REPLICATION ORIGIN OF THE ESCHERICHIA-COLI K-12 CHROMOSOME - THE SIZE AND STRUCTURE OF THE MINIMUM DNA SEGMENT CARRYING THE INFORMATION FOR AUTONOMOUS REPLICATION
REPLICATION ORIGIN OF THE ESCHERICHIA-COLI K-12 CHROMOSOME - THE SIZE AND STRUCTURE OF THE MINIMUM DNA SEGMENT CARRYING THE INFORMATION FOR AUTONOMOUS REPLICATION
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DOI：
10.1007/bf00267207
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发表时间：
1980-01-01
期刊：
影响因子：
--
通讯作者：
HIROTA, Y
中科院分区：
文献类型：
--
作者：
OKA, A;SUGIMOTO, K;HIROTA, Y
A DNA fragment containing the replication origin of the E. coli K-12 chromosome was inserted in 2 orientations at either the BamHI or SalI site of pBR322 DNA. All the resulting hybrid plasmids replicated in both polA and polA+ cells, whereas pBR322 replicates only in polA+ cells. This characteristic provided a method for assaying the autonomously replicating ability (Ori function) of the E. coli origin. To define the minimum DNA region (Ori) that determines Ori function, deletions of various sizes were introduced from either side of the ori-containing segment in the hybrid plasmids by in vitro techniques, and the correlation between the Ori phenotype and nucleotide sequence of the deletion derivatives was analyzed. The left end of ori is between positions 23 and 35, and the right end is either position 266 or 267 in this nucleotide coordinate. Therefore, ori is present within a region of minimum 232 base pairs and maximum 245 base pairs in length. The Ori+ and Ori- phenotypes were clearly resolved at both sides of these boundaries by the above assay procedure. To obtain information about the effect of mutations in the internal region of the defined ori stretch, short sequences were inserted or deleted in vitro in the vicinity of several restriction sites within ori on the hybrid plasmids. Most of these plasmids carrying modified sequences showed Ori- phenotype, suggesting that most parts of the ori stretch play important roles in Ori function.
