Horiuchi T, Hidaka M
Graduate School of Medical Science, Department of Molecular Biology, Kyushu University, Fukuoka, Japan.
Cell. 1988 Aug 12;54(4):515-23. doi: 10.1016/0092-8674(88)90073-6.
The DNA replication terminus (terR) of the R6K plasmid located on a 216 bp Alul fragment (Alu216) can block progress of the DNA replication fork. We previously developed an electrophoresis assay that allows detection of terminus activity on any DNA fragment cloned in the pUC vector. For precise identification of terR, we tested Alu216, its subfragments, and synthetic oligonucleotides by this assay. We found terR to be composed of a pair of separable sites, terR1 and terR2, each of which can block the DNA replication fork traveling in a specific but not the opposite direction. Both terR sites were composed of 22 nucleotides containing the repeated 20 bp sequence 5'-TAGTTACAACAC(A or T) CAA(G or T) AGA-3', located 73 bp apart in the inverted position of Alu216. A DNA homology search suggested that the R6K plasmid and the E. coli chromosome share a common termination system.
位于216 bp AluI片段（Alu216）上的R6K质粒的DNA复制终止子（terR）可阻断DNA复制叉的前进。我们之前开发了一种电泳检测方法，可检测克隆于pUC载体中的任何DNA片段上的终止子活性。为了精确鉴定terR，我们用该检测方法对Alu216、其亚片段和合成寡核苷酸进行了测试。我们发现terR由一对可分离的位点terR1和terR2组成，每个位点都能阻断沿特定方向而非相反方向移动的DNA复制叉。两个terR位点均由22个核苷酸组成，包含重复的20 bp序列5'-TAGTTACAACAC(A或T)CAA(G或T)AGA-3'，在Alu216的反向位置上相隔73 bp。DNA同源性搜索表明，R6K质粒和大肠杆菌染色体共有一个共同的终止系统。
