人端粒酶RNA基因的克隆与鉴定

以人血基因组ＤＮＡ为模板,合成两段２０个寡聚核苷酸为引物,经过ＰＣＲ扩增,得到４８０ｂｐ的片段,克隆到ｐＭＤ１８－Ｔ载体中,经电泳、酶切、ＰＣＲ鉴定后测定序列。序列分析表明氙克隆的人端粒酶ＲＮＡ（ｈｕｍａｎ ｔｅｌｏｍｅａｓｅ ＲＮＡ,ｈＴＲ）基因含有４８０ｂｐ,包括约４５０ｂｐ的编码模板区主序列和约３０ｂｐ的上游调控区序列,其中模板区的１１个核苷酸（５’－ＣＵＡＡＣＣＣＵＡＡＣ－３’）合成端粒亚     

Organization of the human myoglobin gene.

Cross-hybridization of the grey seal myoglobin gene to human DNA detected a single human myoglobin gene plus an extensive family of sequences apparently related to the central exon of this gene. The functional human gene is 10.4 kb long and has a haemoglobin-like three exon/two intron structure with long non-coding regions similar to its seal homologue. At least 300 bp of 5'-flanking region are closely homologous between the two genes, with the exception of a divergent purine-rich region 68-114 bp upstream of the cap site. A diverged tandem repetitive sequence based on (GGAT)165 is located 1100-1750 bp upstream from the gene; internal homology units within this sequence suggest sequence homogenization by gene microconversions. A second 33-bp tandem repeat element in the first intron is flanked by a 9-bp direct repeat, shares homology with other tandem repetitive elements in the human genome and may represent a novel form of transposable element.     

Isolation and sequencing of mouse angiogenin DNA

The mouse genomic DNA for angiogenin, a potent blood vessel inducing protein, has been isolated from a bacteriophage library using the human angiogenin gene as a probe. The 1129 bp fragment contains 499 bp in the 5' flanking region, 192 bp in the 3' flanking region, and 438 bp coding for the mature protein (121 amino acids) and signal peptide (24 amino acids). Potential TATA box and AATAAA polyadenylation sequences are present, and a consensus sequence for an intron 3' boundary occurs 16 bp upstream of the Met-(24) codon, suggesting the presence of an intron in the 5' region. The protein sequence inferred from the DNA is 76% identical to that of human angiogenin, and matches the sequences obtained previously from tryptic peptides of a serum-derived mouse angiogenin. The critical catalytic residues of human angiogenin are conserved in the mouse protein, as are the six cysteines necessary for disulfide bond formation.     

人皮肤成纤维细胞中α1(Ⅰ)前胶原基因转录调控研究

为寻找纤维化形成中调控人Ⅰ型前胶原基因高水平转录的启动序列及其DNA结合蛋白 ,以人皮肤成纤维细胞α1(Ⅰ )前胶原基因转录起始点上游 - 2 5kb至 + 4 2bp的片段为靶序列 ,采用PCR、基因重组、报告基因测活、细胞基因转染技术比较不同长短启动子活性 .凝胶滞留实验 (EM SA)研究高启动活性片段相应的DNA结合蛋白 .基因转染高活性转录因子识别序列至靶细胞 ,探讨前胶原基因激活阻断的新手段 .结果表明 ,- 2 4 83～ + 4 2bp、 - 2 6 8～ + 4 2bp序列具有强启动调控活性 ,而 - 10 5～ + 4 2bp片段启动活性最低 .EMSA对高启动活性小片段DNA结合蛋白的分析提示 ,- 2 6 8～ + 4 2bp序列中存在转录因子Ap 1、Sp 1、NF 1的特异结合位点 .转染高活性转录因子识别序列Ap 1、Sp 1至靶细胞可竞争性阻断胶原基因启动转录激活 .研究提示 ,人α1(Ⅰ )前胶原基因 - 2 4 83～ + 4 2bp、 - 2 6 8～ + 4 2bp片段有高启动活性 .转录因子Ap 1、Sp 1、NF 1与 - 2 6 8～ + 4 2bp序列中相应识别序列的结合与其基础高转录活性有关 .转染高活性转录因子识别序列Ap 1、Sp 1可从转录水平阻断胶原基因的激活