人结核杆菌热休克蛋白70和卡介苗α抗原基因启动子序列测定  

Sequencing of the Promoters of Mycobacterium Tuberculosis Heat Shock Protein 70 and BCG α Antigen Gene

作　　者：程继忠[1] 梁驹卿[1] 肖红[1] 海涛[2] 皇甫永穆 

机构地区：[1]同济医科大学实验医学研究中心医学分子生物学研究室,武汉430030 [2]同济医科大学职业医学研究所,武汉430030

出　　处：《同济医科大学学报》1997年第5期331-335,共5页Acta Universitatis Medicinae Tongji

基　　金：总理基金!No.94-Y-19;国家自然科学基金!No.39480022;卫生部基金!No.94-1-144资助

摘　　要：用T7DNA聚合酶测序系统测定了人结核杆菌热休克蛋白70（hsp70）基因的启动子序列和卡介苗（BCG）α基因的启动子和信号肽序列，并比较了它们与大肠杆菌（E.coli）和其它分枝杆菌启动子之间的异同。结果所测的hsp70启动子序列为人结核杆菌hsp70编码基因起始密码（ATG）上游150个脱氧核苷酸，其中在ATG上游—12～—8核苷酸处有核糖体结合位点（SD序列）GGAGG，在RNA聚合酶的结合位点（RNApolymerase－bindingsite，RBS）区含有与E．coli相同的三核苷酸高度保守序列TTG。这些序列与E．coli5＇端调控区同源。在hsp70基因调控序列-10区两侧有反向重复序列TGCAGT，构成5＇端的茎环结构。其它分枝杆菌hsp基因启动子调控区均有类似的结构。对BCGα基因启动子和信号肽序列的测定，发现其启动子序列与hsp基因的SD、-10和-35序列有一定的区别，其序列分别为AAAGG、TATGTT、TCGACA。在ATG后的120个核苷酸序列所编码肽链具有信号肽的特征，在碱性氨基酸后紧跟一段疏水区，含有能被信号肽酶识别的Ala－X－Ala结构。The promoter of Mycobacterium tuberculosis heat shock protein 70(hsp 70) and the promoter and signal pepitide of BCG α antigen gene were sequenced by the Sanger's chain-termination method,using T7 DNA polymerase sequencing system,and were compared with promoters of E. coli and other Mycobacterial genes. Hsp70 promoter sequences 150 nucleotide upstream of the proposed initiation codon ATG were determined.At position-12～-8, there was sequence GGAGG which was a perfect match with the E. coli ribosome-binding site (SD sequence). The RNA polymerase-binding site (RBS), which was composed of-35 and-10 regions of Mycobacterium hsp70 gene promoter, contains the highly conserved 3 nucleotide TTG that was the same as E.coli consensus sequences. These sequences were homologous t0 5' regulatory sequences of E. coli's. An dyad symmetry sequence TGCAGT which occurred in-10 flanking region of the hsp70 promoter, formed a hairpin loop structures. Other Mycobacterial upstream regulatory sequences had the similar elements. The regulatory region of BCG α antigen gene was different in some extent from those of E. coli and Mycobacterial hsp gene in SD, - 10 and - 35 sequences, which were AAAGG, TATGTT and TCGACA respectively. The peptide chain encoded by the 120bp downstream of the initiation codon ATG had signal peptide characteristics: basic amino acid, followed by hydrophobic dormains, and a signal peptidase recognition sequence Ala-X-Ala.

关 键 词：结核杆菌 卡介苗 启动子 热休克蛋白 

分 类 号：R378.911[医药卫生—病原生物学] R186.2[医药卫生—基础医学]