Sleigh M J, Grigg G W
Biochem J. 1976 Apr 1;155(1):87-99. doi: 10.1042/bj1550087.
Stationary-phase Escherichia coli B cells transferred to new growth medium are initially resistant to net DNA breakage by low concentrations of phleomycin, and become sensitive as DNA replication commences. From studies with inhibitors of various stages of the DNA replication cycle it is evident that it is not DNA synthesis itself that is required for induction of DNA breakage by phleomycin, but events associated with the initiation of DNA replication. Termination of replication in the absence of further initiaiton results in resistance to phleomycin. The cellular change responsible for changes in sensitivity to phleomycin could be the attachment of the bacterial chromosome to the cell membrane at initiation and detachment on termination of replication, suggesting an alteration in the balance between cellular DNA breakage and repair processes for membrane-associated compared with non-membrane-associated DNA.
转移至新生长培养基中的稳定期大肠杆菌B细胞最初对低浓度的博来霉素导致的净DNA断裂具有抗性,而随着DNA复制开始则变得敏感。通过对DNA复制周期各个阶段抑制剂的研究表明,博来霉素诱导DNA断裂并非需要DNA合成本身,而是与DNA复制起始相关的事件。在没有进一步起始的情况下复制终止会导致对博来霉素产生抗性。导致对博来霉素敏感性变化的细胞改变可能是细菌染色体在复制起始时附着于细胞膜而在复制终止时脱离,这表明与非膜相关DNA相比,膜相关DNA的细胞DNA断裂和修复过程之间的平衡发生了改变。