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Role of Escherichia coli DNA Polymerase IV in In Vivo Replication Fidelity

Institute of Biochemistry and Biophysics, Polish Academy of Sciences, 02 106 Warsaw, Poland,¹ Laboratory of Molecular Genetics, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina 27709²

Received 31 January 2004/ Accepted 7 April 2004

	ABSTRACT

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We have investigated whether DNA polymerase IV (Pol IV; the dinB gene product) contributes to the error rate of chromosomal DNA replication in Escherichia coli. We compared mutation frequencies in mismatch repair-defective strains that were either dinB positive or dinB deficient, using a series of mutational markers, including lac targets in both orientations on the chromosome. Virtually no contribution of Pol IV to the chromosomal mutation rate was observed. On the other hand, a significant effect of dinB was observed for reversion of a lac allele when the lac gene resided on an F'(pro-lac) episome.

	TEXT

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Several mechanisms control the fidelity of the DNA replication process. These include correct base selection by the DNA polymerase, removal of base insertion errors by 3'-exonucleolytic proofreading, and correction by DNA mismatch repair (29). In Escherichia coli, base selection and proofreading are performed by the DNA polymerase III (Pol III) holoenzyme, the enzyme that replicates the bacterial chromosome. It is generally considered a highly accurate enzyme (29). Mismatch repair is performed by the mutHLS mismatch repair system (17). In combination, these three processes yield an error rate of 10^–9 to 10^–11 error per base pair replicated per cell division (6, 29).

In addition to Pol III, E. coli possesses four other DNA polymerases, Pol I, Pol II, Pol IV, and Pol V, whose precise functions are still being defined. Pol IV and Pol V belong to the recently described Y family of DNA polymerases (H. Ohmori, E. C. Friedberg, R. P. P. Fuchs, M. F. Goodman, F. Hanaoka, D. Hinkle, T. A. Kunkel, C. W. Lawrence, Z. Livneh, T. Nohmi, L. Prakash, S. Prakash, T. Todo, G. C. Walker, Z. Wang, and R. Woodgate, Letter, Mol. Cell 8:7-8, 2001). Pol IV and Pol V are generally considered low-fidelity DNA polymerases in view of their lack of proofreading activity and their high in vitro error rates (14, 37). Both enzymes are inducible as part of the SOS regulon, and under SOS-induced conditions they function in lesion bypass and mutagenesis (3, 14, 21, 22, 28, 33, 37, 39).

In contrast to Pol V, which is tightly controlled and essentially not present outside of SOS-induced conditions, Pol IV has a relatively high basal expression level (21), an estimated 250 molecules of Pol IV per cell (20) compared to about 30 molecules of Pol III and much less of the complete Pol III holoenzyme (25). It has been proposed (14) that in certain instances, such as at blocked DNA replication forks, Pol IV might gain access to the replication fork and perform remedial DNA synthesis. Thus, its abundance and potential access to the replication point raise the question of whether this low-fidelity enzyme may contribute to the replication error rate and spontaneous mutagenesis. Consistent with this potential role, overexpression of Pol IV was shown to result in a mutator phenotype (20, 40). Another instance where Pol IV has been implicated is mutagenesis in nondividing cells (adaptive or stationary-phase mutagenesis) (9). Adaptive mutations are routinely assessed through reversion of the lacI33lacZ frameshift allele residing on an F' episome (9). Loss of Pol IV significantly diminishes these mutations, implicating Pol IV in their production (9, 26, 38).

In this report we examine the possible role of Pol IV in contributing to the chromosomal mutation rate in dividing cells. We did this by carefully analyzing the level and specificity of spontaneous mutation in mismatch repair-defective mutL strains with or without Pol IV present. Mismatch repair-defective strains are most suitable for this purpose, as their mutation rates most directly reflect the error rate of ongoing DNA replication. We used a variety of mutational detection systems, including a system developed previously in our laboratory that permits measurement of reversion of a series of lacZ alleles residing in two orientations in the E. coli chromosome with respect to the direction of replication (7), causing lac sequences to be replicated either as a leading or a lagging strand during chromosomal replication. Thus, in addition to assessing the general role of Pol IV by comparing din⁺ to dinB strains, it may be possible to assess whether Pol IV might work differentially in one of the two strands, specifically. To inactivate Pol IV, we used the dinB::kan allele, which also includes a partial deletion of the yafN gene (21).

Forward mutagenesis to rifampin and nalidixic acid resistance and reversion of the trpE9777 frameshift allele. We first tested a series of chromosomal markers by using strain NR13145 [ara thi (pro-lac) mutL::Tn10 trpE9777] and its dinB::kan derivative, strain NR13146. The strains are derivatives of KA796 (32) into which the trpE9777 (30, 34), mutL::Tn10 (31), and dinB::kan (21) alleles were introduced by P1 transduction. The strains allow measurement of trpE9777 frameshift reversion as well as forward mutagenesis to rifampin resistance (Rif^r) and nalidixic acid resistance (Nal^r). The trpE9777 allele contains an extra A · T base pair added to a run of five A · T base pairs (M. J. Bronson and C. Yanofsky, Letter, J. Mol. Biol. 88:913-915, 1974), and reversion occurs by loss of the extra pair (34). The data shown in Fig. 1 indicate that there were no significant differences in mutability between the dinB-positive and dinB-deficient strains for this marker. Likewise, no effects of dinB were observed for the Rif^r or Nal^r forward-mutagenesis systems, which allow scoring of base substitution mutagenesis at multiple sites in the rpoB or gyrA gene, respectively (11, 41). These experiments were performed multiple times, and no significant differences between dinB and dinB⁺ strains were observed in any of them (see Fig. 1).

View larger version (41K): [in this window] [in a new window]   FIG. 1. Effect of dinB deletion on frequencies of mutants (per 108 cells) of mismatch repair-defective mutL strains. Light gray bars, dinB positive; dark gray bars, dinB deficient. The numbers above each bar indicate the average frequencies of mutants calculated for 30 independent cultures. This experiment was performed a total of four times with similar results. In no case was a significant difference for the dinB-to-dinB+ comparison found (P > 0.5). Error bars represent standard errors of the means.

The strains used have been described previously (7, 12, 13). They are mutL::Tn5 derivatives of MC4100 (lac) carrying a series of defined lac alleles (4, 5) in the attachment site and having either a dinB⁺ or dinB::kan genotype. For the lac alleles, we used four base substitution markers and four frameshift markers. The base substitution markers (5) were two transitions (G · CA · T and A · TG · C) and two transversions (G · CT · A and A · TT · A). The frameshift markers (4) were two (+1) frameshifts [addition of G · C to a (G · C)₆ run or A · T to an (A · T)₆ run] and two (–1) frameshifts [loss of G · C from (G · C)₆ or A · T from (A · T)₇].

The data in Fig. 2 show that, as before (7, 12, 13), significantly different frequencies of mutants were observed when the effect of orientation (R versus L) on all four base substitution alleles and three of the four frameshift alleles in the dinB⁺ control strains was tested. However, introduction of the dinB allele did not significantly affect the level of any of the observed mutations, regardless of the gene orientation (with one minor exception described below). The lack of differences is statistically significant (see legend to Fig. 2) and was observed in numerous repeated experiments (4 to 10 repeats for each lac allele). In the case of the –1G frameshift event only, a small but repeatable difference was observed between the dinB⁺ and dinB strains. In each repeated experiment with this allele, we observed a very moderate (20%) but consistent decrease in the mutability of the dinB derivative carrying the L-oriented lac operon. No difference was observed for the corresponding R-oriented strain. This suggests that for this lacZ allele, Pol IV may play a minor, strand-specific role.

View larger version (37K): [in this window] [in a new window]   FIG. 2. Frequencies of base substitution or frameshift mutants (Lac+ revertants per 108 cells) of dinB+ and dinB pairs of strains containing the lac operon in two orientations. The strains were mismatch repair defective (mutL). The base substitution or frameshift measured in each case is indicated above the panel. Light gray bars indicate frequencies of mutants of the dinB+ strains; dark gray bars indicate frequencies of mutants of the dinB-deficient strains. L and R indicate the transcription orientation of the lac operon (7). The numbers above the bars are the average frequencies of mutants calculated for 30 independent cultures, and error bars represent standard errors of the means. For all of these experiments, the observed differences in lac reversion frequency between dinB+ and dinB pairs of strains are not statistically significant (P > 0.5), with the exception of a small (20%) effect for the –1G allele in the L orientation (P < 0.05).

To complement our chromosomal experiments, we also conducted an experiment with a set of strains containing F'(pro-lac). We assayed for two chromosomal markers (Rif^r and trpE9777 reversion) and one F'(pro-lac)-contained marker, the lacZ gene from strain CC104, which permits measurement of G · CT · A transversions (5). The strains used were as described above for Fig. 1, except that the relevant F' (either dinB positive or with the dinB::kan deletion) was introduced by conjugation. The data in Table 1 show the results obtained for four different dinB configurations: fully positive (gene present on both chromosome and F'), semideficient (gene absent on either F' or the chromosome), and fully deficient. The data show that the frequencies for the two chromosomal markers are unaffected or are little affected by the dinB copy number, whereas the episomal G · CT · A marker is significantly affected. In four independent experiments, the average reductions due to the dinB defect were 1.9-fold (loss of the F' copy), 1.3-fold (loss of the chromosomal copy), and 3.0-fold (loss of both copies). This result indicates that, in this system, Pol IV contributes significantly (70%) to the production of G · CT · A transversions. The mutants on the Lac plates were counted after about 40 to 45 h of incubation, when Lac⁺ revertants first appeared. Thus, even though the lac G · CT · A transversion allele has been shown to produce (modest amounts of) "adaptive" mutants upon prolonged incubation on the plate (16, 23), the observed mutants must be considered preexisting (growth dependent). Similar results were obtained in this experiment when the dinB::kan allele was replaced by the nonpolar dinB::zeo allele (2; data not shown).

Our experiments did show a small (20%) but consistent role for Pol IV in the reversion of the –1G frameshift lacZ allele, but only when the lacZ gene was in the L orientation (Fig. 2). This result suggests that Pol IV does contribute to errors in this configuration. Due to the complexity of frameshift mutagenesis (1), whether this role is an involvement in leading- or lagging-strand replication cannot be readily deduced. However, overexpression of Pol V preferentially increased base substitution mutagenesis in the lagging strand, presumably because of easier access (24). Preliminary data suggest that the same may be true for the mutator effect resulting from Pol IV overexpression (unpublished data). Overall, based on multiple repeats of the experiments shown in Fig. 2, we estimate that the 20% effect observed for the case of the –1G lacZ allele represents a general upper limit for the contribution of Pol IV in any of the other chromosomal tests reported here.

In contrast to the case with the chromosomal mutations, our data indicate that Pol IV can play a significant role in mutation production on the F'(pro-lac) episome, even in growing cells (Table 1). Presumably, one factor contributing to this mutation production is the increased dinB gene dosage in this experimental setting, as the F' carries an additional copy of the gene and multiple F' copies may be present. Overproduction of Pol IV has been demonstrated to lead to a mutator phenotype (20, 41). Interestingly, and consistent with the data of Kim et al. (21), who noted that the episomal dinB copy produced more Pol IV protein than the chromosomal copy, we noticed that the deletion of dinB from the episome decreased the frequency of mutants more than the deletion of dinB from the chromosome (1.3- versus 1.9-fold; average result of four experiments).

Interestingly, increased dinB copy number did not significantly increase the frequency of chromosomal Rif^r mutations or trpE9777 frameshift reversions (Table 1). This finding suggests that location of the target gene on the F' itself might also be necessary for enhanced mutagenesis. A rigorous demonstration of this will require comparison of the lacZ target genes on the chromosome and F' under the various dinB gene dosage conditions. In the meantime, one might speculate that the same principles that underlie the production of growth-independent mutations (which are to a large extent dinB dependent) are also relevant to the growth-dependent mutations observed here. The duplications and amplifications of episomal lac sequences that have been shown to be prerequisites for the production of mutations under nongrowing conditions (19) are, in fact, produced during the preceding growth phase (19). These amplified sequences may include both lac and dinB (19, 35). Therefore, even in growing cells, conditions may be favorable for preferential mutagenesis of episomal lac sequences in a dinB-dependent manner. Although experiments reported here used the (dinB-yafN) allele, for which polar effects on the yaf genes have been suggested to contribute to certain mutational end points (26, 27), we obtained identical results with the nonpolar dinB::zeo allele (2; data not shown). Thus, we conclude that the mutator effect of Pol IV on F'(pro-lac) is due to Pol IV and not to other members of the yaf operon.

The question of the role of Pol IV in replication fidelity has been addressed before. Strauss et al. (36), using dnaE mutator strains containing an impaired Pol III, noted that about 75% of mutations in this background were dinB dependent, based on measurements of either lac reversion on F' or chromosomal Rif^r mutations. Interestingly, they also noted a corresponding 1.5- to 3-fold dinB-dependent reduction in the dnaE⁺ control strain, implying a role for Pol IV in creating these mutations. However, the effect of the dinB::kan allele in the control strain was limited to the mismatch repair-proficient background. No effect was observed in the mismatch repair-deficient mutS background, in which replication errors are more directly viewed. Experiments in our laboratory with mut⁺ derivatives of the strains shown in Fig. 2 have not revealed any effect of dinB when chromosomal Rif^r mutations or chromosomal G · CT · A or –1G lac reversions are being scored (data not shown). This discrepancy remains to be explored.

McKenzie et al. (26) demonstrated the lack of an effect of the dinB10 allele on the mutability of a series of chromosomal markers. These experiments were performed in the mismatch repair-proficient background, and their results are therefore not directly comparable to those of our experiments, which focus on the production of replication errors. Nevertheless, the absence of an effect in both studies is consistent with the lack of a role for Pol IV in chromosomal replication fidelity. With regard to the effect of dinB on episomal genes, the experiments of McKenzie et al. indicated a lack of effect of dinB10 on the lacI33lacZ allele (26), a result that appears to contradict our results with the episomal lac G · CT · A transversion (Table 1). However, a reasonable explanation may be that DNA mismatch repair is efficient in removing most or all of the Pol IV-mediated frameshift revertants of lacI33lacZ, masking the effect of Pol IV on replication errors. Efficient correction of the lacI33lacZ revertants has been demonstrated (8, 9, 18). In a second study, McKenzie et al. (27) made a distinction between the nonpolar dinB alleles, such as dinB10, and the polar alleles, such as dinB::kan, which exerts a polar effect on the distal members of the dinB-yafNOP operon. An effect (approximately twofold) was observed on lacI33lacZ reversion with the polar dinB::kan allele but not with the nonpolar alleles (27), leading the authors to conclude that the distal members of the operon might be involved. In our study, we observed an effect on the episomal lacZ G · CT · A marker with both the polar dinB::kan allele (Table 1) and the nonpolar dinB::zeo allele, suggesting that only Pol IV is involved. These differences may reflect both the action of mismatch repair, which may dramatically influence the extent to which replication errors can be observed, and any mechanistic differences in the genesis of lacI33lacZ frameshifts and lacZ G · CT · A transversions. This issue requires further study.

In summary, no evidence has been found for a significant contribution of Pol IV to chromosomal mutagenesis in growing cells, although episomal mutagenesis on F'(pro-lac) may be enhanced by Pol IV action.

ADDENDUM IN PROOF Recently, Wolff et al. (E. Wolff, M. Kim, K. Hu, H. Yang, and J. H. Miller, J. Bacteriol 186:2900-2905, 2004), based on an analysis of the spectral fingerprint of DNA polymerase IV-induced mutations, also concluded that Pol IV does not contribute significantly to mutations occurring during exponential growth.

	ACKNOWLEDGMENTS

 
We thank K. Bebenek and S. McCulloch of the National Institute of Environmental Health Sciences for careful review of this paper. We thank Takehiko Nohmi for providing dinB::kan strain YG7207 and Roger Woodgate for providing the dinB::zeo strain AR30.

This research was supported by grant 3PO4A04223 from the Polish Ministry of Scientific Research and Information Technology, State Committee for Scientific Research. D.G. was the recipient of a fellowship from the Kosciuszko Foundation.

	FOOTNOTES

 
* Corresponding author. Mailing address: Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego. 5A, 02106 Warsaw, Poland. Phone: (48) 22-6584734. Fax: (48) 39-121623. E-mail: iwonaf{at}ibb.waw.pl.

	REFERENCES

Top Abstract Text References

 

1. Bebenek, K., and T. A. Kunkel. 2000. Streisinger revisited: DNA synthesis errors mediated by substrate misalignments. Cold Spring Harbor Symp. Quant. Biol. 65:81-91.
2. Borden, A., P. I. O'Grady, D. Vandewiele, A. R. Fernández de Henestrosa, C. W. Lawrence, and R. Woodgate. 2002. Escherichia coli DNA polymerase III can replicate efficiently past a T-T cis-syn cyclobutane dimer if DNA polymerase V and the 3' to 5' exonuclease proofreading function encoded by dnaQ are inactivated. J. Bacteriol. 184:2674-2681.[Abstract/Free Full Text]
3. Brotcorne-Lannoye, A., and G. Maenhaut-Michel. 1986. Role of RecA protein in untargeted UV mutagenesis of bacteriophage : evidence for the requirement for the dinB gene. Proc. Natl. Acad. Sci. USA 83:3904-3908.[Abstract/Free Full Text]
4. Cupples, C. G., M. Cabrera, C. Cruz, and J. H. Miller. 1990. A set of lacZ mutations in Escherichia coli that allow rapid detection of specific frameshift mutations. Genetics 125:275-280.[Abstract]
5. Cupples, C. G., and J. H. Miller. 1989. A set of lacZ mutations in Escherichia coli that allow rapid detection of each of the six base substitutions. Proc. Natl. Acad. Sci. USA 86:5345-5349.[Abstract/Free Full Text]
6. Drake, J. W. 1991. A constant rate of spontaneous mutation in DNA-based microbes. Proc. Natl. Acad. Sci. USA 88:7160-7164.[Abstract/Free Full Text]
7. Fijalkowska, I. J., P. Jonczyk, M. Maliszewska-Tkaczyk, M. Bialoskorska, and R. M. Schaaper. 1998. Unequal fidelity of leading and lagging strand DNA replication on the Escherichia coli chromosome. Proc. Natl. Acad. Sci. USA 95:10020-10025.[Abstract/Free Full Text]
8. Foster, P. L. 1999. Are adaptive mutations due to a decline in mismatch repair? The evidence is lacking. Mutat. Res. 436:179-184.[CrossRef][Medline]
9. Foster, P. L. 2000. Adaptive mutation in Escherichia coli. Cold Spring Harbor Symp. Quant. Biol. 65:21-29.
10. Frame, R., and J. O. Bishop. 1971. The number of sex-factors per chromosome in Escherichia coli. Biochem. J. 121:93-103.[Medline]
11. Garibyan, L., T. Huang, M. Kim, E. Wolff, A. Nguyen, T. Nguyen, A. Diep, K. Hu, A. Iverson, H. Yang, and J. H. Miller. 2003. Use of the rpoB gene to determine the specificity of base substitution mutations on the Escherichia coli chromosome. DNA Repair 2:593-608.[CrossRef][Medline]
12. Gawel, D., M. Bialoskorska, P. Jonczyk, R. M. Schaaper, and I. J. Fijalkowska. 2002. Asymmetry of frameshift mutagenesis during leading and lagging strand replication in E. coli. Mutat. Res. 501:129-136.[Medline]
13. Gawel, D., M. Maliszewska-Tkaczyk, P. Jonczyk, R. M. Schaaper, and I. J. Fijalkowska. 2002. Lack of strand bias in UV-induced mutagenesis in Escherichia coli. J. Bacteriol. 184:4449-4454.[Abstract/Free Full Text]
14. Goodman, M. F. 2002. Error-prone repair DNA polymerases in prokaryotes and eukaryotes. Annu. Rev. Biochem. 71:17-50.[CrossRef][Medline]
15. Gordon, G. S., D. Sitnikov, C. D. Webb, A. Teleman, and A. Straight. 1997. Chromosome and low copy plasmid segregation in E. coli: visual evidence for distinct mechanisms. Cell 90:1113-1121.[CrossRef][Medline]
16. Hall, B. G. 1991. Spectrum of mutations that occur under selective and non-selective conditions in E. coli. Genetica 84:73-76.[CrossRef][Medline]
17. Harfe, B. D., and S. Jinks-Robertson. 2000. DNA mismatch repair and genetic instability. Annu. Rev. Genet. 34:359-399.[CrossRef][Medline]
18. Harris, R. S., H. J. Bull, and S. M. Rosenberg. 1997. A direct role for DNA polymerase III in adaptive reversion of a frameshift mutation in Escherichia coli. Mutat. Res. 375:19-24.[Medline]
19. Hendrickson, H., E. S. Slechta, U. Bergthorsson, D. I. Andersson, and J. R. Roth. 2002. Amplification-mutagenesis: evidence that "directed" adaptive mutation and general hypermutability result from growth with a selected gene amplification. Proc. Natl. Acad. Sci. USA 99:2164-2169.[Abstract/Free Full Text]
20. Kim, S.-R., G. Maenhaut-Michel, M. Yamada, Y. Yamamoto, K. Matsui, T. Sofuni, T. Nohmi, and H. Ohmori. 1997. Multiple pathways for SOS-induced mutagenesis in Escherichia coli: an SOS gene product (DinB/P) enhances frameshift mutations in the absence of any exogenous agents that damage DNA. Proc. Natl. Acad. Sci. USA 94:13792-13797.[Abstract/Free Full Text]
21. Kim, S.-R., K. Matsui, M. Yamada, P. Gruz, and T. Nohmi. 2001. Roles of chromosomal and episomal dinB genes encoding pol IV in targeted and untargeted mutagenesis in Escherichia coli. Mol. Genet. Genomics 266:207-215.[CrossRef][Medline]
22. Lenne-Samuel, N., R. Janel-Bintz, A. Kolbanovskiy, N. E. Geacintov, and R. P. P. Fuchs. 2000. The processing of a benzo(a)pyrene adduct into a frameshift or a base substitution mutation requires a different set of genes in Escherichia coli. Mol. Microbiol. 38:299-307.[CrossRef][Medline]
23. Mackay, W. J., S. Han, and L. D. Samson. 1994. DNA alkylation repair limits spontaneous base substitution mutations in Escherichia coli. J. Bacteriol. 176:3224-3230.[Abstract/Free Full Text]
24. Maliszewska-Tkaczyk, M., P. Jonczyk, M. Bialoskorska, R. M. Schaaper, and I. J. Fijalkowska. 2000. SOS mutator activity: unequal mutagenesis on leading and lagging strands. Proc. Natl. Acad. Sci. USA 97:12678-12683.[Abstract/Free Full Text]
25. McHenry, C., and A. Kornberg. 1977. DNA polymerase III holoenzyme of Escherichia coli. Purification and resolution into subunits. J. Biol. Chem. 252:6478-6484.[Abstract/Free Full Text]
26. McKenzie, G. J., P. L. Lee, M.-J. Lombardo, P. J. Hastings, and S. M. Rosenberg. 2001. SOS mutator DNA polymerase IV functions in adaptive mutation and not adaptive amplification. Mol. Cell 7:571-579. (Erratum, 7:1119.)[CrossRef][Medline]
27. McKenzie, G. J., D. B. Magner, P. L. Lee, and S. M. Rosenberg. 2003. The dinB operon and spontaneous mutation in Escherichia coli. J. Bacteriol. 185:3972-3977.[Abstract/Free Full Text]
28. Napolitano, R., R. Janel-Bintz, J. Wagner, and R. P. P. Fuchs. 2000. All three SOS-inducible DNA polymerases (Pol II, Pol IV, and Pol V) are involved in induced mutagenesis. EMBO J. 19:6259-6265.[CrossRef][Medline]
29. Schaaper, R. M. 1993. Base selection, proofreading, and mismatch repair during DNA replication in Escherichia coli. J. Biol. Chem. 268:23762-23765.[Abstract/Free Full Text]
30. Schaaper, R. M. 1993. The mutational specificity of two Escherichia coli dnaE antimutator alleles as determined from lacI mutation spectra. Genetics 134:1031-1038.[Abstract]
31. Schaaper, R. M., B. I. Bond, and R. G. Fowler. 1989. A · TC · G transversions and their prevention by the Escherichia coli mutT and mutHLS pathways. Mol. Gen. Genet. 219:256-262.[Medline]
32. Schaaper, R. M., B. N. Danforth, and B. W. Glickman. 1985. Rapid repeated cloning of mutant lac repressor genes. Gene 39:181-189.[CrossRef][Medline]
33. Shen, X., J. M. Sayer, H. Kroth, I. Ponten, M. O'Donnell, R. Woodgate, D. M. Jerina, and M. F. Goodman. 2002. Efficiency and accuracy of SOS-induced DNA polymerases replicating benzo[a]pyrene-7,8-diol 9,10-epoxide A and G adducts. J. Biol. Chem. 277:5265-5274.[Abstract/Free Full Text]
34. Siegel, E. C., and K. K. Vaccaro. 1978. The reversion of trp frameshift mutations in mut, polA, lig and dnaE mutant strains of Escherichia coli. Mutat. Res. 50:9-17.
35. Slechta, S. E., K. L. Bunny, E. Kugelberg, E. Kofoid, D. I. Andersson, and J. R. Roth. 2003. Adaptive mutation: general mutagenesis is not a programmed response to stress but results from rare coamplification of dinB with lac. Proc. Natl. Acad. Sci. USA 100:12847-12852.[Abstract/Free Full Text]
36. Strauss, B. S., R. Roberts, L. Francis, and P. Pouryazdanparast. 2000. Role of the dinB gene product in spontaneous mutation in Escherichia coli with an impaired replicative polymerase. J. Bacteriol. 182:6742-6750.[Abstract/Free Full Text]
37. Tang, M., P. Pham, X. Shen, J. S. Taylor, M. O'Donnell, R. Woodgate, and M. F. Goodman. 2000. Roles of E. coli DNA polymerases IV and V in lesion-targeted and untargeted SOS mutagenesis. Nature 404:1014-1018.[CrossRef][Medline]
38. Tompkins, J. D., J. L. Nelson, J. C. Hazel, S. L. Leugers, J. D. Stumpf, and P. L. Foster. 2003. Error-prone polymerase, DNA polymerase IV, is responsible for transient hypermutation during adaptive mutation in Escherichia coli. J. Bacteriol. 185:3469-3472.[Abstract/Free Full Text]
39. Wagner, J., P. Grúz, S. R. Kim, M. Yamada, K. Matsui, R. P. P. Fuchs, and T. Nohmi. 1999. The dinB gene encodes a novel E. coli DNA polymerase, Pol IV, involved in mutagenesis. Mol. Cell 4:281-286.[CrossRef][Medline]
40. Wagner, J., and T. Nohmi. 2000. Escherichia coli DNA polymerase IV mutator activity: genetic requirements and mutational specificity. J. Bacteriol. 182:4587-4595.[Abstract/Free Full Text]
41. Yoshida, H., M. Bogaki, M. Nakamura, and S. Nakamura. 1990. Quinolone resistance-determining region in the DNA gyrase gyrA gene of Escherichia coli. Antimicrob. Agents Chemother. 34:1271-1272.[Abstract/Free Full Text]

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• Kuban, W., Banach-Orlowska, M., Bialoskorska, M., Lipowska, A., Schaaper, R. M., Jonczyk, P., Fijalkowska, I. J. (2005). Mutator Phenotype Resulting from DNA Polymerase IV Overproduction in Escherichia coli: Preferential Mutagenesis on the Lagging Strand. J. Bacteriol. 187: 6862-6866 [Abstract] [Full Text]  
• Layton, J. C., Foster, P. L. (2005). Error-Prone DNA Polymerase IV Is Regulated by the Heat Shock Chaperone GroE in Escherichia coli. J. Bacteriol. 187: 449-457 [Abstract] [Full Text]  

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