几种细胞因子对小鼠核糖体蛋白L6表达的调控

Regulation of Ribosomal Protein RpL6 Expression by Erythropoietin, α-Interferon and γ-Interferon

小鼠的核糖体蛋白RpL6启动子除了具有看家基因启动子的特点外 ,还含有多种转录因子的识别位点 .如GATA序列 1,γ干扰素核心序列 ,α干扰素应答序列 2等 ,提示RpL6的表达可为细胞外因子所诱导 .为了证实这一点 ,分别用促红细胞生成素、γ干扰素和α干扰素处理K5 6 2和Jurkat细胞 ,并用RNA印迹和荧光素酶报告试验检测了RpL6的mRNA水平和启动子活性 .RNA印迹结果显示 ,在上述细胞因子作用下 ,RpL6的mRNA水平均有所提高 .利用荧光素酶报告系统 ,用含有不同细胞因子识别位点启动子序列的报告质粒转染Jurkat和K5 6 2细胞 ,比较了启动子在细胞因子诱导前后的转录激活活性 .结果显示 ,细胞因子诱导后启动子活性明显升高 ,且与应答序列的存在与否有直接关系 .这些结果表明 ,细胞因子对RpL6转录的提高 ,是通过作用于启动子上相应的识别位点提高启动子活性而实现的 .

Mouse ribosomal protein (Rp) L6 promoter contains several transcription binding sites, in addition to common features shared by other Rp promoters, suggesting that RpL6 promoter might be induced by some extracellular elements. To access this question, Jurkat and K562 cells were cultured with α IFN, γ IFN or EPO and looked at RpL6 expression by Northern hybridization as well as reporter assay. Treatment with these cytokines upregulated RpL6 mRNA was detected by Northern hybridization. Reporter vectors with promoter fragments containing different transcription factor binding sites were constructed and transiently transfected to Jurkat and K562 cells cultured with α IFN, γ IFN or EPO. Luciferase activity was examined in the cell lysates. The promoter activity of RpL6 was elevated significantly after cytokine treatment. These results suggest that cytokines may increase the transcription level of RpL6 gene via induction of the RpL6 promoter.