TY - JOUR

T1 - Inhibition of Escherichia coli chromosome replication by rifampicin treatment or during the stringent response is overcome by de novo DnaA protein synthesis

AU - Riber, Leise

AU - Løbner-Olesen, Anders

N1 - This article is protected by copyright. All rights reserved.

PY - 2020

Y1 - 2020

N2 - Initiation of Escherichia coli chromosome replication is controlled by the DnaA initiator protein. Both rifampicin-mediated inhibition of transcription and ppGpp-induced changes in global transcription stops replication at the level of initiation. Here, we show that continued DnaA protein synthesis allows for replication initiation both during rifampicin treatment and during the stringent response when the ppGpp level is high. A reduction in or cessation of de novo DnaA synthesis therefore causes the initiation arrest in both cases. In accordance with this, inhibition of translation with chloramphenicol also stops initiations. The initiation arrest caused by rifampicin was faster than that caused by chloramphenicol, despite of the latter inhibiting DnaA accumulation immediately. During chloramphenicol treatment transcription is still ongoing and we suggest that transcriptional events in or near the origin, i.e. transcriptional activation, can allow for a few extra initiations when DnaA becomes limiting. We suggest, for both rifampicin treated cells and for cells accumulating ppGpp, that a turn-off of initiation from oriC requires a stop in de novo DnaA synthesis and that an additional lack of transcriptional activation enhances this process, i.e. leads to a faster initiation stop.

AB - Initiation of Escherichia coli chromosome replication is controlled by the DnaA initiator protein. Both rifampicin-mediated inhibition of transcription and ppGpp-induced changes in global transcription stops replication at the level of initiation. Here, we show that continued DnaA protein synthesis allows for replication initiation both during rifampicin treatment and during the stringent response when the ppGpp level is high. A reduction in or cessation of de novo DnaA synthesis therefore causes the initiation arrest in both cases. In accordance with this, inhibition of translation with chloramphenicol also stops initiations. The initiation arrest caused by rifampicin was faster than that caused by chloramphenicol, despite of the latter inhibiting DnaA accumulation immediately. During chloramphenicol treatment transcription is still ongoing and we suggest that transcriptional events in or near the origin, i.e. transcriptional activation, can allow for a few extra initiations when DnaA becomes limiting. We suggest, for both rifampicin treated cells and for cells accumulating ppGpp, that a turn-off of initiation from oriC requires a stop in de novo DnaA synthesis and that an additional lack of transcriptional activation enhances this process, i.e. leads to a faster initiation stop.

U2 - 10.1111/mmi.14531

DO - 10.1111/mmi.14531

M3 - Journal article

C2 - 32458540

VL - 114

SP - 906

EP - 919

JO - Molecular Microbiology

JF - Molecular Microbiology

SN - 0950-382X

IS - 6

ER -