The world's first wiki where authorship really matters (Nature Genetics, 2008). Due credit and reputation for authors. Imagine a global collaborative knowledge base for original thoughts. Search thousands of articles and collaborate with scientists around the globe.

wikigene or wiki gene protein drug chemical gene disease author authorship tracking collaborative publishing evolutionary knowledge reputation system wiki2.0 global collaboration genes proteins drugs chemicals diseases compound
Hoffmann, R. A wiki for the life sciences where authorship matters. Nature Genetics (2008)
Gene Review

dnaQ  -  DNA polymerase III subunit epsilon

Escherichia coli O157:H7 str. EDL933

Welcome! If you are familiar with the subject of this article, you can contribute to this open access knowledge base by deleting incorrect information, restructuring or completely rewriting any text. Read more.

Disease relevance of dnaQ


High impact information on dnaQ

  • We have constructed plasmid pIP11, in which the dnaQ gene is fused to the strong tac (trp-lac) promoter [3].
  • Mutations in the dnaQ gene, which encodes the proofreading epsilon-subunit of the DNA polymerase III holoenzyme, lead to a mutator phenotype caused by enhanced error rates during DNA replication [4].
  • When transfections were carried out in dnaQ strains that are impaired in 3'-->5'exonuclease activity of DNA polymerase III, frame-shift mutagenesis increased 5-7-fold. dGAP-induced frame-shifts in the (CG)3 sequence, therefore, varied from 2% to 17% depending on the state of repair of the host cells [5].
  • This region contains the dnaE and dnaQ genes, which encode, respectively, the DNA polymerase (alpha subunit) and 3' exonucleolytic proofreading activity (epsilon subunit) of DNA polymerase III holoenzyme, the enzyme primarily responsible for replicating the bacterial chromosome [6].
  • Chromosome replication in Escherichia coli is accomplished by the multimeric enzyme DNA polymerase III; the relevance, in vivo, of the epsilon subunit (encoded by dnaQ) for processivity and fidelity of DNA polymerase III has been evaluated [7].

Biological context of dnaQ

  • The C-terminal domain of dnaQ contains the polymerase binding site [8].
  • The dnaQ (mutD) gene product which encodes the epsilon-subunit of the DNA polymerase III holoenzyme has a central role in controlling the fidelity of DNA replication because both mutD5 and dnaQ49 mutations severely decrease the 3'-5' exonucleolytic editing capacity [9].
  • In contrast, a dnaQ null mutant exhibited poor growth, chronic SOS induction, and an elevated spontaneous mutation rate, like dnaQ null mutants of S. typhimurium described previously [10].
  • This is the first evidence for the inducibility of dnaQ gene expression (and possibly of other genes of the DNA polymerase II holoenzyme) and is discussed in relation to DNA repair mechanisms [11].


  1. Mutator and antimutator effects of the bacteriophage P1 hot gene product. Chikova, A.K., Schaaper, R.M. J. Bacteriol. (2006) [Pubmed]
  2. Mutator strains of Escherichia coli, mutD and dnaQ, with defective exonucleolytic editing by DNA polymerase III holoenzyme. Echols, H., Lu, C., Burgers, P.M. Proc. Natl. Acad. Sci. U.S.A. (1983) [Pubmed]
  3. Overproduction of the epsilon subunit of DNA polymerase III counteracts the SOS mutagenic response of Escherichia coli. Jonczyk, P., Fijalkowska, I., Ciesla, Z. Proc. Natl. Acad. Sci. U.S.A. (1988) [Pubmed]
  4. The ssb-113 allele suppresses the dnaQ49 mutator and alters DNA supercoiling in Escherichia coli. Quiñones, A., Neumann, S. Mol. Microbiol. (1997) [Pubmed]
  5. Site-specific frame-shift mutagenesis by the 1-nitropyrene-DNA adduct N-(deoxyguanosin-8-y1)-1-aminopyrene located in the (CG)3 sequence: effects of SOS, proofreading, and mismatch repair. Malia, S.A., Vyas, R.R., Basu, A.K. Biochemistry (1996) [Pubmed]
  6. Mutants of Escherichia coli with increased fidelity of DNA replication. Fijalkowska, I.J., Dunn, R.L., Schaaper, R.M. Genetics (1993) [Pubmed]
  7. Silencing of the gene coding for the epsilon subunit of DNA polymerase III slows down the growth rate of Escherichia coli populations. Stefan, A., Reggiani, L., Cianchetta, S., Radeghieri, A., Gonzalez Vara y Rodriguez, A., Hochkoeppler, A. FEBS Lett. (2003) [Pubmed]
  8. The C-terminal domain of dnaQ contains the polymerase binding site. Taft-Benz, S.A., Schaaper, R.M. J. Bacteriol. (1999) [Pubmed]
  9. Mutational specificity of a proof-reading defective Escherichia coli dnaQ49 mutator. Piechocki, R., Kupper, D., Quiñones, A., Langhammer, R. Mol. Gen. Genet. (1986) [Pubmed]
  10. holE, the gene coding for the theta subunit of DNA polymerase III of Escherichia coli: characterization of a holE mutant and comparison with a dnaQ (epsilon-subunit) mutant. Slater, S.C., Lifsics, M.R., O'Donnell, M., Maurer, R. J. Bacteriol. (1994) [Pubmed]
  11. Expression of the Escherichia coli dnaQ (mutD) gene is inducible. Quiñones, A., Piechocki, R., Messer, W. Mol. Gen. Genet. (1988) [Pubmed]
WikiGenes - Universities