scholarly journals Examination of the Role of DNA Polymerase Proofreading in the Mutator Effect of Miscoding tRNAs

1998 ◽  
Vol 180 (21) ◽  
pp. 5712-5717 ◽  
Author(s):  
Malgorzata M. Slupska ◽  
Angela G. King ◽  
Louise I. Lu ◽  
Rose H. Lin ◽  
Emily F. Mao ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Aspartic Acid ◽  
Dna Polymerase ◽  
Mutation Rate ◽  
Mutator Phenotype ◽  
Polymerase Iii ◽  
In Series ◽  
Mutator Effect

ABSTRACT We previously described Escherichia coli mutator tRNAs that insert glycine in place of aspartic acid and postulated that the elevated mutation rate results from generating a mutator polymerase. We suggested that the proofreading subunit of polymerase III, ɛ, is a likely target for the aspartic acid-to-glycine change that leads to a lowered fidelity of replication, since the altered ɛ subunits resulting from this substitution (approximately 1% of the time) are sufficient to create a mutator effect, based on several observations of mutDalleles. In the present work, we extended the study of specificmutD alleles and constructed 16 altered mutDgenes by replacing each aspartic acid codon, in series, with a glycine codon in the dnaQ gene that encodes ɛ. We show that three of these genes confer a strong mutator effect. We have also looked for new mutator tRNAs and have found one: a glycine tRNA that inserts glycine at histidine codons. We then replaced each of the seven histidine codons in the mutD gene with glycine codons and found that in two cases, a strong mutator phenotype results. These findings are consistent with the ɛ subunit playing a major role in the mutator effect of misreading tRNAs.

scholarly journals Mutator Phenotype Resulting from DNA Polymerase IV Overproduction in Escherichia coli: Preferential Mutagenesis on the Lagging Strand

2005 ◽  
Vol 187 (19) ◽  
pp. 6862-6866 ◽  
Author(s):  
Wojciech Kuban ◽  
Magdalena Banach-Orlowska ◽  
Malgorzata Bialoskorska ◽  
Aleksandra Lipowska ◽  
Roel M. Schaaper ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Dna Polymerase ◽  
Mutator Phenotype ◽  
Polymerase Iii ◽  
Mutator Activity ◽  
Mutator Effect ◽  
Dna Polymerase Iv ◽  
Lagging Strand

ABSTRACT We investigated the mutator effect resulting from overproduction of Escherichia coli DNA polymerase IV. Using lac mutational targets in the two possible orientations on the chromosome, we observed preferential mutagenesis during lagging strand synthesis. The mutator activity likely results from extension of mismatches produced by polymerase III holoenzyme.

scholarly journals Role of DNA Polymerase IV in Escherichia coli SOS Mutator Activity

2006 ◽  
Vol 188 (22) ◽  
pp. 7977-7980 ◽  
Author(s):  
Wojciech Kuban ◽  
Magdalena Banach-Orlowska ◽  
Roel M. Schaaper ◽  
Piotr Jonczyk ◽  
Iwona J. Fijalkowska
Keyword(s):  
Escherichia Coli ◽  
Gene Product ◽  
Dna Polymerase ◽  
Constitutive Expression ◽  
Significant Fraction ◽  
Mutator Phenotype ◽  
Mutator Activity ◽  
Dna Polymerase V ◽  
Dna Polymerase Iv

ABSTRACT Constitutive expression of the SOS regulon in Escherichia coli recA730 strains leads to a mutator phenotype (SOS mutator) that is dependent on DNA polymerase V (umuDC gene product). Here we show that a significant fraction of this effect also requires DNA polymerase IV (dinB gene product).

scholarly journals The interaction of DNA polymerase III and the product of the Escherichia coli mutator gene, mutD.

1984 ◽  
Vol 259 (9) ◽  
pp. 5567-5573
Author(s):  
R DiFrancesco ◽  
S K Bhatnagar ◽  
A Brown ◽  
M J Bessman
Keyword(s):  
Escherichia Coli ◽  
Dna Polymerase ◽  
Dna Polymerase Iii ◽  
Mutator Gene ◽  
Polymerase Iii

scholarly journals Antimutator mutations in the alpha subunit of Escherichia coli DNA polymerase III: identification of the responsible mutations and alignment with other DNA polymerases.

Genetics ◽  
1993 ◽  
Vol 134 (4) ◽  
pp. 1039-1044 ◽  
Author(s):  
I J Fijalkowska ◽  
R M Schaaper
Keyword(s):  
Escherichia Coli ◽  
Amino Acid ◽  
Dna Polymerase ◽  
Dna Polymerases ◽  
Alpha Subunit ◽  
Sequence Motifs ◽  
Dna Polymerase Iii ◽  
Conserved Sequence ◽  
Polymerase Iii ◽  
Dna Replication Errors

Abstract The dnaE gene of Escherichia coli encodes the DNA polymerase (alpha subunit) of the main replicative enzyme, DNA polymerase III holoenzyme. We have previously identified this gene as the site of a series of seven antimutator mutations that specifically decrease the level of DNA replication errors. Here we report the nucleotide sequence changes in each of the different antimutator dnaE alleles. For each a single, but different, amino acid substitution was found among the 1,160 amino acids of the protein. The observed substitutions are generally nonconservative. All affected residues are located in the central one-third of the protein. Some insight into the function of the regions of polymerase III containing the affected residues was obtained by amino acid alignment with other DNA polymerases. We followed the principles developed in 1990 by M. Delarue et al. who have identified in DNA polymerases from a large number of prokaryotic and eukaryotic sources three highly conserved sequence motifs, which are suggested to contain components of the polymerase active site. We succeeded in finding these three conserved motifs in polymerase III as well. However, none of the amino acid substitutions responsible for the antimutator phenotype occurred at these sites. This and other observations suggest that the effect of these mutations may be exerted indirectly through effects on polymerase conformation and/or DNA/polymerase interactions.

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