in TS promoter activity. Our data suggest that HCMV activates human TS gene transcription by mechanisms that are independent of E2F and different from those used by MCMV to stimulate the mouse TS promoter.