Conjugational Hyperrecombination Achieved by Derepressing the LexA Regulon, Altering the Properties of RecA Protein and Inactivating Mismatch Repair in Escherichia coli K-12

Abstract The frequency of recombinational exchanges (FRE) that disrupt co-inheritance of transferred donor markers in Escherichia coli Hfr by F- crosses differs by up to a factor of two depending on physiological factors and culture conditions. Under standard conditions we found FRE to be 5.01 ± 0.43 exchanges per 100-min units of DNA length for wild-type strains of the AB1157 line. Using these conditions we showed a cumulative effect of various mutations on FRE. Constitutive SOS expression by lexA gene inactivation (lexA71::Tn5) and recA gene mutation (recA730) showed, respectively, ∼4- and 7-fold increases of FRE. The double lexA71 recA730 combination gave an ∼17-fold increase in FRE. Addition of mutS215::Tn10, inactivating the mismatch repair system, to the double lexA recA mutant increased FRE to ∼26-fold above wild-type FRE. Finally, we showed that another recA mutation produced as much SOS expression as recA730 but increased FRE only 3-fold. We conclude that three factors contribute to normally low FRE under standard conditions: repression of the LexA regulon, the properties of wild-type RecA protein, and a functioning MutSHL mismatch repair system. We discuss mechanisms by which the lexA, recA, and mutS mutations may elevate FRE cumulatively to obtain hyperrecombination.

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Saturation of DNA Mismatch Repair and Error Catastrophe by a Base Analogue in Escherichia coli

Genetics ◽

10.1093/genetics/161.4.1363 ◽

2002 ◽

Vol 161 (4) ◽

pp. 1363-1371

Author(s):

Kazuo Negishi ◽

David Loakes ◽

Roel M Schaaper

Keyword(s):

Escherichia Coli ◽

Mismatch Repair ◽

Dna Mismatch Repair ◽

Repair System ◽

Mutagenic Action ◽

Wild Type ◽

Dna Mismatch ◽

Cell Counts ◽

Error Catastrophe ◽

Mismatch Repair System

Abstract Deoxyribosyl-dihydropyrimido[4,5-c][1,2]oxazin-7-one (dP) is a potent mutagenic deoxycytidine-derived base analogue capable of pairing with both A and G, thereby causing G · C → A · T and A · T → G · C transition mutations. We have found that the Escherichia coli DNA mismatch-repair system can protect cells against this mutagenic action. At a low dose, dP is much more mutagenic in mismatch-repair-defective mutH, mutL, and mutS strains than in a wild-type strain. At higher doses, the difference between the wild-type and the mutator strains becomes small, indicative of saturation of mismatch repair. Introduction of a plasmid containing the E. coli mutL+ gene significantly reduces dP-induced mutagenesis. Together, the results indicate that the mismatch-repair system can remove dP-induced replication errors, but that its capacity to remove dP-containing mismatches can readily be saturated. When cells are cultured at high dP concentration, mutant frequencies reach exceptionally high levels and viable cell counts are reduced. The observations are consistent with a hypothesis in which dP-induced cell killing and growth impairment result from excess mutations (error catastrophe), as previously observed spontaneously in proofreading-deficient mutD (dnaQ) strains.

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Specificity of the Dam-directed mismatch repair system of Escherichia coli K-12

Gene ◽

10.1016/0378-1119(88)90275-2 ◽

1988 ◽

Vol 74 (1) ◽

pp. 157-158 ◽

Cited By ~ 5

Author(s):

M. Carraway ◽

C. Rewinski ◽

T.-H. Wu ◽

M.G. Marinus

Keyword(s):

Escherichia Coli ◽

Mismatch Repair ◽

Repair System ◽

Mismatch Repair System ◽

K 12

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Repair of single- and multiple-substitution mismatches during recombination in Streptococcus pneumoniae.

Genetics ◽

10.1093/genetics/121.1.29 ◽

1989 ◽

Vol 121 (1) ◽

pp. 29-36 ◽

Cited By ~ 1

Author(s):

A M Gasc ◽

A M Sicard ◽

J P Claverys

Keyword(s):

Escherichia Coli ◽

Streptococcus Pneumoniae ◽

Mismatch Repair ◽

Base Composition ◽

Repair System ◽

Wild Type ◽

Simple Correlation ◽

Repair Efficiency ◽

Mismatch Repair System ◽

Multiple Substitution

Abstract The use as genetic markers, during transformation of Streptococcus pneumoniae, of 19 sequences differing from wild type, located throughout the amiA locus, enabled us to examine the fate of 24 single- and 11 multiple-mismatches during recombination. Tentative mismatch ranking as a function of decreasing repair efficiency by the Hex mismatch repair system is G/T = A/C = G/G (maximum repair: 90-95%) greater than C/T (mostly 75 to 90% repair) greater than A/A (from 50 to 90% repair) greater than T/T (50-65% repair) greater than A/G (from 0 to 20% repair) greater than C/C. No indication of correction of the latter has been obtained. Over the limited number of samples examined, we observed no influence of the base composition of the surrounding sequence on correction efficiency for both transition mismatches and for G/G and C/C. Variations in the surrounding sequence affect repair of A/G and C/T, and, even more strongly, of A/A and T/T. No simple correlation to the G:C content of the surrounding sequence is apparent from our results, in contrast to the conclusion drawn for the Mut mismatch repair system of Escherichia coli. Examination of the fate of multiple mismatches suggests that C/C may sometimes impede recognition of otherwise corrected mismatches.

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2-Aminopurine Allows Interspecies Recombination by a Reversible Inactivation of the Escherichia coli Mismatch Repair System

Journal of Bacteriology ◽

10.1128/jb.185.4.1459-1461.2003 ◽

2003 ◽

Vol 185 (4) ◽

pp. 1459-1461 ◽

Cited By ~ 9

Author(s):

Ivan Matic ◽

Ana Babic ◽

Miroslav Radman

Keyword(s):

Escherichia Coli ◽

Mismatch Repair ◽

Fold Increase ◽

Repair System ◽

Reversible Inactivation ◽

Dna Mismatch ◽

Repair Deficiency ◽

Serovar Typhimurium ◽

Mismatch Repair System ◽

Dna Mismatch Repair Deficiency

ABSTRACT 2-Aminopurine treatment of Escherichia coli induces a reversible phenotype of DNA mismatch repair deficiency. This transient phenotype results in a 300-fold increase in the frequency of interspecies conjugational recombination with a Salmonella enterica serovar Typhimurium Hfr donor. This method can be used for the generation of biodiversity by allowing recombination between diverged genes and genomes.

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Mutants with Temperature-Sensitive Defects in the Escherichia coli Mismatch Repair System: Sensitivity to Mispairs Generated In Vivo

Journal of Bacteriology ◽

10.1128/jb.187.3.840-846.2005 ◽

2005 ◽

Vol 187 (3) ◽

pp. 840-846 ◽

Cited By ~ 6

Author(s):

Esther S. Hong ◽

Annie Yeung ◽

Pauline Funchain ◽

Malgorzata M. Slupska ◽

Jeffrey H. Miller

Keyword(s):

Escherichia Coli ◽

Mismatch Repair ◽

Temperature Sensitive ◽

Repair System ◽

Wild Type ◽

System Sensitivity ◽

Large Numbers ◽

Mismatch Repair System ◽

Homeologous Recombination

ABSTRACT We have used direct selections to generate large numbers of mutants of Escherichia coli defective in the mismatch repair system and have screened these to identify mutants with temperature-sensitive defects. We detected and sequenced mutations that give rise to temperature-sensitive MutS, MutL, and MutH proteins. One mutation, mutS60, results in almost normal levels of spontaneous mutations at 37°C but above this temperature gives rise to higher and higher levels of mutations, reaching the level of null mutations in mutS at 43°C. However, at 37°C the MutS60 protein can be much more easily titrated by mispairs than the wild-type MutS, as evidenced by the impaired ability to block homeologous recombination in interspecies crosses and the increased levels of mutations from weak mutator alleles of mutD (dnaQ), mutC, and ndk. Strains with mutS60 can detect mispairs generated during replication that lead to mutation with much greater sensitivity than wild-type strains. The findings with ndk, lacking nucleotide diphosphate kinase, are striking. An ndk mutS60 strain yields four to five times the level of mutations seen in a full knockout of mutS. These results pose the question of whether similar altered Msh2 proteins result from presumed polymorphisms detected in tumor lines. The role of allele interactions in human disease susceptibility is discussed.

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Antagonism of Ultraviolet-Light Mutagenesis by the Methyl-Directed Mismatch-Repair System of Escherichia coli

Genetics ◽

10.1093/genetics/154.2.503 ◽

2000 ◽

Vol 154 (2) ◽

pp. 503-512 ◽

Cited By ~ 1

Author(s):

Hongbo Liu ◽

Stephen R Hewitt ◽

John B Hays

Keyword(s):

Escherichia Coli ◽

Mismatch Repair ◽

Excision Repair ◽

Spontaneous Mutation ◽

Repair System ◽

Uv Mutagenesis ◽

Repair Protein ◽

Mismatch Repair System

Abstract Previous studies have demonstrated that the Escherichia coli MutHLS mismatch-repair system can process UV-irradiated DNA in vivo and that the human MSH2·MSH6 mismatch-repair protein binds more strongly in vitro to photoproduct/base mismatches than to “matched” photoproducts in DNA. We tested the hypothesis that mismatch repair directed against incorrect bases opposite photoproducts might reduce UV mutagenesis, using two alleles at E. coli lacZ codon 461, which revert, respectively, via CCC → CTC and CTT → CTC transitions. F′ lacZ targets were mated from mut+ donors into mutH, mutL, or mutS recipients, once cells were at substantial densities, to minimize spontaneous mutation prior to irradiation. In umu+ mut+ recipients, a range of UV fluences induced lac+ revertant frequencies of 4–25 × 10−8; these frequencies were consistently 2-fold higher in mutH, mutL, or mutS recipients. Since this effect on mutation frequency was unaltered by an Mfd− defect, it appears not to involve transcription-coupled excision repair. In mut+ umuC122::Tn5 bacteria, UV mutagenesis (at 60 J/m2) was very low, but mutH or mutL or mutS mutations increased reversion of both lacZ alleles roughly 25-fold, to 5–10 × 10−8. Thus, at UV doses too low to induce SOS functions, such as Umu2′D, most incorrect bases opposite occasional photoproducts may be removed by mismatch repair, whereas in heavily irradiated (SOS-induced) cells, mismatch repair may only correct some photoproduct/base mismatches, so UV mutagenesis remains substantial.

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Frameshift lesions induced by oxazolopyridocarbazoles are recognized by the mismatch repair system in Escherichia coli

Mutation Research/DNA Repair Reports ◽

10.1016/0167-8817(88)90037-5 ◽

1988 ◽

Vol 193 (3) ◽

pp. 269-273 ◽

Cited By ~ 3

Author(s):

Brigitte René ◽

Christian Auclair ◽

Claude Paoletti

Keyword(s):

Escherichia Coli ◽

Mismatch Repair ◽

Repair System ◽

Mismatch Repair System

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Frameshift intermediates in homopolymer runs are removed efficiently by yeast mismatch repair proteins.

Molecular and Cellular Biology ◽

10.1128/mcb.17.5.2844 ◽

1997 ◽

Vol 17 (5) ◽

pp. 2844-2850 ◽

Cited By ~ 72

Author(s):

C N Greene ◽

S Jinks-Robertson

Keyword(s):

Mismatch Repair ◽

Wild Type Strain ◽

Frameshift Mutation ◽

Protein A ◽

Repair System ◽

Wild Type ◽

Base Pairs ◽

Replication Errors ◽

Mismatch Repair System ◽

Mismatch Repair Proteins

A change in the number of base pairs within a coding sequence can result in a frameshift mutation, which almost invariably eliminates the function of the encoded protein. A frameshift reversion assay with Saccharomyces cerevisiae that can be used to examine the types of insertions and deletions that are generated during DNA replication, as well as the editing functions that remove such replication errors, has been developed. Reversion spectra have been obtained in a wild-type strain and in strains defective for defined components of the postreplicative mismatch repair system (msh2, msh3, msh6, msh3 msh6, pms1, and mih1 mutants). Comparison of the spectra reveals that yeast mismatch repair proteins preferentially remove frameshift intermediates that arise in homopolymer tracts and indicates that some of the proteins have distinct substrate or context specificities.

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Human mismatch repair system corrects errors produced during lagging strand replication more effectively

10.1101/045278 ◽

2016 ◽

Cited By ~ 1

Author(s):

Maria Andrianova ◽

Georgii A Bazykin ◽

Sergey Nikolaev ◽

Vladimir Seplyarskiy

Keyword(s):

Mismatch Repair ◽

Mutation Rates ◽

Repair System ◽

Wild Type ◽

Strand Asymmetry ◽

Exonuclease Domain ◽

Mismatch Repair System ◽

Dna Strands ◽

Leading Strand ◽

Lagging Strand

Mismatch repair (MMR) is one of the main systems maintaining fidelity of replication. Different effectiveness in correction of errors produced during replication of the leading and the lagging DNA strands was reported in yeast, but this effect is poorly studied in humans. Here, we use MMR-deficient (MSI) and MMR-proficient (MSS) cancer samples to investigate properties of the human MMR. MSI, but not MSS, cancers demonstrate unequal mutation rates between the leading and the lagging strands. The direction of strand asymmetry in MSI cancers matches that observed in cancers with mutated exonuclease domain of polymerase δ, indicating that polymerase δ contributes more mutations than its leading-strand counterpart, polymerase ε. As polymerase δ primarily synthesizes DNA during the lagging strand replication, this implies that mutations produced in wild type cells during lagging strand replication are repaired by the MMR ~3 times more effectively, compared to those produced on the leading strand.

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