TEMPERATURE-SENSITIVE MUTANTS FOR REPLICATION OF PLASMIDS IN ESCHERICHIA-COLI - REQUIREMENT FOR DEOXYRIBONUCLEIC ACID POLYMERASE I IN REPLICATION OF PLASMID COLE
TEMPERATURE-SENSITIVE MUTANTS FOR REPLICATION OF PLASMIDS IN ESCHERICHIA-COLI - REQUIREMENT FOR DEOXYRIBONUCLEIC ACID POLYMERASE I IN REPLICATION OF PLASMID COLE
复制标题
DOI：
10.1128/jb.114.3.1116-1124.1973
复制
发表时间：
1973-01-01
影响因子：
3.2
通讯作者：
HELINSKI, DR
中科院分区：
文献类型：
--
作者：
KINGSBURY, DT;HELINSKI, DR
大肠杆菌共变菌（polA1）在脱氧核糖核酸（DNA）聚合酶I （EC 2.7.7.7）中存在缺陷，不能维持ColE1 (ColE1)，而在该菌株中，一些性因子质粒正常维持。含有这些性因子质粒的pola1突变株不表现出易于检测的质粒诱导聚合酶活性。A series of一系列；对ColE1维持温度敏感，但能够维持其他质粒的共变子被分离出来，并被证明可分为两个表型组。一组突变体在43℃时ColE1的维持有缺陷，但表现出正常的DNA聚合酶I活性。第二组的突变图位于e基因的极点。携带这些突变的细菌对甲基甲磺酸盐（MMS）敏感。选择抗MMS或维持ColE1能力的回调剂对这两种性质都是正常的。与野生型酶相比，其中两个突变体的DNA聚合酶I表现出明显的温度敏感性。对DNA聚合酶I在ColE1维持中的作用的研究表明，它对质粒的正常复制至关重要。此外，colv促进ColE1的偶联转移和质粒在受体细胞中的建立需要在供体细胞和受体细胞中都存在功能性DNA聚合酶I。
AnEscherichia colimutant (polA1), defective in deoxyribonucleic acid (DNA) polymerase I, (EC 2.7.7.7) is unable to maintain colicinogenic factor E1 (ColE1), whereas several sex factor plasmids are maintained normally in this strain.polA1mutant strains containing these sex factor plasmids do not exhibit a readily detectable plasmid-induced polymerase activity. A series ofE. colimutants that are temperature sensitive for ColE1 maintenance, but able to maintain other plasmids, were isolated and shown to fall into two phenotypic groups. Mutants in one group are defective specifically in ColE1 maintenance at 43 C, but exhibit normal DNA polymerase I activity. Mutations in the second group map in thepolAgene ofE. coli, and bacteria carrying these mutations are sensitive to methylmethanesulfonate (MMS). Revertants that were selected either for MMS resistance or the ability to maintain ColE1 were normal for both properties. The DNA polymerase I enzyme of two of these mutants shows a pronounced temperature sensitivity when compared to the wild-type enzyme. An examination of the role of DNA polymerase I in ColE1 maintenance indicates that it is essential for normal replication of the plasmid. In addition, the presence of a functional DNA polymerase I in both the donor and recipient cell is required for the ColV-promoted conjugal transfer of ColE1 and establishment of the plasmid in the recipient cell.