Inhibiting translation elongation can aid genome duplication in Escherichia coli

Kamila Katarzyna Myka, Michelle Hawkins, Aisha H Syeda, Milind K. Gupta, Caroline Meharg, Mark S. Dillingham, Nigel J. Savery, Robert G. Lloyd, Peter McGlynn

Research output: Contribution to journalArticlepeer-review


Conflicts between replication and transcription challenge chromosome duplication. Escherichia coli replisome movement along transcribed DNA is promoted by Rep and UvrD accessory helicases with Δrep ΔuvrD cells being inviable under rapid growth conditions. We have discovered that mutations in a tRNA gene, aspT, in an aminoacyl tRNA synthetase, AspRS, and in a translation factor needed for efficient proline-proline bond formation, EF-P, suppress Δrep ΔuvrD lethality. Thus replication-transcription conflicts can be alleviated by the partial sacrifice of a mechanism that reduces replicative barriers, namely translating ribosomes that reduce RNA polymerase backtracking. Suppression depends on RelA-directed synthesis of (p)ppGpp, a signalling molecule that reduces replication-transcription conflicts, with RelA activation requiring ribosomal pausing. Levels of (p)ppGpp in these suppressors also correlate inversely with the need for Rho activity, an RNA translocase that can bind to emerging transcripts and displace transcription complexes. These data illustrate the fine balance between different mechanisms in facilitating gene expression and genome duplication and demonstrate that accessory helicases are a major determinant of this balance. This balance is also critical for other aspects of bacterial survival: the mutations identified here increase persistence indicating that similar mutations could arise in naturally occurring bacterial populations facing antibiotic challenge.

Original languageEnglish
Pages (from-to)2571-2584
Number of pages14
JournalNucleic Acids Research
Issue number5
Early online date12 Dec 2016
Publication statusPublished - 17 Mar 2017

Bibliographical note

©The Author(s) 2016.


  • DNA Helicases
  • DNA Replication
  • Escherichia coli
  • Escherichia coli Proteins
  • Genome, Bacterial
  • Mutation
  • Peptide Chain Elongation, Translational
  • RNA, Transfer, Asp
  • Suppression, Genetic
  • Transfer RNA Aminoacylation
  • Journal Article

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