Single-molecule observation of DNA replication repair pathways in E. coli

TL;DR

This study employs single-molecule microscopy to observe DNA replication repair pathways in E. coli, providing insights into bacterial responses to replication-blocking antibiotics.

Contribution

It introduces a novel single-molecule imaging platform to quantify replication stalling and repair processes in live bacteria.

Findings

Quantified the accumulation of repair proteins at replication blocks.

Demonstrated the use of fluorescently labeled DNA polymerase to monitor replication dynamics.

Established a quantitative method for studying bacterial DNA repair mechanisms.

Abstract

The method of action of many antibiotics is to interfere with DNA replication - quinolones trap DNA gyrase and topoisomerase proteins onto DNA while metronidazole causes single and double stranded breaks in DNA. To understand how bacteria respond to these drugs, it is important to understand the repair processes utilised when DNA replication is blocked. We have used tandem lac operators inserted into the chromosome bound by fluorescently labelled lac repressors as a model protein block to replication in E. coli. We have used dual-colour, alternating-laser, single-molecule narrowfield microscopy to quantify the amount of operator at the block and simultaneously image fluorescently labelled DNA polymerase. We anticipate use of this system as a quantitative platform to study replication stalling and repair proteins.