Hidaka M, Akiyama M, Horiuchi T
Department of Molecular Biology, Graduate School of Medical Science, Kyushu University, Fukuoka, Japan.
Cell. 1988 Nov 4;55(3):467-75. doi: 10.1016/0092-8674(88)90033-5.
Using the "Ter assay" we developed, three separate replication terminus (terC1, terC2, and terC3) sites on the E. coli chromosome were identified. The locations are at 28.3, 35.6, and 33.9 min on the linkage map, respectively. The terC1 site can block the counter-clockwise replication fork only, while the terC2 and terC3 sites inhibit the clockwise fork traveling on the chromosome. DNA sequences of the terC sites required for termination of DNA replication are highly homologous to those of terminus (terR) sites of the R6K plasmid, and the 21 bp consensus DNA sequence of terC is 5'-(A or T) TTAGTTACAACAT (A or C) CT (A or T) (A or T) (A or T) T-3'. In addition, all Ter active pUC-terC plasmids had a low copy number and were unstable in the host cells.
使用我们开发的“Ter 分析”，在大肠杆菌染色体上鉴定出了三个独立的复制终止位点（terC1、terC2 和 terC3）。这些位点在连锁图上的位置分别为 28.3、35.6 和 33.9 分钟处。terC1 位点仅能阻止逆时针方向的复制叉，而 terC2 和 terC3 位点则抑制顺时针方向的复制叉在染色体上移动。DNA 复制终止所需的 terC 位点的 DNA 序列与 R6K 质粒的终止（terR）位点的序列高度同源，terC 的 21bp 共有 DNA 序列为 5'-(A 或 T)TTAGTTACAACAT(A 或 C)CT(A 或 T)(A 或 T)(A 或 T)T-3'。此外，所有具有 Ter 活性的 pUC-terC 质粒拷贝数低，且在宿主细胞中不稳定。
