Promoter analysis of the interferon regulatory factor 2 and the SNP analysis of the gene

干扰素调节因子2(IRF-2)是一种转录调节蛋白，可抑制干扰素-α/β基因的表达。在缺乏IRF-2的小鼠身上，这种炎症性皮肤病与人类牛皮癣非常相似，会自发发展。此外，IRF-2基因位于人类染色体4q35，该基因定位于家族性银屑病易感基因座。因此，我们推测IRF-2基因可能是银屑病的候选基因。-535G&GT；A的基因分型采用NlaIII-限制性标志多态(RFLP)。凝胶移位和超移位分析用于评估转录因子的结合能力。为了证明转录活性的差异，我们进行了荧光素酶报告分析。我们在IRF-2转录启动子中发现了一个-535G&GT；A多态性。在日本，-535A等位基因在早发性(41岁以下)牛皮癣中更为常见(p=0.035)，尽管这与老发性(41岁或以上)牛皮癣无关。超平移分析发现-535G等位基因与上游刺激因子(USF)结合，而-535A等位基因不结合USF。然而，报告实验显示-535A等位基因和-535G等位基因的转录活性没有统计学差异。此外，共转染USF-1表达载体并没有刺激我们的荧光素酶报告系统的启动子活性。

Interferon regulatory factor 2 (IRF-2) is a transcriptional regulatory protein which represses the expression of interferon-alpha/beta genes. In mice lacking IRF-2, the inflammatory skin disease very similar to human psoriasis develops spontaneously. In addition, IRF-2 gene is located at human chromosome 4q35, where a familial psoriasis susceptibility locus has been mapped. Therefore, we hypothesized the IRF-2 gene is a possible candidate gene for psoriasis.Genotyping of -535G>A was performed by NlaIII-restriction flagment polymorphism (RFLP). Gel-shift and super-shift analysis were employed for the accessment of the binding abilities of transcription factors. To demonstrate differential transcriptional activities, luciferase reporter assays were perforemed.We identified a -535G>A polymorphism in the IRF-2 transcriptional promoter. The -535A allele was more frequent (p= 0.035) in early-onset (less than 41 years of age) psoriasis in Japan, although this was not associated with the old-onset (41 years or older) psoriasis. The -535G allele was found to bind upstream stimulatory factor (USF) by the supershift analysis, whereas the -535A allele did not bind USF. However, the reporter assay revealed no statistical difference of the transcriptional activity between -535A allele and -535G allele. Furthermore, co-transfection of the USF-1 expression vector did not stimulate the promoter activity of our luciferase reporter system.