人Ⅰ型胶原基因第一内含子调节转录的研究

Study on the First Intron Regulating Transcription of Human α1(Ⅰ) Collagen Gene

人Ⅰ型胶原α１（Ⅰ）链（ＣＯＬⅠＡ１）基因内含子序列在不同细胞内有不同的转录调节活性．报道了含人ＣＯＬⅠＡ１基因内含子Ⅰ不同区段（＋５４４～＋８５５和＋８２０～＋１０９３）的重组质粒ｐＳＣＥＰＣＡＴ和ｐＳＣＩＰＣＡＴ的构建并转染人胚肌腱成纤维细胞和Ｔｃａ８１１３舌癌细胞．地高辛标记抗ＣＡＴＥＬＩＳＡ检测结果显示：ｐＳＣＥＰＣＡＴ在两种细胞均获表达；ｐＳＣＩＰＣＡＴ在人成纤维细胞未表达，但在舌癌细胞其表达量明显高于ｐＳＣＥＰＣＡＴ．这表明人ＣＯＬⅠＡ１基因内含子Ⅰ＋５４４～＋８５５区段增强氯霉素乙酰转移酶（ＣＡＴ）表达；＋８２０～＋１０９３区段则抑制人成纤维细胞但显著增强舌癌细胞的ＣＡＴ表达．

The first intron sequence of human α1(Ⅰ) collagen (COLⅠA1) gene has been shown to have differential activities of transcription regulation in a variety of tissue cells. To determine the activity of the first intron of COLⅠA1 gene and then utilize the regulatory elements to perform ectopic expression of foreign genes in human fibroblasts. Two novel recombinants pSCEPCAT and pSCIPCAT were constructed in which the intronic +544～+855 and +820～+1 093 segment of COLⅠA1 gene were cloned respectively in the upstream position of the promoter sequence of this gene followed by chloramphenical acetyltransferases (CAT) gene. Human fetal tendon fibroblasts and Tca 8113 tongue cancer cells in culture were transfected with the recombinants by using LipofectAMINETM, and then tested the expression level of CAT gene with DIGlabeled antiCAT ELISA. The results indicate that the first intronic +544～+855 segment of COLⅠA1 gene has an enhancing effect on the expression of CAT gene driven by the promoter in the tranfected human fetal tendon fibroblasts and Tca 8113 tongue cancer cells. Interestingly, the first intronic +820～+1 093 segment has strongly stimulating effect on the expression of the marker gene in the tongue cancer cells, but inhibitory effect in the fibroblasts.