title: [The effects of TorR protein on initiation of DNA replication in Escherichia coli].
abstract: The two-component systems, which could sense and respond to environmental changes, widely exist in bacteria as a signal transduction pathway. The bacterial CckA/CtrA, ArcA/ArcB and PhoP/PhoQ two-component systems are associated with initiation of DNA replication and cell division, however, the effects of the TorS/TorR system on cell cycle and DNA replication remains unknown. The TorS/TorR system in Escherichia coli can sense changes in trimethylamine oxide (TMAO) concentration around the cells. However, it is unknown if it also affects initiation of DNA replication. We detected DNA replication patterns in ΔtorS and ΔtorR mutant strains by flow cytometry. We found that the average number of replication origins (oriCs) per cell and doubling time in ΔtorS mutants were the same while the average number of oriCs in ΔtorR mutants was increased compared with that in wild-type cells. These results indicated that absence of TorR led to an earlier initiation of DNA replication than that in wild-type cells. Strangely, neither overexpression of TorR nor co-expression of TorR and TorS could restore ΔtorR mutant phenotype to the wild type. However, overexpression of SufD in both wild type and ΔtorR mutants promoted initiation of DNA replication, while mutation of SufD delayed it in ΔtorR mutants. Thus, TorR may affect initiation of DNA replication indirectly through regulating gene expression of sufD.
authors: School of Life Sciences, Inner Mongolia University, Hohhot 010021, China.
authors: Yuan
authors: Y
authors: Yao
authors: School of Life Sciences, Inner Mongolia University, Hohhot 010021, China.
authors: Jia-Xin
authors: JX
authors: Qiao
authors: School of Life Sciences, Inner Mongolia University, Hohhot 010021, China.
authors: Jing
authors: J
authors: Li
authors: School of Life Sciences, Inner Mongolia University, Hohhot 010021, China.
authors: Hui
authors: H
authors: Li
authors: School of Life Sciences, Inner Mongolia University, Hohhot 010021, China.
authors: Morigen
mesh_terms: D002455:Cell Division; D004261:DNA Replication; D004926:Escherichia coli / Q000166:cytology / Q000235:genetics* / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D010770:Phosphotransferases / Q000235:genetics / Q000378:metabolism*; D018741:Replication Origin; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D029968:Escherichia coli Proteins; C089364:TorR protein, E coli; D014157:Transcription Factors; D010770:Phosphotransferases; C103806:TorS protein, E coli