摘要
Virus infection induces the production of type I interferons （IFNs）. IFNs bind to their heterodimeric receptors to initiate downstream cascade of signaling, leading to the up-regulation of interferon-stimulated genes （ISGs）. ISGs play very important roles in innate immunity through a variety of mechanisms. Although hundreds of ISGs have been identified, it is commonly recognized that more ISGs await to be discovered. The aim of this study was to identify new ISGs and to probe their roles in regulating virus-induced type I IFN production. We used consensus interferon （Con-IFN）, an artificial alpha IFN that was shown to be more potent than naturally existing type I IFN, to treat three human immune cell lines, CEM, U937 and Daudi cells. Microarray analysis was employed to identify those genes whose expres- sions were up-regulated. Six hundred and seventeen genes were up-regulated more than 3-fold. Out of these 617 genes, 138 were not previously reported as ISGs and thus were further pursued. Validation of these 138 genes using quantitative reverse transcription PCR （qRT-PCR） confirmed 91 genes. We screened 89 genes for those involved in Sendal virus （SeV）-induced IFN-13 promoter activation, and PIM1 was identified as one whose expression inhibited SeV-mediated IFN-β activation. We provide evidence indicating that PIM1 specifically inhibits RIG-I- and MDA5-mediated IFN-β signaling. Our results expand the ISG library and iden- tify PIM1 as an ISG that participates in the regulation of virus-induced type I interferon production.
Virus infection induces the production of type I interferons （IFNs）. IFNs bind to their heterodimeric receptors to initiate downstream cascade of signaling, leading to the up-regulation of interferon-stimulated genes （ISGs）. ISGs play very important roles in innate immunity through a variety of mechanisms. Although hundreds of ISGs have been identified, it is commonly recognized that more ISGs await to be discovered. The aim of this study was to identify new ISGs and to probe their roles in regulating virus-induced type I IFN production. We used consensus interferon （Con-IFN）, an artificial alpha IFN that was shown to be more potent than naturally existing type I IFN, to treat three human immune cell lines, CEM, U937 and Daudi cells. Microarray analysis was employed to identify those genes whose expres- sions were up-regulated. Six hundred and seventeen genes were up-regulated more than 3-fold. Out of these 617 genes, 138 were not previously reported as ISGs and thus were further pursued. Validation of these 138 genes using quantitative reverse transcription PCR （qRT-PCR） confirmed 91 genes. We screened 89 genes for those involved in Sendal virus （SeV）-induced IFN-13 promoter activation, and PIM1 was identified as one whose expression inhibited SeV-mediated IFN-β activation. We provide evidence indicating that PIM1 specifically inhibits RIG-I- and MDA5-mediated IFN-β signaling. Our results expand the ISG library and iden- tify PIM1 as an ISG that participates in the regulation of virus-induced type I interferon production.
基金
We thank Dr. Hongbing Shu for providing IFN-β-1uc reporter, pTK- renilla, Flag-tagged RIG-I, MDA5, VISA, TBK1 and IKKE vectors, Dr. Zhengfan Jiang for Sendai virus （SeV）. We thank Zhimin Wang, Xudong Zhao and Xiaofei Guo of the core facility of the Institute of Biophysics, CAS, for technical assistance. This work was supported by grants to Guangxia Gao from Chinese Academy of Sciences （KFZD-SW-209） and National Natural Science Foundation of China （Grant No. 81530066）.
