Hansen E B, Yarmolinsky M B
Proc Natl Acad Sci U S A. 1986 Jun;83(12):4423-7. doi: 10.1073/pnas.83.12.4423.
Nonparticipation of the bacterial dnaA gene in plasmid replication has been assumed to be the general rule. In conditional dnaA mutants of Escherichia coli, only plasmid pSC101 has been shown to have a dnaA requirement. Experiments with dnaA null mutants of E. coli, presented here, show that dnaA plays a critical and direct role in the replication of miniplasmids derived from P1 and F as it does in the initiation of bacterial replication. Evidence is also presented for the existence of a dnaA-independent secondary replicon of P1 that is able to drive bacterial chromosome replication but is inadequate to support the maintenance of P1 as a plasmid in E. coli.
细菌的dnaA基因不参与质粒复制被认为是普遍规律。在大肠杆菌的条件性dnaA突变体中，只有质粒pSC101被证明有dnaA需求。本文展示的对大肠杆菌dnaA缺失突变体的实验表明，dnaA在源自P1和F的微型质粒复制中起着关键且直接的作用，就如同它在细菌复制起始过程中所起的作用一样。还提供了证据表明存在一个不依赖dnaA的P1二级复制子，它能够驱动细菌染色体复制，但不足以支持P1作为大肠杆菌中的质粒得以维持。
