应用抑制性消减杂交技术筛选转化生长因子β1刺激LX02细胞的反式调节基因

目的 构建转化生长因子(TGF)β1刺激大鼠肝星状细胞(LX02)反式调节基因的cDNA消减文库,筛选并克隆TGF β1反式调节相关基因,以阐明TGF β1介导肝纤维化的分子生物学机制.方法 以TGF β1刺激LX02细胞,同时以磷酸盐缓冲液刺激的LX02细胞作为对照.提取mRNA并逆转录为cDNA,经Rsa Ⅰ酶切后,将实验组cDNA分成两组,分别与两种不同的接头衔接,再与对照组cDNA进行两次消减杂交及两次抑制性多聚酶链反应.将产物与pGEM-Teasy载体连接,构建cDNA消减文库,并转染大肠杆菌进行文库扩增;随机挑选克隆经PCR扩增后进行测序及同源性分析. 结果成功构建了TGF β1刺激LX02细胞反式调节基因的cDNA消减文库.文库扩增后得到146个200～1000bp插入片段的阳性克隆;随机挑取其中35个克隆进行测序,30个列序成功,并通过生物信息学分析发现有28个与已知基因序列和2个与未知功能基因序列高度同源.结论 应用抑制性消减杂交技术成功构建了TGF β1刺激LX02细胞反式调节基因的cDNA消减文库,筛选到一些与细胞生长调节、蛋白质合成,信号传导、细胞外基质代谢、扰脂质过氧化等密切相关的蛋白质编码基因,为进一步阐明TGF β1介导肝纤维化的分子生物学机制提供了线索.

Screening and cloning genes transactivated by TGF beta 1 in hepatic stellate cells using suppression subtractive hybridization technique

Objectives To construct a eDNA subtractive library of genes transactivated by TGF beta 1 in LX02 hepatic stellate cells (HSC); to screen and to clone the regulated genes transactivated by TGF beta 1; and to elucidate the molecular biological mechanism of hepatic fibrosis mediated by TGF beta 1. Methods mRNA was isolated from HSC treated with TGF beta 1 or with PBS (as controls). Suppression subtractive hybridization (SSH) technique was employed to analyze the differentially expressed DNA sequence between the two groups. After restriction enzyme Rsa I digestion, small size cDNAs were obtained. Then tester cDNA was divided into two groups and ligated to specific adaptor 1 and adaptor 2, respectively. After tester cDNA was hybridized with driver cDNA twice and underwent polymerase chain reaction twice it then was subcloned into pGEM-Teasy plasmid vectors to set up the subtractive library. Amplification of the library was carded out with E. coli strain DH5 α. The cDNA was sequenced and analyzed in GenBank with Blast search. Results The subtractive cDNA library of genes transactivated by TGF beta 1 in HSC was constructed successfully. The amplified library contained 146 positive clones, which contained 200-1000 bp of inserts. Randomly, thirty clones were analyzed by sequencing and bioinformatics, consisting of 28 known genes and 2 unknown genes. Conclusions The subtractive cDNA library of genes transactivated by TGF beta 1 in HSC using SSH technique was constructed successfully. Some gene coding proteins are those involved in cell growth regulation, protein synthesis, signal transduction, extraeellular matrix metabolism, and anti-lipid peroxidative, which gives us some new clues for the study of the mechanism of liver fibrosis.