Transcription factors Sp1 and Sp3 regulate basal transcription of the human IRF-3 gene

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• 作者：Hua-Guo Xu^a ; ^b ; ¹ ; Rui Jin^a ; ¹ ; Wei Ren^a ; Li Zou^a ; Yi Wang^a ; Guo-Ping Zhou^a ; ^{gpzhou2003@126.com}
• 关键词：Interferon regulatory factor 3 (IRF-3) ; Transcriptional activity ; Promoter ; Sp1 ; Sp3
• 刊名：Biochimie
• 出版年：2012
• 期刊代码：24_03009084
• 类别：bio
• 出版时间：June, 2012
• 卷：94
• 期：6
• 页码：1390-1397
• 文件大小：772 K

摘要

Interferon regulatory factor 3 (IRF-3) plays a crucial role in initiation and development of the IFN antiviral response. The expression level of human IRF-3 is thought to be closely related to antiviral state of cells. However, the mechanisms of the transcription regulation of IRF-3 have remained largely unknown. We previously reported that transcription factor E2F1 negatively regulates the basal transcriptional activity of IRF-3. Here we demonstrate that transcription factors Sp1 and Sp3 up-regulate the basal transcriptional activity of IRF-3 and increase IRF-3 expression at mRNA level. By transient transfection analysis we revealed that mutation of Sp1/NRF-1 binding site resulted in a profound reduction of IRF-3 promoter activity. Overexpression of Sp1 and Sp3, but not NRF-1, transactivated the IRF-3 promoter activity in reporter gene assays while knocking-down of endogenous Sp1 and Sp3 by a shRNA strategy markedly inhibited IRF-3 promoter activity. Chromatin immunoprecipitation (ChIP) assays showed that Sp1 and Sp3 interact with the IRF-3 promoter in聽vivo. These results suggest that basal expression level of IRF-3 is regulated by transcription factors Sp1 and Sp3.