title: DNA replication fidelity in Mycobacterium tuberculosis is mediated by an ancestral prokaryotic proofreader.
abstract: The DNA replication machinery is an important target for antibiotic development in increasingly drug-resistant bacteria, including Mycobacterium tuberculosis. Although blocking DNA replication leads to cell death, disrupting the processes used to ensure replication fidelity can accelerate mutation and the evolution of drug resistance. In Escherichia coli, the proofreading subunit of the replisome, the ɛ exonuclease, is essential for high-fidelity DNA replication; however, we find that the corresponding subunit is completely dispensable in M. tuberculosis. Rather, the mycobacterial replicative polymerase DnaE1 itself encodes an editing function that proofreads DNA replication, mediated by an intrinsic 3'-5' exonuclease activity within its PHP domain. Inactivation of the DnaE1 PHP domain increases the mutation rate by more than 3,000-fold. Moreover, phylogenetic analysis of DNA replication proofreading in the bacterial kingdom suggests that E. coli is a phylogenetic outlier and that PHP domain-mediated proofreading is widely conserved and indeed may be the ancestral prokaryotic proofreader.
authors.affiliation: Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, Massachusetts, USA.
authors.forename: Jeremy M
authors.initials: JM
authors.lastname: Rock
authors.affiliation: Medical Research Council (MRC) Laboratory of Molecular Biology, Cambridge, UK.
authors.forename: Ulla F
authors.initials: UF
authors.lastname: Lang
authors.affiliation: Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, Massachusetts, USA.
authors.forename: Michael R
authors.initials: MR
authors.lastname: Chase
authors.affiliation: 1] Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, Massachusetts, USA. [2] Broad Institute of MIT and Harvard, Cambridge, Massachusetts, USA.
authors.forename: Christopher B
authors.initials: CB
authors.lastname: Ford
authors.affiliation: Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, Massachusetts, USA.
authors.forename: Elias R
authors.initials: ER
authors.lastname: Gerrick
authors.affiliation: Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, Massachusetts, USA.
authors.forename: Richa
authors.initials: R
authors.lastname: Gawande
authors.affiliation: 1] Swiss Tropical and Public Health Institute, Basel, Switzerland. [2] University of Basel, Basel, Switzerland.
authors.forename: Mireia
authors.initials: M
authors.lastname: Coscolla
authors.affiliation: 1] Swiss Tropical and Public Health Institute, Basel, Switzerland. [2] University of Basel, Basel, Switzerland.
authors.forename: Sebastien
authors.initials: S
authors.lastname: Gagneux
authors.affiliation: 1] Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, Massachusetts, USA. [2] Broad Institute of MIT and Harvard, Cambridge, Massachusetts, USA. [3] Ragon Institute of Massachusetts General Hospital, Harvard and Massachusetts Institute of Technology, Cambridge, Massachusetts, USA.
authors.forename: Sarah M
authors.initials: SM
authors.lastname: Fortune
authors.affiliation: Medical Research Council (MRC) Laboratory of Molecular Biology, Cambridge, UK.
authors.forename: Meindert H
authors.initials: MH
authors.lastname: Lamers
mesh_terms: D000595:Amino Acid Sequence; D000995:Antitubercular Agents / Q000494:pharmacology; D001426:Bacterial Proteins / Q000235:genetics*; D004258:DNA Polymerase III / Q000235:genetics*; D004261:DNA Replication; D004269:DNA, Bacterial / Q000235:genetics; D024881:Drug Resistance, Bacterial; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D009169:Mycobacterium tuberculosis / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics; D010641:Phenotype; D010802:Phylogeny; D020641:Polymorphism, Single Nucleotide
chemical_list: D000995:Antitubercular Agents; D001426:Bacterial Proteins; D004269:DNA, Bacterial; C074904:DNA polymerase III, alpha subunit; D004258:DNA Polymerase III