含有RU486调控系统的质粒DNA介导的可诱导的IL-12基因在小鼠体内表达

目的 评价含有RU486调控系统的质粒DNA诱导目的 基因表达的能力.方法 将编码LacZ的pRS-LaeZ和编码小鼠IL-12的pRS22体外转染细胞或静脉快速注射入小鼠体内.X-gal染色检测培养细胞和组织中LacZ基因的表达.ELISA法检测培养细胞上清和血清中IL-12的表达水平.结果 加入RU486诱导后,在肝脏来源的HepG2细胞中约30%被染成蓝色;而不加RU486时,仅有不到1%的细胞蓝染.在其他非肝脏来源的细胞中,无论是否加入RU486诱导,都只有不到0.5%的细胞蓝染.转染pRS22的HepG2细胞,培养细胞上清中IL-12表达水平随RU486浓度的升高而增加.静脉注射pRS-LacZ后,用RU486诱导时,仅在肝脏组织中见到蓝染细胞.静脉注射pRS22后,血清中IL-12表达水平与质粒及RU486的剂量有关.结论 含有RU486调节系统的质粒DNA可以通过加入或取消RU486来开启或关闭IL-12基因的表达,而且可以通过改变质粒或RU486的剂量来调控IL-12基因的表达水平.

Inducible IL-12 gene expression mediated by naked DNA containing an RU486 regulatory system

Objective To evaluate the inducibility of target gene expression induced by plasmid DNA carrying a RU486 regulatory system. Methods Plasmid pRS-LacZ encoding LacZ gene and plasmid pRS22 encoding murine interleukin-12(IL-12)gene were used to bansfect cells in vitro or be rapidly injected into the vein of mice. Then LacZ expression was assayed in cultured cells and tissues by X-gal staining.The IL-12 level was tested in the supernatants of cultured cells and in the serum with ELISA. Results In the presence of RU486.30％ of the liver derived hepatic HepG2 cells were dyed blue while less than 1％of the HepG2 cells were blue colored in the absence of RU486. Less than 0.5％ of other non-hepatic cells were in blue with or without RU486. After transfection, the IL-12 level in the supernatants of HepG2 cells increased with increasing concentrations of RU486 treatment. After intravenous injection of plasmid pRS-LacZ,blue colored cells were observed only in liver tissue while induced by RU486. After intravenous injection of plasmid pRS22,the IL-12 expression level in serum was related with the dosage of RU486 or/and plasmid DNA. Conclusion Plasmid DNA containing RU486 regulatory system could open or close IL-12 gene expression by the addition or deletion of RU486. And the IL-12 expression level in serum could be regulated by altering the dose of plasmid DNA or/and RU486.