Sarafanov A G, Timofeeva M Ia, Bannikov V M, Zakhar'ev V M, Mamaeva O K, Tikhomirova T I, Baev A A
Mol Biol (Mosk). 1995 Mar-Apr;29(2):287-93.
Primary structure was determined for the recently cloned f1/BglII-fragment [19] containing 2102 b.p. of the human tissue plasminogen activator (tPA) gene 3' end and adjacent DNA region. Computer analysis has revealed an Alu-repeat 820 b.p. downstream the tPA gene; the sequence proved to have a considerable homology (86-88%) with the Alus from the 3'-untranslated regions (3'UTRs) of cytochrome P-450, lysozyme and p53 protein human mRNAs. The same homology was estimated for this Alu in reversed orientation and Alus from the 3'UTRs of some other human mRNAs. In contrast, the homology between this 3' end tPA gene flanking Alu-repeat and other Alus dispersed throughout the gene introns either direct or reversed, was less than 70%. The polyadenylation signal AATAAA downstream the Alu and two nearby signals CACAG and GTGTT resembling consensus sequences CACAG and YGTGTTYY, respectively, were also detected. The two latter motifs located close to the 3' ends in most mammalian genes are likely to regulate mature mRNA formation. The comparison of the sequenced spaser flank adjacent to the tPA gene with short homologous sequence from the same genomic region primary structure reported previously has revealed discrepancies (substitutions, deletions or insertions) in 21 nucleotide positions. The nucleotide sequence of E. coli uvrB gene fragment (980 b.p.) is also reported. This E. coli gene fragment was cloned accidentally within the f1/BglII-fragment being an artifact of the host-vector system used.
已确定最近克隆的包含2102个碱基对的人组织纤溶酶原激活剂(tPA)基因3'端及相邻DNA区域的f1/BglII片段的一级结构。计算机分析显示,在tPA基因下游820个碱基对处有一个Alu重复序列;该序列与细胞色素P - 450、溶菌酶和p53蛋白人mRNA的3'非翻译区(3'UTR)中的Alu具有相当高的同源性(86 - 88%)。对于该反向的Alu与其他一些人mRNA的3'UTR中的Alu,也估计有相同的同源性。相比之下,该tPA基因3'端侧翼的Alu重复序列与分散在基因内含子中的其他Alu(正向或反向)之间的同源性小于70%。还检测到Alu下游的多聚腺苷酸化信号AATAAA以及另外两个附近的信号CACAG和GTGTT,它们分别类似于共有序列CACAG和YGTGTTYY。在大多数哺乳动物基因中,靠近3'端的后两个基序可能调节成熟mRNA的形成。将tPA基因相邻的已测序间隔区与先前报道的同一基因组区域一级结构中的短同源序列进行比较,发现在21个核苷酸位置存在差异(替换、缺失或插入)。还报道了大肠杆菌uvrB基因片段(980个碱基对)的核苷酸序列。该大肠杆菌基因片段是在f1/BglII片段内意外克隆的,是所用宿主 - 载体系统的一个假象。