51
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Sweasy JB, Lauper JM, Eckert KA. DNA polymerases and human diseases. Radiat Res 2006; 166:693-714. [PMID: 17067213 DOI: 10.1667/rr0706.1] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2006] [Accepted: 07/12/2006] [Indexed: 11/03/2022]
Abstract
DNA polymerases function in DNA replication, repair, recombination and translesion synthesis. Currently, 15 DNA polymerase genes have been identified in human cells, belonging to four distinct families. In this review, we briefly describe the biochemical activities and known cellular roles of each DNA polymerase. Our major focus is on the phenotypic consequences of mutation or ablation of individual DNA polymerase genes. We discuss phenotypes of current mouse models and altered polymerase functions and the relationship of DNA polymerase gene mutations to human cell phenotypes. Interestingly, over 120 single nucleotide polymorphisms (SNPs) have been identified in human populations that are predicted to result in nonsynonymous amino acid substitutions of DNA polymerases. We discuss the putative functional consequences of these SNPs in relation to human disease.
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Affiliation(s)
- Joann B Sweasy
- Department of Therapeutic Radiology, Yale University School of Medicine, 15 York Street, HRT 313D, P.O. Box 208040, New Haven, CT 06520-8040, USA.
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52
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Acharya N, Johnson RE, Prakash S, Prakash L. Complex formation with Rev1 enhances the proficiency of Saccharomyces cerevisiae DNA polymerase zeta for mismatch extension and for extension opposite from DNA lesions. Mol Cell Biol 2006; 26:9555-63. [PMID: 17030609 PMCID: PMC1698531 DOI: 10.1128/mcb.01671-06] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Rev1, a Y family DNA polymerase (Pol) functions together with Polzeta, a B family Pol comprised of the Rev3 catalytic subunit and Rev7 accessory subunit, in promoting translesion DNA synthesis (TLS). Extensive genetic studies with Saccharomyces cerevisiae have indicated a requirement of both Polzeta and Rev1 for damage-induced mutagenesis, implicating their involvement in mutagenic TLS. Polzeta is specifically adapted to promote the extension step of lesion bypass, as it proficiently extends primer termini opposite DNA lesions, and it is also a proficient extender of mismatched primer termini on undamaged DNAs. Since TLS through UV-induced lesions and various other DNA lesions does not depend upon the DNA-synthetic activity of Rev1, Rev1 must contribute to Polzeta-dependent TLS in a nonenzymatic way. Here, we provide evidence for the physical association of Rev1 with Polzeta and show that this binding is mediated through the C terminus of Rev1 and the polymerase domain of Rev3. Importantly, a rev1 mutant that lacks the C-terminal 72 residues which inactivate interaction with Rev3 exhibits the same high degree of UV sensitivity and defectiveness in UV-induced mutagenesis as that conferred by the rev1Delta mutation. We propose that Rev1 binding to Polzeta is indispensable for the targeting of Polzeta to the replication fork stalled at a DNA lesion. In addition to this structural role, Rev1 binding enhances the proficiency of Polzeta for the extension of mismatched primer termini on undamaged DNAs and for the extension of primer termini opposite DNA lesions.
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Affiliation(s)
- Narottam Acharya
- Sealy Center for Molecular Science, University of Texas Medical Branch at Galveston, Galveston, TX 77555-1061, USA
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53
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Collins NS, Bhattacharyya S, Lahue RS. Rev1 enhances CAG.CTG repeat stability in Saccharomyces cerevisiae. DNA Repair (Amst) 2006; 6:38-44. [PMID: 16979389 DOI: 10.1016/j.dnarep.2006.08.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2006] [Revised: 07/31/2006] [Accepted: 08/14/2006] [Indexed: 11/30/2022]
Abstract
Trinucleotide repeats (TNRs) frequently expand in certain human genetic diseases, often with devastating pathological consequences. TNR expansions require the addition of new DNA; accordingly, molecular models suggest aberrant DNA replication or error-prone repair synthesis as the sources of most instability. Some proteins are currently known that either promote or inhibit TNR mutability. To identify additional proteins that help protect cells against TNR instability, yeast mutants were isolated with higher than normal rates of CAG.CTG tract expansions. Surprisingly, a rev1 mutant was isolated. In contrast to its canonical function in supporting mutagenesis, we found that Rev1 reduces rates of CAG.CTG repeat expansions and contractions, as judged by the behavior of the rev1 mutant. The rev1 mutator phenotype was specific for TNRs with hairpin forming capacity. Mutations in REV3 or REV7, encoding the subunits of DNA polymerase zeta (pol zeta), did not affect expansion rates in REV1 or rev1 strains. A rev1 point mutant lacking dCMP transferase activity was normal for TNR instability, whereas the rev1-1 allele that interferes with BRCT domain function was as defective as a rev1 null mutant. In summary, these results indicate that yeast Rev1 reduces mutability of CAG.CTG tracts in a manner dependent on BRCT domain function but independent of dCMP transferase activity and of pol zeta.
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Affiliation(s)
- Natasha S Collins
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Box 986805, Omaha, NE 68198-6805, United States
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54
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Yuasa MS, Masutani C, Hirano A, Cohn MA, Yamaizumi M, Nakatani Y, Hanaoka F. A human DNA polymerase eta complex containing Rad18, Rad6 and Rev1; proteomic analysis and targeting of the complex to the chromatin-bound fraction of cells undergoing replication fork arrest. Genes Cells 2006; 11:731-44. [PMID: 16824193 DOI: 10.1111/j.1365-2443.2006.00974.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
DNA polymerase eta (Poleta) is responsible for efficient translesion synthesis (TLS) past cis-syn cyclobutane thymine dimers (TT dimers), the major DNA lesions induced by UV irradiation. Loss of human Poleta leads to xeroderma pigmentosum variant syndrome, clearly indicating that Poleta plays a vital role in preventing skin cancer caused by exposure to sunlight. To further examine Poleta functions and the mechanisms that regulate this important protein, Poleta complexes were purified from HeLa cells over-expressing epitope-tagged Poleta, and polypeptides associated with Poleta, including Rad18, Rad6 and Rev1, were identified by a combination of mass spectrometry and Western blot analysis. The chromatin-bound fractions of cells subjected to UV irradiation, S phase synchronization, or S phase arrest were specifically enriched in such complexes. These results suggest that arrested replication forks strengthen interactions among Poleta, Rad18/Rad6 and Rev1, consistent with the requirement for effective TLS by Poleta at sites of DNA lesions.
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Affiliation(s)
- Mayumi S Yuasa
- Graduate School of Frontier Biosciences, Osaka University, and SORST, Japan Science and Technology Agency, 1-3 Yamada-Oka, Suita, Osaka 565-0871, Japan
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55
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Ohkumo T, Kondo Y, Yokoi M, Tsukamoto T, Yamada A, Sugimoto T, Kanao R, Higashi Y, Kondoh H, Tatematsu M, Masutani C, Hanaoka F. UV-B radiation induces epithelial tumors in mice lacking DNA polymerase eta and mesenchymal tumors in mice deficient for DNA polymerase iota. Mol Cell Biol 2006; 26:7696-706. [PMID: 17015482 PMCID: PMC1636855 DOI: 10.1128/mcb.01076-06] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
DNA polymerase eta (Pol eta) is the product of the Polh gene, which is responsible for the group variant of xeroderma pigmentosum, a rare inherited recessive disease which is characterized by susceptibility to sunlight-induced skin cancer. We recently reported in a study of Polh mutant mice that Pol eta is involved in the somatic hypermutation of immunoglobulin genes, but the cancer predisposition of Polh-/- mice has not been examined until very recently. Another translesion synthesis polymerase, Pol iota, a Pol eta paralog encoded by the Poli gene, is naturally deficient in the 129 mouse strain, and the function of Pol iota is enigmatic. Here, we generated Polh Poli double-deficient mice and compared the tumor susceptibility of them with Polh- or Poli-deficient animals under the same genetic background. While Pol iota deficiency does not influence the UV sensitivity of mouse fibroblasts irrespective of Polh genotype, Polh Poli double-deficient mice show slightly earlier onset of skin tumor formation. Intriguingly, histological diagnosis after chronic treatment with UV light reveals that Pol iota deficiency leads to the formation of mesenchymal tumors, such as sarcomas, that are not observed in Polh(-/-) mice. These results suggest the involvement of the Pol eta and Pol iota proteins in UV-induced skin carcinogenesis.
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Affiliation(s)
- Tsuyoshi Ohkumo
- Cellular Biology Laboratory, Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamada-oka, Suita, Osaka 565-0871, Japan
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56
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Abstract
Cellular functions of the REV1 gene have been conserved in evolution and appear important for maintaining genetic integrity through translesion DNA synthesis. This study documents a novel biochemical activity of human REV1 protein, due to higher affinity for single-stranded DNA (ssDNA) than the primer terminus. Preferential binding to long ssDNA regions of the template strand means that REV1 is targeted specifically to the included primer termini, a property not shared by other DNA polymerases, including human DNA polymerases alpha, beta, and eta. Furthermore, a mutant REV1 lacking N- and C-terminal domains, but catalytically active, lost this function, indicating that control is not due to the catalytic core. The novel activity of REV1 protein might imply a role for ssDNA in the regulation of translesion DNA synthesis.
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Affiliation(s)
- Yuji Masuda
- Research Institute for Radiation Biology and Medicine, Hiroshima University, Hiroshima 734-8553, Japan
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57
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Lehmann AR. Translesion synthesis in mammalian cells. Exp Cell Res 2006; 312:2673-6. [PMID: 16854411 DOI: 10.1016/j.yexcr.2006.06.010] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2006] [Accepted: 06/14/2006] [Indexed: 11/27/2022]
Abstract
DNA damage blocks the progression of the replication fork. In order to circumvent the damaged bases, cells employ specialized low stringency DNA polymerases, which are able to carry out translesion synthesis (TLS) past different types of damage. The five polymerases used in TLS in human cells have different substrate specificities, enabling them to deal with many different types of damaged bases. PCNA plays a central role in recruiting the TLS polymerases and effecting the polymerase switch from replicative to TLS polymerase. When the fork is blocked PCNA gets ubiquitinated. This increases its affinity for the TLS polymerases, which all have novel ubiquitin-binding motifs, thereby facilitating their engagement at the stalled fork to effect TLS.
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Affiliation(s)
- Alan R Lehmann
- Genome Damage and Stability Centre, University of Sussex, Falmer, Brighton, UK.
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58
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Cheung HW, Chun ACS, Wang Q, Deng W, Hu L, Guan XY, Nicholls JM, Ling MT, Chuan Wong Y, Tsao SW, Jin DY, Wang X. Inactivation of human MAD2B in nasopharyngeal carcinoma cells leads to chemosensitization to DNA-damaging agents. Cancer Res 2006; 66:4357-67. [PMID: 16618761 DOI: 10.1158/0008-5472.can-05-3602] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Rev7p has been suggested to play an important role in regulating DNA damage response in yeast, and recently, the human homologue (i.e., MAD2B) has been identified, which shares significant homology to the mitotic checkpoint protein MAD2. In this study, we investigated whether MAD2B played a key role in cellular sensitivity to DNA-damaging anticancer drugs by suppressing its expression using RNA interference in nasopharyngeal carcinoma cells. Using colony formation assay, we found that suppression of MAD2B conferred hypersensitivity to a range of DNA-damaging agents, especially DNA cross-linkers, such as cisplatin, and gamma-irradiation. This effect was associated with reduced frequencies of spontaneous and drug-induced mutations, elevated phosphorylation of histone H2AX, and markedly increased chromosomal aberrations in response to DNA damage. In addition, there was also a significant decrease in cisplatin-induced sister chromatid exchange rate, a marker for homologous recombination-mediated post-replication repair in MAD2B-depleted cells. These results indicate that MAD2B may be a key factor in regulating cellular response to DNA damage in cancer cells. Our findings reveal a novel strategy for cancer therapy, in which cancer cells are sensitized to DNA-damaging anticancer drugs through inactivation of the MAD2B gene.
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Affiliation(s)
- Hiu Wing Cheung
- Department of Anatomy, Faculty of Medicine, The University of Hong Kong, Hong Kong, China
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59
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Waters LS, Walker GC. The critical mutagenic translesion DNA polymerase Rev1 is highly expressed during G(2)/M phase rather than S phase. Proc Natl Acad Sci U S A 2006; 103:8971-6. [PMID: 16751278 PMCID: PMC1482550 DOI: 10.1073/pnas.0510167103] [Citation(s) in RCA: 142] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
The Rev1 protein lies at the root of mutagenesis in eukaryotes. Together with DNA polymerase zeta (Rev3/7), Rev1 function is required for the active introduction of the majority of mutations into the genomes of eukaryotes from yeast to humans. Rev1 and polymerase zeta are error-prone translesion DNA polymerases, but Rev1's DNA polymerase catalytic activity is not essential for mutagenesis. Rather, Rev1 is thought to contribute to mutagenesis principally by engaging in crucial protein-protein interactions that regulate the access of translesion DNA polymerases to the primer terminus. This inference is based on the requirement of the N-terminal BRCT (BRCA1 C-terminal) domain of Saccharomyces cerevisiae Rev1 for mutagenesis and the interaction of the C-terminal region of mammalian Rev1 with several other translesion DNA polymerases. Here, we report that S. cerevisiae Rev1 is subject to pronounced cell cycle control in which the levels of Rev1 protein are approximately 50-fold higher in G(2) and throughout mitosis than during G(1) and much of S phase. Differential survival of a rev1Delta strain after UV irradiation at various points in the cell cycle indicates that this unanticipated regulation is physiologically relevant. This unexpected finding has important implications for the regulation of mutagenesis and challenges current models of error-prone lesion bypass as a process involving polymerase switching that operates mainly during S phase to rescue stalled replication forks.
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Affiliation(s)
- Lauren S. Waters
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - Graham C. Walker
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139
- *To whom correspondence should be addressed at:
Department of Biology, Massachusetts Institute of Technology, Building 68-633, Cambridge, MA 02139. E-mail:
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60
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Murakumo Y, Mizutani S, Yamaguchi M, Ichihara M, Takahashi M. Analyses of ultraviolet-induced focus formation of hREV1 protein. Genes Cells 2006; 11:193-205. [PMID: 16483309 DOI: 10.1111/j.1365-2443.2006.00938.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Translesional DNA synthesis (TLS) is one of the DNA damage tolerance mechanisms that allow cells with DNA damage to continue DNA replication. Each of the mammalian Y-family DNA polymerases (Pol eta, Pol iota, Pol kappa, and REV1) has been shown to carry out TLS by itself or in combination with another enzyme in vitro. Recently, the C-terminal region of mammalian REV1 (the total 1251 residues in human) was found to interact with Pol eta, Pol iota, and Pol kappa, as well as with the REV7 subunit of another TLS enzyme, Pol zeta. Thus, it is proposed that REV1 plays a pivotal role in TLS in vivo. We here describe our study on the localization of human REV1 protein (hREV1) in nondamaged and ultraviolet (UV)-irradiated cells. Ectopically expressed hREV1 in mammalian cells was localized to the nucleus and exhibited dozens of tiny foci in approximately 3% of nondamaged cells. The percentage of focus-forming cells markedly increased after UV irradiation in a time- and dose-dependent manner. The focus formation was associated with UV-induced DNA damage. Interestingly, although the hREV1 foci in S-phase cells colocalized with PCNA foci, suggesting the association of hREV1 with the replication machinery, hREV1 focus formation was observed not only in the S phase but also outside S phase. Furthermore, it was found that the hREV1 focus formation after UV irradiation required a region near the C-terminal (826-1178).
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Affiliation(s)
- Yoshiki Murakumo
- Department of Pathology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan.
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61
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Lin X, Okuda T, Trang J, Howell SB. Human REV1 modulates the cytotoxicity and mutagenicity of cisplatin in human ovarian carcinoma cells. Mol Pharmacol 2006; 69:1748-54. [PMID: 16495473 DOI: 10.1124/mol.105.020446] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
REV1 interacts with Y-type DNA polymerases (Pol) and Pol zeta to bypass many types of adducts that block the replicative DNA polymerases. This pathway accounts for many of the mutations induced by cisplatin (cis-diamminedichloroplatinium II, DDP). This study sought to determine how increasing human REV1 (hREV1) affects the cytotoxicity and mutagenicity of DDP. Human ovarian carcinoma 2008 cells were transfected with an hREV1 expression vector and 4 sublines developed in which the hREV1 mRNA level was increased by 6.3- to 23.4-fold and hREV1 protein by 2.7- to 6.2-fold. The sublines were 1.3- to 1.7-fold resistant to the cytotoxic effect of DDP and 2.3- to 5.1-fold hypersensitive to the mutagenic effect of DDP. The hREV1-transfected sublines were 1.5- to 1.8-fold better than the parental 2008 cells at managing DDP adducts as assessed by their ability to express Renilla reniformis luciferase from a vector that had been extensively loaded with DDP adducts before transfection. Increased hREV1 expression was associated with a 1.5-fold increase in the rate at which the whole population acquired resistance to DDP during sequential cycles of drug exposure. Increasing the abundance of hREV1 thus resulted in both resistance to DDP and a significant elevation in DDP-induced mutagenicity. This was accompanied by an enhanced capacity to synthesize a functional protein from a DDP-damaged gene and, most importantly, by more rapid development of resistance during sequential cycles of DDP exposure that mimic clinical schedules of DDP administration. We conclude that hREV1-dependent processes are important determinants of DDP-induced genomic instability and the development of resistance.
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Affiliation(s)
- Xinjian Lin
- Department of Medicine and the Moores UCSD Cancer Center, University of California, San Diego, 3855 Health Sciences Drive, La Jolla, CA 92093-0819, USA
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62
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Seki M, Gearhart PJ, Wood RD. DNA polymerases and somatic hypermutation of immunoglobulin genes. EMBO Rep 2006; 6:1143-8. [PMID: 16319960 PMCID: PMC1369213 DOI: 10.1038/sj.embor.7400582] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2005] [Accepted: 10/17/2005] [Indexed: 11/08/2022] Open
Abstract
Somatic hypermutation of immunoglobulin variable genes, which increases antibody diversity, is initiated by the activation-induced cytosine deaminase (AID) protein. The current DNA-deamination model posits that AID deaminates cytosine to uracil in DNA, and that mutations are generated by DNA polymerases during replication or repair of the uracil residue. Mutations could arise as follows: by DNA replicating past the uracil; by removing the uracil with a uracil glycosylase and replicating past the resulting abasic site with a low-fidelity polymerase; or by repairing the uracil and synthesizing a DNA-repair patch downstream using a low-fidelity polymerase. In this review, we summarize the biochemical properties of specialized DNA polymerases in mammalian cells and discuss their participation in the mechanisms of hypermutation. Many recent studies have examined mice deficient in the genes that encode various DNA polymerases, and have shown that DNA polymerase H (POLH) contributes to hypermutation, whereas POLI, POLK and several other enzymes do not have major roles. The low-fidelity enzyme POLQ has been proposed as another candidate polymerase because it can efficiently bypass abasic sites and recent evidence indicates that it might participate in hypermutation.
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Affiliation(s)
- Mineaki Seki
- Suite 2.6, Research Pavilion, Hillman Cancer Center, University of Pittsburgh Cancer Institute, 5117 Centre Avenue, Pittsburgh, Pennsylvania 15213, USA
| | - Patricia J Gearhart
- Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health, 5600 Nathan Shock Drive, Baltimore, Maryland 21224, USA
| | - Richard D Wood
- Suite 2.6, Research Pavilion, Hillman Cancer Center, University of Pittsburgh Cancer Institute, 5117 Centre Avenue, Pittsburgh, Pennsylvania 15213, USA
- Tel: +1 412 623 7766; Fax: +1 412 623 7761; E-mail:
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63
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Adar S, Livneh Z. Translesion DNA synthesis across non-DNA segments in cultured human cells. DNA Repair (Amst) 2006; 5:479-90. [PMID: 16473566 DOI: 10.1016/j.dnarep.2006.01.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2005] [Revised: 01/05/2006] [Accepted: 01/09/2006] [Indexed: 11/17/2022]
Abstract
DNA lesions that have escaped DNA repair are tolerated via translesion DNA synthesis (TLS), carried out by specialized error-prone DNA polymerases. To evaluate the robustness of the TLS system in human cells, we examined its ability to cope with foreign non-DNA stretches of 3 or 12 methylene residues, using a gap-lesion plasmid assay system. We found that both the trimethylene and dodecamethylene inserts were bypassed with significant efficiencies in human cells, using both misinsertion and misalignment mechanisms. TLS across these non-DNA segments was aphidicolin-sensitive, and did not require poleta. In vitro primer extension assays showed that purified poleta, polkappa and poliota were each capable of inserting each of the four nucleotides opposite the trimethylene chain, but only poleta and polkappa could fully bypass it. Poleta and poliota, but not polkappa, could also insert each of the four nucleotides opposite the dodecamethylene chain, but all three polymerases were severely blocked by this lesion. The ability of TLS polymerases to insert nucleotides opposite a hydrocarbon chain, despite the lack of any similarity to DNA, suggests that they may act via a mode of transient and local template-independent polymerase activity, and highlights the robustness of the TLS system in human cells.
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Affiliation(s)
- Sheera Adar
- Department of Biological Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel
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64
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Choi JH, Besaratinia A, Lee DH, Lee CS, Pfeifer GP. The role of DNA polymerase iota in UV mutational spectra. Mutat Res 2006; 599:58-65. [PMID: 16472831 DOI: 10.1016/j.mrfmmm.2006.01.003] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2005] [Revised: 01/07/2006] [Accepted: 01/10/2006] [Indexed: 11/20/2022]
Abstract
UVB (280-320 nm) and UVC (200-280 nm) irradiation generate predominantly cyclobutane pyrimidine dimers (CPDs) and (6-4) photoproducts in DNA. CPDs are thought to be responsible for most of the UV-induced mutations. Thymine-thymine CPDs, and probably also CPDs containing cytosine, are replicated in vivo in a largely accurate manner by a DNA polymerase eta (Pol eta) dependent process. Pol eta is a DNA damage-tolerant and error-prone DNA polymerase encoded by the POLH (XPV) gene in humans. Another member of the Y family of error-prone DNA polymerases is POLI encoding DNA polymerase iota (Pol iota). In order to clarify the specific role of Pol iota in UV mutagenesis, we have used an siRNA knockdown approach in combination with a supF shuttle vector which replicates in mammalian cells, similar as we have previously done for Pol eta. Synthetic RNA duplexes were used to efficiently inhibit Pol iota expression in 293 T cells. The supF shuttle vector was irradiated with 254 nm UVC and replicated in 293 T cells in presence of anti-Pol iota siRNA. Surprisingly, there was a consistent reduction of recovered plasmid from cells with Pol iota knockdown and this was independent of UV irradiation of the plasmid. The supF mutant frequency was unchanged in the siRNA knockdown cells relative to control cells confirming that Pol iota does not play an important role in UV mutagenesis. UV-induced supF mutants were sequenced from siRNA-treated cells and controls. Neither the type of mutations nor their distribution along the supF gene were significantly different between controls and siRNA knockdown cells and were predominantly C to T and CC to TT transitions at dipyrimidine sites. These results show that Pol iota has no significant role in UV lesion bypass and mutagenesis in vivo and provides some initial data suggesting that this polymerase may be involved in replication of extrachromosomal DNA.
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Affiliation(s)
- Jun-Hyuk Choi
- Division of Biology, Beckman Research Institute, City of Hope, Duarte, CA 91010, USA
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65
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Abstract
The MtArg8 reversion assay, which measures point mutation in mtDNA, indicates that in budding yeast Saccharomyces cerevisiae, DNA polymerase zeta and Rev1 proteins participate in the mitochondrial DNA mutagenesis. Supporting this evidence, both polymerase zeta and Rev1p were found to be localized in the mitochondria. This is the first report demonstrating that the DNA polymerase zeta and Rev1 proteins function in the mitochondria.
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Affiliation(s)
- Hengshan Zhang
- Department of Cancer Genetics, Roswell Park Cancer Institute, Buffalo, New York 14263, USA
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66
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Poltoratsky V, Horton JK, Prasad R, Wilson SH. REV1 mediated mutagenesis in base excision repair deficient mouse fibroblast. DNA Repair (Amst) 2006; 4:1182-8. [PMID: 15950550 DOI: 10.1016/j.dnarep.2005.05.002] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2005] [Revised: 05/03/2005] [Accepted: 05/03/2005] [Indexed: 12/22/2022]
Abstract
The DNA polymerase beta (Pol beta) null background renders mouse embryonic fibroblast (MEF) cells base excision repair deficient and hyper-mutagenic upon treatment with the monofunctional alkylating agent, methyl methanesulfonate (MMS). This effect involves an increase in all types of base substitutions, with a modest predominance of G to A transitions. In the present study, we examined the hypothesis that the MMS-induced mutagenesis in the Pol beta null MEF system is due to a lesion bypass mechanism. We studied the effect of RNAi mediated down-regulation of the lesion bypass factor REV1. The steady-state level of REV1 protein was reduced by more than 95% using stable expression of a siRNA construct in a Pol beta null cell line. We found that REV1 expression is required for the MMS-induced mutagenesis phenotype of Pol beta null MEF cells. In contrast, cell survival after MMS treatment is not reduced in the absence of REV1.
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Affiliation(s)
- Vladimir Poltoratsky
- Laboratory of Structural Biology, NIEHS, National Institutes of Health, Research Triangle Park, NC 27709, USA
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67
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Ohkumo T, Masutani C, Eki T, Hanaoka F. Deficiency of the Caenorhabditis elegans DNA Polymerase .ETA. Homologue Increases Sensitivity to UV Radiation during Germ-line Development. Cell Struct Funct 2006; 31:29-37. [PMID: 16565574 DOI: 10.1247/csf.31.29] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Defects in the human XPV/POLH gene result in the variant form of the disease xeroderma pigmentosum (XP-V). The gene encodes DNA polymerase eta (Poleta), which catalyzes translesion synthesis (TLS) past UV-induced cyclobutane pyrimidine dimers (CPDs) and other lesions. To further understand the roles of Poleta in multicellular organisms, we analyzed phenotypes caused by suppression of Caenorhabditis elegans POLH (Ce-POLH) by RNA interference (RNAi). F1 and F2 progeny from worms treated by Ce-POLH-specific RNAi grew normally, but F1 eggs laid by worms treated by RNAi against Ce-POLD, which encodes Poldelta did not hatch. These results suggest that Poldelta but not Poleta is essential for C. elegans embryogenesis. Poleta-targeted embryos UV-irradiated after egg laying were only moderately sensitive. In contrast, Poleta-targeted embryos UV-irradiated prior to egg laying exhibited severe sensitivity, indicating that Poleta contributes significantly to damage tolerance in C. elegans in early embryogenesis but only modestly at later stages. As early embryogenesis is characterized by high levels of DNA replication, Poleta may confer UV resistance in C. elegans, perhaps by catalyzing TLS in early embryogenesis.
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Affiliation(s)
- Tsuyoshi Ohkumo
- Graduate School of Frontier Biosciences, Osaka University, SORST, Japan Science and Technology Agency, Japan
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68
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Otsuka C, Kunitomi N, Iwai S, Loakes D, Negishi K. Roles of the polymerase and BRCT domains of Rev1 protein in translesion DNA synthesis in yeast in vivo. Mutat Res 2005; 578:79-87. [PMID: 15896814 DOI: 10.1016/j.mrfmmm.2005.03.005] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2004] [Revised: 03/11/2005] [Accepted: 03/29/2005] [Indexed: 10/25/2022]
Abstract
Rev1p in yeast is essential for the translesion of abasic sites and 6-4 photoproducts. It plays a role as a translesion polymerase, but also supports translesion catalyzed by other polymerases. The protein has two domains, BRCT and Y-family polymerase. A point mutation in the BRCT domain is known to abolish the second function. In the present research, we have studied the effects of deletion of the BRCT domain and a point mutation at the two amino acids in the putative polymerase active center. We have introduced an abasic site, its tetrahydrofuran analog, and a 6-4 thymine-thymine photoproduct using the oligonucleotide transformation assay. Translesion efficiencies were estimated from the transforming activities of the oligonucleotides with a lesion, and the mutation spectra were analyzed by DNA sequencing of the transformants. Results showed that the lack of the BRCT domain reduced translesion efficiencies, but that substantial translesion synthesis took place. The mutation spectra of the lesions were not greatly affected. Therefore, the BRCT domain may be important, but dispensable for translesion synthesis. In contrast, the polymerase mutation, rev1AA, has only small effects on the translesion efficiencies, but the mutation spectra were greatly affected; the incorporation of dCMP opposite the lesions was specifically lost. This clearly shows that the polymerase domain is responsible for the dCMP incorporation. The effect of Poleta was also analyzed. From all the results DNA polymerases other than these two translesion polymerases, too, seem to initiate the translesion synthesis.
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Affiliation(s)
- Chie Otsuka
- Department of Genomics and Proteomics, Okayama University Advanced Science Research Center, Tsushima, Okayama 700-8530, Japan
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69
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Watson NB, Mukhopadhyay S, McGregor WG. Translesion DNA replication proteins as molecular targets for cancer prevention. Cancer Lett 2005; 241:13-22. [PMID: 16303242 DOI: 10.1016/j.canlet.2005.10.013] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2005] [Revised: 10/10/2005] [Accepted: 10/13/2005] [Indexed: 01/10/2023]
Abstract
Mutations in DNA are generally considered to have an etiologic role in the development of cancer. If so, it follows that reducing the frequency of such mutations will reduce the incidence of cancer induced by mutagens. Recent advances in elucidating the molecular mechanisms of carcinogen-induced mutagenesis indicate that replication of DNA templates that contain replication-blocking adducts is accomplished with error-prone DNA polymerases. These polymerases have relaxed base-pairing requirements, and can insert bases across from adducted templates, but with potentially mutagenic consequences. In principle, these proteins present new and attractive molecular targets to reduce mutagenesis. If this can be done in vivo without increasing cytotoxic responses to carcinogens, then novel chemopreventive strategies can be designed to reduce the risk of cancer in exposed populations prior to the appearance of disease symptoms.
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Affiliation(s)
- Nicholas B Watson
- Department of Pharmacology and Toxicology, University of Louisville, Louisville, KY 40202, USA
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70
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Ross AL, Sale JE. The catalytic activity of REV1 is employed during immunoglobulin gene diversification in DT40. Mol Immunol 2005; 43:1587-94. [PMID: 16263170 DOI: 10.1016/j.molimm.2005.09.017] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2005] [Accepted: 09/24/2005] [Indexed: 11/29/2022]
Abstract
REV1 plays a key role in vertebrate translesion synthesis. Although its deoxycytidyl transferase activity is dispensable for tolerance of DNA damage caused by a number of mutagens, its extreme C terminus, which interacts with other translesion polymerases and PCNA, is essential. By examining immunoglobulin diversification in the genetically tractable chicken cell line DT40 we show that the generation of non-templated point mutations from C/G to G/C does require the catalytic activity of REV1. This provides the first clear evidence that the catalytic activity of REV1 is utilised in vivo in higher eukaryotes and is involved in immunoglobulin diversification. Although rev1 DT40 cells incorporate few point mutations, a mutant lacking the C terminus of REV1 exhibits a similar level to that seen in wild-type cells. Thus, the polymerase selection or stabilisation role of REV1 does not appear to play a major role in the bypass of AID-dependent abasic sites.
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Affiliation(s)
- Anna-Laura Ross
- Medical Research Council Laboratory of Molecular Biology, Division of Protein and Nucleic Acid Chemistry, Hills Road, Cambridge, CB2 2QH, UK
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71
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Garinis GA, Mitchell JR, Moorhouse MJ, Hanada K, de Waard H, Vandeputte D, Jans J, Brand K, Smid M, van der Spek PJ, Hoeijmakers JHJ, Kanaar R, van der Horst GTJ. Transcriptome analysis reveals cyclobutane pyrimidine dimers as a major source of UV-induced DNA breaks. EMBO J 2005; 24:3952-62. [PMID: 16252008 PMCID: PMC1283948 DOI: 10.1038/sj.emboj.7600849] [Citation(s) in RCA: 118] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2005] [Accepted: 09/30/2005] [Indexed: 12/11/2022] Open
Abstract
Photolyase transgenic mice have opened new avenues to improve our understanding of the cytotoxic effects of ultraviolet (UV) light on skin by providing a means to selectively remove either cyclobutane pyrimidine dimers (CPDs) or pyrimidine (6-4) pyrimidone photoproducts. Here, we have taken a genomics approach to delineate pathways through which CPDs might contribute to the harmful effects of UV exposure. We show that CPDs, rather than other DNA lesions or damaged macromolecules, comprise the principal mediator of the cellular transcriptional response to UV. The most prominent pathway induced by CPDs is that associated with DNA double-strand break (DSB) signalling and repair. Moreover, we show that CPDs provoke accumulation of gamma-H2AX, P53bp1 and Rad51 foci as well as an increase in the amount of DSBs, which coincides with accumulation of cells in S phase. Thus, conversion of unrepaired CPD lesions into DNA breaks during DNA replication may comprise one of the principal instigators of UV-mediated cytotoxicity.
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Affiliation(s)
- George A Garinis
- Department of Cell Biology and Genetics, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - James R Mitchell
- Department of Cell Biology and Genetics, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Michael J Moorhouse
- Department of Bioinformatics, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Katsuhiro Hanada
- Department of Cell Biology and Genetics, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Harm de Waard
- Department of Cell Biology and Genetics, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Dimitri Vandeputte
- Department of Cell Biology and Genetics, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Judith Jans
- Department of Cell Biology and Genetics, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Karl Brand
- Department of Cell Biology and Genetics, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Marcel Smid
- Department of Medical Oncology, Josephine Nefkens Institute, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Peter J van der Spek
- Department of Bioinformatics, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Jan H J Hoeijmakers
- Department of Cell Biology and Genetics, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Roland Kanaar
- Department of Cell Biology and Genetics, Erasmus University Medical Center, Rotterdam, The Netherlands
- Department of Radiation Oncology, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Gijsbertus T J van der Horst
- Department of Cell Biology and Genetics, Erasmus University Medical Center, Rotterdam, The Netherlands
- Department of Cell Biology and Genetics, Center for Biomedical Genetics, Erasmus University Medical Center, PO Box 1738, 3000 DR Rotterdam, The Netherlands. Tel.: +31 10 408 7455; Fax: +31 10 408 9468; E-mail:
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72
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Takahashi S, Sakamoto A, Sato S, Kato T, Tabata S, Tanaka A. Roles of Arabidopsis AtREV1 and AtREV7 in translesion synthesis. PLANT PHYSIOLOGY 2005; 138:870-81. [PMID: 15908599 PMCID: PMC1150404 DOI: 10.1104/pp.105.060236] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Plants have mechanisms for repairing and tolerating detrimental effects by various DNA damaging agents. A tolerance pathway that has been predicted to be present in higher plants is translesion synthesis (TLS), which is catalyzed by polymerases. In Arabidopsis (Arabidopsis thaliana), however, the only gene known to be involved in TLS is the Arabidopsis homolog of REV3, AtREV3, which is a putative catalytic subunit of Arabidopsis DNA polymerase zeta. A disrupted mutant of AtREV3, rev3, was previously found to be highly sensitive to ultraviolet-B (UV-B) and various DNA damaging agents. REV1 and REV7 are thought to be components of translesion synthesis in plants. In this study, we identified the Arabidopsis homologs of REV1 and REV7 (AtREV1 and AtREV7). Several mutants carrying disrupted AtREV1 and AtREV7 genes were isolated from Arabidopsis T-DNA-inserted lines. An AtREV1-disrupted mutant, rev1, was found to be moderately sensitive to UV-B and DNA cross-linkers. A rev1rev3 double mutant, like rev3, showed high sensitivity to UV-B, gamma-rays, and DNA cross-linkers. An AtREV7-disrupted mutant, rev7, was possibly sensitive to cis-diamminedichloroplatinum(II), a kind of DNA cross-linker, but it was not sensitive to acute UV-B and gamma-ray irradiation. On the other hand, the aerial growth of rev7, like the aerial growth of rev1 and rev3, was inhibited by long-term UV-B. These results suggest that a TLS mechanism exists in a higher plant and show that AtREV1 and AtREV7 have important roles in tolerating exposure to DNA-damaging agents.
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Affiliation(s)
- Shinya Takahashi
- Department of Ion-beam-applied Biology, Japan Atomic Energy Research Institute, Watanuki 1233, Takasaki, Gunma, 370-1292, Japan.
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73
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Choi JH, Pfeifer GP. The role of DNA polymerase eta in UV mutational spectra. DNA Repair (Amst) 2005; 4:211-20. [PMID: 15590329 DOI: 10.1016/j.dnarep.2004.09.006] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2004] [Accepted: 09/20/2004] [Indexed: 11/29/2022]
Abstract
UV irradiation generates predominantly cyclobutane pyrimidine dimers (CPDs) and (6-4) photoproducts in DNA. CPDs are thought to be responsible for most of the UV-induced mutations. Thymine-thymine CPDs, and probably also CPDs containing cytosine, are replicated in vivo in a largely accurate manner by a DNA polymerase eta (Pol eta) dependent process. Pol eta is encoded by the POLH (XPV) gene in humans. In order to clarify the specific role of Pol eta in UV mutagenesis, we have used an siRNA knockdown approach in combination with a supF shuttle vector which replicates in mammalian cells. This strategy provides an advantage over studying mutagenesis in cell lines derived from normal individuals and XP-V patients, since the genetic background of the cells is identical. Synthetic RNA duplexes were used to inhibit Pol eta expression in 293T cells. The reduction of Pol eta mRNA and protein was greater than 90%. The supF shuttle vector was irradiated with UVC and replicated in 293T cells in presence of anti-Pol eta siRNA. The supF mutant frequency was increased by up to 3.6-fold in the siRNA knockdown cells relative to control cells confirming that Pol eta plays an important role in mutation avoidance and that the pol eta knockdown was efficient. UV-induced supF mutants were sequenced from siRNA-treated cells and controls. Surprisingly, neither the type of mutations nor their distribution along the supF gene were substantially different between controls and siRNA knockdown cells and were predominantly C to T and CC to TT transitions at dipyrimidine sites. The data are compatible with two models. (i) Incorrect replication of cytosine-containing photoproducts by a polymerase other than Pol eta produces similar mutations as when Pol eta is present but at a higher frequency. (ii) Due to lack of Pol eta or low levels of remaining Pol eta, lesion replication is delayed allowing more time for cytosine deamination within CPDs to occur. We provide proof of principle that siRNA technology can be used to dissect the in vivo roles of lesion bypass DNA polymerases in DNA damage-induced mutagenesis.
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Affiliation(s)
- Jun-Hyuk Choi
- Division of Biology, Beckman Research Institute, City of Hope, Duarte, CA 91010, USA
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74
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Tebbs RS, Hinz JM, Yamada NA, Wilson JB, Salazar EP, Thomas CB, Jones IM, Jones NJ, Thompson LH. New insights into the Fanconi anemia pathway from an isogenic FancG hamster CHO mutant. DNA Repair (Amst) 2005; 4:11-22. [PMID: 15533833 DOI: 10.1016/j.dnarep.2004.06.013] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2004] [Revised: 06/21/2004] [Accepted: 06/21/2004] [Indexed: 01/09/2023]
Abstract
The Fanconi anemia (FA) proteins overlap with those of homologous recombination through FANCD1/BRCA2, but the biochemical functions of other FA proteins are largely unknown. By constructing and characterizing a null fancg mutant (KO40) of hamster CHO cells, we show that FancG protects cells against a broad spectrum of genotoxic agents. KO40 is consistently hypersensitive to both alkylating agents that produce monoadducts and those that produce interstrand crosslinks. KO40 cells were no more sensitive to mitomycin C (3x) and diepoxybutane (2x) than to 6-thioguanine (5x), ethylnitrosourea (3x), or methyl methanesulfonate (MMS) (3x). These results contrast with the pattern of selective sensitivity to DNA crosslinking agents seen historically with cell lines from FA patients. The hypersensitivity of KO40 to MMS was not associated with a higher level of initial DNA single-strand breaks; nor was there a defect in removing MNU-induced methyl groups from DNA. Both control and MMS-treated synchronized G1-phase KO40 cells progressed through S phase at a normal rate but showed a lengthening of G2 phase compared with wild type. MMS-treated and untreated early S-phase KO40 cells had increased levels of Rad51 foci compared with wild type. Asynchronous KO40 treated with ionizing radiation (IR) exhibited a normal Rad51 focus response, consistent with KO40 having only slight sensitivity to killing by IR. The plating efficiency and doubling time of KO40 cells were nearly normal, and they showed no increase in spontaneous chromosomal aberrations or sister chromatid exchanges. Collectively, our results do not support a role for FancG during DNA replication that deals specifically with processing DNA crosslinks. Nor do they suggest that the main function of the FA protein "pathway" is to promote efficient homologous recombination. We propose that the primary function of FA proteins is to maintain chromosomal continuity by stabilizing replication forks that encounter nicks, gaps, or replication-blocking lesions.
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Affiliation(s)
- Robert S Tebbs
- Biology and Biotechnology Research Program, Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, CA 94551-0808, USA
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75
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Tissier A, Kannouche P, Reck MP, Lehmann AR, Fuchs RPP, Cordonnier A. Co-localization in replication foci and interaction of human Y-family members, DNA polymerase pol eta and REVl protein. DNA Repair (Amst) 2005; 3:1503-14. [PMID: 15380106 DOI: 10.1016/j.dnarep.2004.06.015] [Citation(s) in RCA: 172] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2004] [Revised: 06/13/2004] [Accepted: 06/15/2004] [Indexed: 11/17/2022]
Abstract
The progress of replicative DNA polymerases along the replication fork may be impeded by the presence of lesions in the genome. One way to circumvent such hurdles involves the recruitment of specialized DNA polymerases that perform limited incorporation of nucleotides in the vicinity of the damaged site. This process entails DNA polymerase switch between replicative and specialized DNA polymerases. Five eukaryotic proteins can carry out translesion synthesis (TLS) of damaged DNA in vitro, DNA polymerases zeta, eta, iota, and kappa, and REV1. To identify novel proteins that interact with hpol eta, we performed a yeast two-hybrid screen. In this paper, we show that hREV1 interacts with hpol eta as well as with hpol kappa and poorly with hpol iota. Furthermore, cellular localization analysis demonstrates that hREV1 is present, with hpol eta in replication factories at stalled replication forks and is tightly associated with nuclear structures. This hREV1 nuclear localization occurs independently of the presence of hpol eta. Taken together, our data suggest a central role for hREV1 as a scaffold that recruits DNA polymerases involved in TLS.
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Affiliation(s)
- Agnès Tissier
- UPR9OO3 - CNRS, Cancérogenèse et Mutagenèse Moléculaire et Structurale, ESBS, Pole API/Bd Sébastien Brant BP 10413, F-67412 - ILLKIRCH, France.
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76
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Lehmann AR. Replication of damaged DNA by translesion synthesis in human cells. FEBS Lett 2005; 579:873-6. [PMID: 15680966 DOI: 10.1016/j.febslet.2004.11.029] [Citation(s) in RCA: 104] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2004] [Accepted: 11/02/2004] [Indexed: 01/26/2023]
Abstract
Most types of DNA damage block the passage of the replication machinery. In order to bypass these blocks, cells employ special translesion synthesis (TLS) DNA polymerases, which have lower stringency than replicative polymerases. DNA polymerase eta is the major polymerase responsible for bypassing UV lesions in DNA and its absence results in the variant form of the genetic disorder, xeroderma pigmentosum. Other TLS polymerases have specificities for different types of damage, but their precise roles inside the cell have not yet been established. These polymerases are located in replication factories during DNA replication and the polymerase sliding clamp PCNA plays an important role in mediating switching between different polymerases.
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Affiliation(s)
- Alan R Lehmann
- Genome Damage and Stability Centre, University of Sussex, Falmer, Brighton BN1 9RQ, UK.
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77
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Okuda T, Lin X, Trang J, Howell SB. Suppression of hREV1 expression reduces the rate at which human ovarian carcinoma cells acquire resistance to cisplatin. Mol Pharmacol 2005; 67:1852-60. [PMID: 15758147 DOI: 10.1124/mol.104.010579] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Replicative bypass of many DNA adducts is dependent on the interaction of hREV1 with DNA polymerase zeta and potentially with members of the Y family of DNA polymerases. To examine the role of hREV1 in the development of cisplatin (DDP) resistance, a subline (2008-shREV1-3.3) of the ovarian carcinoma cell line 2008 was isolated in which stable expression of a short hairpin RNA suppressed hREV1 expression to 20% and reduced hREV1 protein level to 43% of that found in the parental cells. The 2008-shREV1-3.3 cells were 1.5-fold more sensitive to the cytotoxic effect of DDP but less sensitive to the mutagenic effect of DDP as evidenced by a 2.6- or 2.7-fold reduction in the ability to induce clones highly resistant to 6-thioguanine or DDP itself, respectively, in the surviving population. Reduction of hREV1 did not alter the initial rate of DDP adduct removal from DNA but did impair both spontaneous and DDP-induced extra-chromosomal homologous recombination, as measured by the recombination-sensitive reporter vector pBHRF. DDP induced an increase in hREV1 protein level. DDP resistance at the population level evolved 2.8-fold more slowly in the 2008-shREV1-3.3 cells than in the parental cells during repeated cycles of drug exposure. The results indicate that hREV1 functions to enhance both cell survival and the generation of drug-resistant variants in the surviving population. DDP up-regulates hREV1, suggesting that it may enhance its own mutagenicity. Most importantly, hREV1 controls the rate of emergence of resistance to DDP at the population level. Thus, hREV1 is an important contributor to DDP-induced genomic instability and the subsequent emergence of resistance.
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Affiliation(s)
- Tsuyoshi Okuda
- Department of Medicine 0058, University of California-San Diego, La Jolla, CA
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78
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Ross AL, Simpson LJ, Sale JE. Vertebrate DNA damage tolerance requires the C-terminus but not BRCT or transferase domains of REV1. Nucleic Acids Res 2005; 33:1280-9. [PMID: 15741181 PMCID: PMC552965 DOI: 10.1093/nar/gki279] [Citation(s) in RCA: 125] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2004] [Revised: 02/14/2005] [Accepted: 02/14/2005] [Indexed: 11/20/2022] Open
Abstract
REV1 is central to the DNA damage response of eukaryotes through an as yet poorly understood role in translesion synthesis. REV1 is a member of the Y-type DNA polymerase family and is capable of in vitro deoxycytidyl transferase activity opposite a range of damaged bases. However, non-catalytic roles for REV1 have been suggested by the Saccharomyces cerevisiae rev1-1 mutant, which carries a point mutation in the N-terminal BRCT domain, and the recently demonstrated ability of the mammalian protein to interact with each of the other translesion polymerases via its extreme C-terminus. Here, we show that a region adjacent to this polymerase interacting domain mediates an interaction with PCNA. These C-terminal domains of REV1 are necessary, although not sufficient, for effective tolerance of DNA damage in the avian cell line DT40, while the BRCT domain and transferase activity are not directly required. Together these data provide strong support for REV1 playing an important non-catalytic role in coordinating translesion synthesis. Further, unlike in budding yeast, rad18 is not epistatic to rev1 for DNA damage tolerance suggesting that REV1 and RAD18 play largely independent roles in the control of vertebrate translesion synthesis.
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Affiliation(s)
- Anna-Laura Ross
- Medical Research Council Laboratory of Molecular BiologyHills Road, Cambridge, CB2 2QH, UK
| | - Laura J. Simpson
- Medical Research Council Laboratory of Molecular BiologyHills Road, Cambridge, CB2 2QH, UK
| | - Julian E. Sale
- Medical Research Council Laboratory of Molecular BiologyHills Road, Cambridge, CB2 2QH, UK
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79
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Thompson LH, Hinz JM, Yamada NA, Jones NJ. How Fanconi anemia proteins promote the four Rs: replication, recombination, repair, and recovery. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2005; 45:128-142. [PMID: 15668941 DOI: 10.1002/em.20109] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The genetically complex disease Fanconi anemia (FA) comprises cancer predisposition, developmental defects, and bone marrow failure due to elevated apoptosis. The FA cellular phenotype includes universal sensitivity to DNA crosslinking damage, symptoms of oxidative stress, and reduced mutability at the X-linked HPRT gene. In this review article, we present a new heuristic molecular model that accommodates these varied features of FA cells. In our view, the FANCA, -C, and -G proteins, which are both cytoplasmic and nuclear, have an integrated dual role in which they sense and convey information about cytoplasmic oxidative stress to the nucleus, where they participate in the further assembly and functionality of the nuclear core complex (NCCFA= FANCA/B/C/E/F/G/L). In turn, NCCFA facilitates DNA replication at sites of base damage and strand breaks by performing the critical monoubiquitination of FANCD2, an event that somehow helps stabilize blocked and broken replication forks. This stabilization facilitates two kinds of processes: translesion synthesis at sites of blocking lesions (e.g., oxidative base damage), which produces point mutations by error-prone polymerases, and homologous recombination-mediated restart of broken forks, which arise spontaneously and when crosslinks are unhooked by the ERCC1-XPF endonuclease. In the absence of the critical FANCD2 monoubiquitination step, broken replication forks further lose chromatid continuity by collapsing into a configuration that is more difficult to restart through recombination and prone to aberrant repair through nonhomologous end joining. Thus, the FA regulatory pathway promotes chromosome integrity by monitoring oxidative stress and coping efficiently with the accompanying oxidative DNA damage during DNA replication.
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Affiliation(s)
- Larry H Thompson
- Biology and Biotechnology Research Program, Lawrence Livermore National Laboratory, Livermore, California 94551, USA.
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80
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Ohashi E, Murakumo Y, Kanjo N, Akagi JI, Masutani C, Hanaoka F, Ohmori H. Interaction of hREV1 with three human Y-family DNA polymerases. Genes Cells 2005; 9:523-31. [PMID: 15189446 DOI: 10.1111/j.1356-9597.2004.00747.x] [Citation(s) in RCA: 214] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Polkappa is one of many DNA polymerases involved in translesion DNA synthesis (TLS). It belongs to the Y-family of polymerases along with Poleta, Poliota and hREV1. Unlike Poleta encoded by the xeroderma pigmentosum variant (XPV) gene, Polkappa is unable to bypass UV-induced DNA damage in vitro, but it is able to bypass benzo[a]pyrene (B[a]P)-adducted guanines accurately and efficiently. In an attempt to identify factor(s) targeting Polkappa to its cognate DNA lesion(s), we searched for Polkappa-interacting proteins by using the yeast two-hybrid assay. We found that Polkappa interacts with a C-terminal region of hREV1. Poleta and Poliota were also found to interact with the same region of hREV1. The interaction between Polkappa and hREV1 was confirmed by pull-down and co-immunoprecipitation assays. The C-terminal region of hREV1 is known to interact with hREV7, a non-catalytic subunit of Polzeta that is another structurally unrelated TLS enzyme, and we show that Polkappa and hREV7 bind to the same C-terminal region of hREV1. Thus, our results suggest that hREV1 plays a pivotal role in the multi-enzyme, multi-step process of translesion DNA synthesis.
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Affiliation(s)
- Eiji Ohashi
- Institute for Virus Research, Kyoto University, 53 Shogoin-Kawaracho, Sakyo-ku, Kyoto 606-8507, Japan
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81
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Jansen JG, Tsaalbi-Shtylik A, Langerak P, Calléja F, Meijers CM, Jacobs H, de Wind N. The BRCT domain of mammalian Rev1 is involved in regulating DNA translesion synthesis. Nucleic Acids Res 2005; 33:356-65. [PMID: 15653636 PMCID: PMC546167 DOI: 10.1093/nar/gki189] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Rev1 is a deoxycytidyl transferase associated with DNA translesion synthesis (TLS). In addition to its catalytic domain, Rev1 possesses a so-called BRCA1 C-terminal (BRCT) domain. Here, we describe cells and mice containing a targeted deletion of this domain. Rev1B/B mice are healthy, fertile and display normal somatic hypermutation. Rev1B/B cells display an elevated spontaneous frequency of intragenic deletions at Hprt. In addition, these cells were sensitized to exogenous DNA damages. Ultraviolet-C (UV-C) light induced a delayed progression through late S and G2 phases of the cell cycle and many chromatid aberrations, specifically in a subset of mutant cells, but not enhanced sister chromatid exchanges (SCE). UV-C-induced mutagenesis was reduced and mutations at thymidine–thymidine dimers were absent in Rev1B/B cells, the opposite phenotype of UV-C-exposed cells from XP-V patients, lacking TLS polymerase η. This suggests that the enhanced UV-induced mutagenesis in XP-V patients may depend on error-prone Rev1-dependent TLS. Together, these data indicate a regulatory role of the Rev1 BRCT domain in TLS of a limited spectrum of endogenous and exogenous nucleotide damages during a defined phase of the cell cycle.
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Affiliation(s)
- Jacob G Jansen
- Department of Toxicogenetics, Leiden University Medical Center 2300 RA Leiden, The Netherlands
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82
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Avkin S, Goldsmith M, Velasco-Miguel S, Geacintov N, Friedberg EC, Livneh Z. Quantitative analysis of translesion DNA synthesis across a benzo[a]pyrene-guanine adduct in mammalian cells: the role of DNA polymerase kappa. J Biol Chem 2004; 279:53298-305. [PMID: 15475561 DOI: 10.1074/jbc.m409155200] [Citation(s) in RCA: 153] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Replication across unrepaired DNA lesions in mammalian cells is effected primarily by specialized, low fidelity DNA polymerases. We studied translesion DNA synthesis (TLS) across a benzo[a]pyrene-guanine (BP-G) adduct, a major mutagenic DNA lesion generated by tobacco smoke. This was done using a quantitative assay that measures TLS indirectly, by measuring the recovery of gapped plasmids transfected into cultured mammalian cells. Analysis of PolK(+/+) mouse embryo fibroblasts (MEFs) showed that TLS across the BP-G adduct occurred with an efficiency of 48 +/- 4%, which is an order of magnitude higher than in Escherichia coli. In PolK(-/-) MEFs, bypass was 16 +/- 1%, suggesting that at least two-thirds of the BP-G adducts in MEFs were bypassed exclusively by polymerase kappa (polkappa). In contrast, poleta was not required for bypass across BP-G in a human XP-V cell line. Analysis of misinsertion specificity across BP-G revealed that bypass was more error-prone in MEFs lacking polkappa. Expression of polkappa from a plasmid introduced into PolK(-/-) MEFs restored both the extent and fidelity of bypass across BP-G. Polkappa was not required for bypass of a synthetic abasic site. In vitro analysis demonstrated efficient bypass across BP-G by both polkappa and poleta, suggesting that the biological role of polkappa in TLS across BP-G is due to regulation of TLS and not due to an exclusive ability to bypass this lesion. These results indicate that BP-G is bypassed in mammalian cells with relatively high efficiency and that polkappa bypasses BP-G in vivo with higher efficiency and higher accuracy than other DNA polymerases.
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Affiliation(s)
- Sharon Avkin
- Department of Biological Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel
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83
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Mukhopadhyay S, Clark DR, Watson NB, Zacharias W, McGregor WG. REV1 accumulates in DNA damage-induced nuclear foci in human cells and is implicated in mutagenesis by benzo[a]pyrenediolepoxide. Nucleic Acids Res 2004; 32:5820-6. [PMID: 15523096 PMCID: PMC528789 DOI: 10.1093/nar/gkh903] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The REV1 gene encodes a Y-family DNA polymerase that has been postulated to have both catalytic and structural functions in translesion replication past UV photoproducts in mammalian cells. To examine if REV1 is implicated in DNA damage tolerance mechanisms after exposure of human cells to a chemical carcinogen, we generated a plasmid expressing REV1 protein fused at its C-terminus with green fluorescent protein (GFP). In transient transfection experiments, virtually all of the transfected cells had a diffuse nuclear pattern in the absence of carcinogen exposure. In contrast, in cells exposed to benzo[a]pyrenediolepoxide, the fusion protein accumulated in a focal pattern in the nucleus in 25% of the cells, and co-localized with PCNA. These data support the idea that REV1 is present at stalled replication forks. We also examined the mutagenic response at the HPRT locus of human cells that had greatly reduced levels of REV1 mRNA due to the stable expression of gene-specific ribozymes, and compared them to wild-type cells. The mutant frequency was greatly reduced in the ribozyme-expressing cells. These data indicate that REV1 is implicated in the mutagenic DNA damage tolerance response to BPDE and support the development of strategies to target this protein to prevent such mutations.
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Affiliation(s)
- Suparna Mukhopadhyay
- Department of Pharmacology and Toxicology, James Graham Brown Cancer Center, Louisville, KY, USA
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84
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Yang J, Chen Z, Liu Y, Hickey RJ, Malkas LH. Altered DNA polymerase iota expression in breast cancer cells leads to a reduction in DNA replication fidelity and a higher rate of mutagenesis. Cancer Res 2004; 64:5597-607. [PMID: 15313897 DOI: 10.1158/0008-5472.can-04-0603] [Citation(s) in RCA: 101] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The recently discovered human enzyme DNA polymerase iota (pol iota) has been shown to have an exceptionally high error rate on artificial DNA templates. Although there is a considerable body of in vitro evidence for a role for pol iota in DNA lesion bypass, there is no in vivo evidence to confirm this action. We report here that pol iota expression is elevated in breast cancer cells and correlates with a significant decrease in DNA replication fidelity. We also demonstrate that UV treatment of breast cancer cells additionally increases pol iota expression with a peak occurring between 30 min and 2 h after cellular insult. This implies that the change in pol iota expression is an early event after UV-mediated DNA damage. That pol iota may play a role in the higher mutation frequencies observed in breast cancer cells was suggested when a reduction in mutation frequency was found after pol iota was immunodepleted from nuclear extracts of the cells. Analysis of the UV-induced mutation spectra revealed that > 90% were point mutations. The analysis also demonstrated a decreased C --> T nucleotide transition and an increased C --> A transversion rate. Overall, our data strongly suggest that pol iota may be involved in the generation of both increased spontaneous and translesion mutations during DNA replication in breast cancer cells, thereby contributing to the accumulation of genetic damage.
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Affiliation(s)
- Jin Yang
- Department of Medicine, Division of Hematology/Oncology, Cancer Research Institute, Indiana University of School of Medicine, Indianapolis, Indiana 46202, USA
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85
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Abstract
Cells have high-fidelity polymerases whose task is to accurately replicate the genome, and low-fidelity polymerases with specialized functions. Although some of these low-fidelity polymerases are exceptional in their ability to replicate damaged DNA and restore the undamaged sequence, they are error prone on undamaged DNA. In fact, these error-prone polymerases are sometimes used in circumstances where the capacity to make errors has a selective advantage. The mutagenic potential of the error-prone polymerases requires that their expression, activity, and access to undamaged DNA templates be regulated. Here we review these specialized polymerases with an emphasis on their biological roles.
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Affiliation(s)
- Alison J Rattray
- Gene Regulation and Chromosome Biology Laboratory, NCI-Frederick, National Cancer Institute, National Institutes of Health, Frederick, Maryland 21702, USA.
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86
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Guo D, Xie Z, Shen H, Zhao B, Wang Z. Translesion synthesis of acetylaminofluorene-dG adducts by DNA polymerase zeta is stimulated by yeast Rev1 protein. Nucleic Acids Res 2004; 32:1122-30. [PMID: 14960722 PMCID: PMC373411 DOI: 10.1093/nar/gkh279] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Translesion synthesis is an important mechanism in response to unrepaired DNA lesions during replication. The DNA polymerase zeta (Polzeta) mutagenesis pathway is a major error-prone translesion synthesis mechanism requiring Polzeta and Rev1. In addition to its dCMP transferase, a non-catalytic function of Rev1 is suspected in cellular response to certain types of DNA lesions. However, it is not well understood about the non-catalytic function of Rev1 in translesion synthesis. We have analyzed the role of Rev1 in translesion synthesis of an acetylaminofluorene (AAF)-dG DNA adduct. Purified yeast Rev1 was essentially unresponsive to a template AAF-dG DNA adduct, in contrast to its efficient C insertion opposite a template 1,N6-ethenoadenine adduct. Purified yeast Polzeta was very inefficient in the bypass of the AAF-dG adduct. Combining Rev1 and Polzeta, however, led to a synergistic effect on translesion synthesis. Rev1 protein enhanced Polzeta-catalyzed nucleotide insertion opposite the AAF-dG adduct and strongly stimulated Polzeta-catalyzed extension from opposite the lesion. Rev1 also stimulated the deficient synthesis by Polzeta at the very end of undamaged DNA templates. Deleting the C-terminal 205 aa of Rev1 did not affect its dCMP transferase activity, but abolished its stimulatory activity on Polzeta-catalyzed extension from opposite the AAF-dG adduct. These results suggest that translesion synthesis of AAF-dG adducts by Polzeta is stimulated by Rev1 protein in yeast. Consistent with the in vitro results, both Polzeta and Rev1 were found to be equally important for error-prone translesion synthesis across from AAF-dG DNA adducts in yeast cells.
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Affiliation(s)
- Dongyu Guo
- Graduate Center for Toxicology, University of Kentucky, Lexington, KY 40536, USA
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87
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Brendel M, Bonatto D, Strauss M, Revers LF, Pungartnik C, Saffi J, Henriques JAP. Role of PSO genes in repair of DNA damage of Saccharomyces cerevisiae. Mutat Res 2004; 544:179-93. [PMID: 14644320 DOI: 10.1016/j.mrrev.2003.06.018] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Photoactivated psoralens used in treatment of skin diseases like Psoriasis and Vitiligo cause DNA damage, the repair of which may lead to mutations and thus to higher risk to have skin cancer. The simple eukaryote Saccharomyces cerevisiae was chosen to investigate the cells' genetic endowment with repair mechanisms for this type of DNA damage and to study the genetic consequences of such repair. Genetic studies on yeast mutants sensitive to photoactivated psoralens, named pso mutants, showed their allocation to 10 distinct loci. Cloning and molecular characterization allowed their grouping into three functional classes: (I) the largest group comprises seven PSO genes that are either generally or specifically involved in error-prone DNA repair and thus affect induced mutability and recombination; (II) one PSO gene that represents error-free excision repair, and (III) two PSO genes encoding proteins not influencing DNA repair but physiological processes unrelated to nucleic acid metabolism. Of the seven DNA repair genes involved in induced mutagenesis three PSO loci [PSO1/REV3, PSO8/RAD6, PSO9/MEC3] were allelic to already known repair genes, whereas three, PSO2/SNM1, PSO3/RNR4, and PSO4/PRP19 represent new genes involved in DNA repair and nucleic acid metabolism in S. cerevisiae. Gene PSO2 encodes a protein indispensable for repair of interstrand cross-link (ICL) that are produced in DNA by a variety of bi- and polyfunctional mutagens and that appears to be important for a likewise repair function in humans as well. In silico analysis predicts a putative endonucleolytic activity for Pso2p/Snm1p in removing hairpins generated as repair intermediates. The absence of induced mutation in pso3/rnr4 mutants indicates an important role of this subunit of ribonucleotide reductase (RNR) in regulation of translesion polymerase zeta in error-prone repair. Prp19p/Pso4p influences efficiency of DNA repair via splicing of pre-mRNAs of intron-containing repair genes but also may function in the stability of the nuclear scaffold that might influence DNA repair capacity. The seventh gene, PSO10 which controls an unknown step in induced mutagenesis is not yet cloned. Two genes, PSO6/ERG3 and PSO7/COX11, are responsible for structural elements of the membrane and for a functional respiratory chain (RC), respectively, and their function thus indirectly influences sensitivity to photoactivated psoralens.
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Affiliation(s)
- Martin Brendel
- Departamento de Biofisica, Centro de Biotecnologia, UFRGS, Av. Bento Gonçalves 9500, 91507-970 Porto Alegre, RS, Brazil
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88
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Lawrence CW. Cellular functions of DNA polymerase zeta and Rev1 protein. ADVANCES IN PROTEIN CHEMISTRY 2004; 69:167-203. [PMID: 15588843 DOI: 10.1016/s0065-3233(04)69006-1] [Citation(s) in RCA: 113] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Affiliation(s)
- Christopher W Lawrence
- Department of Biochemistry and Biophysics, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642, USA
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89
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Bunting KA, Roe SM, Pearl LH. Structural basis for recruitment of translesion DNA polymerase Pol IV/DinB to the beta-clamp. EMBO J 2003; 22:5883-92. [PMID: 14592985 PMCID: PMC275425 DOI: 10.1093/emboj/cdg568] [Citation(s) in RCA: 196] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2003] [Revised: 09/15/2003] [Accepted: 09/16/2003] [Indexed: 11/14/2022] Open
Abstract
Y-family DNA polymerases can extend primer strands across template strand lesions that stall replicative polymerases. The poor processivity and fidelity of these enzymes, key to their biological role, requires that their access to the primer-template junction is both facilitated and regulated in order to minimize mutations. These features are believed to be provided by interaction with processivity factors, beta-clamp or proliferating cell nuclear antigen (PCNA), which are also essential for the function of replicative DNA polymerases. The basis for this interaction is revealed by the crystal structure of the complex between the 'little finger' domain of the Y-family DNA polymerase Pol IV and the beta-clamp processivity factor, both from Escherichia coli. The main interaction involves a C-terminal peptide of Pol IV, and is similar to interactions seen between isolated peptides and other processivity factors. However, this first structure of an entire domain of a binding partner with an assembled clamp reveals a substantial secondary interface, which maintains the polymerase in an inactive orientation, and may regulate the switch between replicative and Y-family DNA polymerases in response to a template strand lesion.
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Affiliation(s)
- Karen A Bunting
- The Institute of Cancer Research, Chester Beatty Laboratories, 237 Fulham Road, London SW3 6JB, UK
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90
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Clark DR, Zacharias W, Panaitescu L, McGregor WG. Ribozyme-mediated REV1 inhibition reduces the frequency of UV-induced mutations in the human HPRT gene. Nucleic Acids Res 2003; 31:4981-8. [PMID: 12930947 PMCID: PMC212819 DOI: 10.1093/nar/gkg725] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
In yeast, mutations induced by UV radiation are dependent on the function of the Rev1 gene product, a Y-family DNA polymerase that assists in translesion replication with potentially mutagenic consequences. Human REV1 has been cloned, but its role in mutagenesis and carcinogenesis remains obscure. To examine the role of REV1 in UV mutagenesis in human cells and to evaluate its potential as a therapeutic target to prevent such mutations, we developed a ribozyme that cleaves human REV1 mRNA in vitro. Stable expression of the ribozyme in human cells reduced the target REV1 mRNA up to 90%. We examined the cytotoxic and mutagenic response to UV of seven independent clones that had reduced levels of endogenous REV1 mRNA. In each case, the clonogenic survival after UV was not different from that of the parental cell strains. In contrast, the UV-induced mutant frequencies at the endogenous HPRT locus were reduced up to 75% in cells with reduced levels of REV1 mRNA. The data support the idea that targeting the mutagenic translesion DNA replication pathway can greatly reduce the frequency of induced mutations.
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Affiliation(s)
- Denise R Clark
- Department of Pharmacology and Toxicology, University of Louisville School of Medicine, Louisville, KY 40202, USA
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91
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Yamada K, Takezawa J, Ezaki O. Translesion replication in cisplatin-treated xeroderma pigmentosum variant cells is also caffeine-sensitive: features of the error-prone DNA polymerase(s) involved in UV-mutagenesis. DNA Repair (Amst) 2003; 2:909-24. [PMID: 12893087 DOI: 10.1016/s1568-7864(03)00092-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Patients with xeroderma pigmentosum variant (XP-V) have a higher risk to skin cancer and XP-V cells are extremely mutable by ultraviolet (UV). The defective gene encodes a DNA polymerase (Poleta) which catalyzed relatively accurate translesion synthesis past the cyclobutane dimer of UV-lesions instead of the replicative polymerase(s) that stalled just before the lesion. Pulse-chase studies have shown that translesion replication in XP-V cells is delayed, but does not completely cease. Taking these results together, error-prone polymerase(s) are plausively involved in the UV-mutagenesis in XP-V devoid of Poleta. However, less is known about the polymerase(s) in vivo. Using an alkaline sucrose density gradient centrifugation (ASDG) technique, translesion replication is detected in the two XP-V strains XP30RO and XP115LO. As reported by Lehmann et al. [Proc. Natl. Acad. Sci. U.S.A. 72 (1975): 219] in XP-V; (i) smaller replication products were accumulated after UV irradiation; (ii) the elongation of these products was delayed; (iii) the elongation was markedly inhibited by caffeine. XP-V cells UV-irradiated at mid-S phase were normally S-arrested, and no "override" by caffeine (i.e. abrogation of the S-checkpoint) was observed by flow cytometry, suggesting that caffeine does not act via cdc kinase here; (iv) butylphenyldeoxyguanosine (BuPGdR) inhibited elongation of replication products only in UV-irradiated XP-V cells; (v) dideoxycytidine or dideoxyinosine had no effect on this process in either normal or XP-V cells. Next, similar phenomena to UV (all of above i to v) were observed also in cisplatin-treated XP-V cells. Pol eta was indicated to participate in cisplatin-induced translesion replication in normal cells. Summing up the above results, the polymerase(s) which work in translesion replication in XP-V are probably BuPGdR-sensitive, insensitive to dideoxynucleotides and can bypass also cisplatin-lesions. To date, several polymerases capable of lesion-bypass synthesis have been isolated. The features presented here are quite useful for identifying the error-prone polymerase(s) involved in UV-mutagenesis.
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Affiliation(s)
- Kouichi Yamada
- Division of Clinical Nutrition, The National Institute of Health and Nutrition, Shinjuku-ku, 162-8636 Tokyo, Japan.
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92
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Sonoda E, Okada T, Zhao GY, Tateishi S, Araki K, Yamaizumi M, Yagi T, Verkaik NS, van Gent DC, Takata M, Takeda S. Multiple roles of Rev3, the catalytic subunit of polzeta in maintaining genome stability in vertebrates. EMBO J 2003; 22:3188-97. [PMID: 12805232 PMCID: PMC162160 DOI: 10.1093/emboj/cdg308] [Citation(s) in RCA: 172] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Translesion DNA synthesis (TLS) and homologous DNA recombination (HR) are two major postreplicational repair (PRR) pathways. The REV3 gene of Saccharomyces cerevisiae encodes the catalytic subunit of DNA polymerase zeta, which is involved in mutagenic TLS. To investigate the role of REV3 in vertebrates, we disruped the gene in chicken DT40 cells. REV3(-/-) cells are sensitive to various DNA-damaging agents, including UV, methyl methanesulphonate (MMS), cisplatin and ionizing radiation (IR), consistent with its role in TLS. Interestingly, REV3(-/-) cells showed reduced gene targeting efficiencies and significant increase in the level of chromosomal breaks in the subsequent M phase after IR in the G(2) phase, suggesting the involvement of Rev3 in HR-mediated double-strand break repair. REV3(-/-) cells showed significant increase in sister chromatid exchange events and chromosomal breaks even in the absence of exogenous genotoxic stress. Furthermore, double mutants of REV3 and RAD54, genes involved in HR, are synthetic lethal. In conclusion, Rev3 plays critical roles in PRR, which accounts for survival on naturally occurring endogenous as well as induced damages during replication.
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Affiliation(s)
- Eiichiro Sonoda
- CREST Research Project, Japan Science and Technology, Radiation Genetics, Graduate School of Medicine, Kyoto University, Yoshida Konoe, Sakyo-ku, Kyoto 606-8501, Japan
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93
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Zhu F, Jin CX, Song T, Yang J, Guo L, Yu YN. Response of human REV3 gene to gastric cancer inducing carcinogen N-methyl- N’-nitro- N-nitrosoguanidine and its role in mutagenesis. World J Gastroenterol 2003; 9:888-93. [PMID: 12717825 PMCID: PMC4611392 DOI: 10.3748/wjg.v9.i5.888] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM: To understand the response of human REV3 gene to gastric cancer inducing carcinogen N-methyl-N’-nitro-N-nitrosoguanidine (MNNG) and its role in human mutagenesis.
METHODS: The response of the human REV3 gene to MNNG was measured in human 293 cells and FL cells by RT-PCR. By using antisense technology, mutation analysis at HPRT locus (on which lesion-targeted mutation usually occurs) was conducted in human transgenic cell line FL-REV3- by 8-azaguanine screening, and mutation occurred on undamaged DNA template was detected by using a shuttle plasmid pZ189 as the probe in human transgenic cell lines 293-REV3- and FL-REV3-. The blockage effect of REV3 was measured by combination of reverse transcription-polymerase chain reaction to detect the expression of antisense REV3 RNA and Western blotting to detect the REV3 protein level.
RESULTS: The human REV3 gene was significantly activated by MNNG treatment, as indicated by the upregulation of REV3 gene expression at the transcriptional level in MNNG-treated human cells, with significant increase of REV3 expression level by 0.38 fold, 0.33 fold and 0.27 fold respectively at 6 h, 12 h and 24 h in MNNG-treated 293 cells (P < 0.05); and to 0.77 fold and 0.65 fold at 12 h and 24 h respectively in MNNG-treated FL cells (P < 0.05). In transgenic cell line (in which REV3 was blocked by antisense REV3 RNA), high level of antisense REV3 RNA was detected, with a decreased level of REV3 protein. MNNG treatment significantly increased the mutation frequencies on undamaged DNA template (untargeted mutation), and also at HPRT locus (lesion-targeted mutation). However, when REV3 gene was blocked by antisense REV3 RNA, the MNNG-induced mutation frequency on undamaged DNA templates was significantly decreased by 3.8 fold (P < 0.05) and 5.8 fold (P < 0.01) respectively both in MNNG-pretreated transgenic 293 cells and FL cells in which REV3 was blocked by antisense RNA, and almost recovered to their spontaneous mutation levels. The spontaneous HPRT mutation was disappeared in REV3-disrupted cells, and induced mutation frequency at HPRT locus significantly decreased from 8.66 × 10-6 in FL cells to 0.14 × 10-6 in transgenic cells as well (P < 0.01).
CONCLUSION: The expression of the human REV3 can be upregulated at the transcriptional level in response to MNNG. The human REV3 gene plays a role not only in lesion-targeted DNA mutagenesis, but also in mutagenesis on undamaged DNA templates that is called untargeted mutation.
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Affiliation(s)
- Feng Zhu
- Department of Pathophysiology, Zhejiang University School of Medicine, Hangzhou 310031, China.
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94
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Yang IY, Miller H, Wang Z, Frank EG, Ohmori H, Hanaoka F, Moriya M. Mammalian translesion DNA synthesis across an acrolein-derived deoxyguanosine adduct. Participation of DNA polymerase eta in error-prone synthesis in human cells. J Biol Chem 2003; 278:13989-94. [PMID: 12584190 DOI: 10.1074/jbc.m212535200] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
alpha-OH-PdG, an acrolein-derived deoxyguanosine adduct, inhibits DNA synthesis and miscodes significantly in human cells. To probe the cellular mechanism underlying the error-free and error-prone translesion DNA syntheses, in vitro primer extension experiments using purified DNA polymerases and site-specific alpha-OH-PdG were conducted. The results suggest the involvement of pol eta in the cellular error-prone translesion synthesis. Experiments with xeroderma pigmentosum variant cells, which lack pol eta, confirmed this hypothesis. The in vitro results also suggested the involvement of pol iota and/or REV1 in inserting correct dCMP opposite alpha-OH-PdG during error-free synthesis. However, none of translesion-specialized DNA polymerases catalyzed significant extension from a dC terminus when paired opposite alpha-OH-PdG. Thus, our results indicate the following. (i) Multiple DNA polymerases are involved in the bypass of alpha-OH-PdG in human cells. (ii) The accurate and inaccurate syntheses are catalyzed by different polymerases. (iii) A modification of the current eukaryotic bypass model is necessary to account for the accurate bypass synthesis in human cells.
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Affiliation(s)
- In-Young Yang
- Laboratory of Chemical Biology, Department of Pharmacological Sciences, State University of New York at Stony Brook, 11794-8651, USA
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95
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Masuda Y, Ohmae M, Masuda K, Kamiya K. Structure and enzymatic properties of a stable complex of the human REV1 and REV7 proteins. J Biol Chem 2003; 278:12356-60. [PMID: 12529368 DOI: 10.1074/jbc.m211765200] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
With yeast Saccharomyces cerevisiae, results from a variety of genetic and biochemical investigations have demonstrated that the REV genes play a major role in induction of mutations through replication processes that directly copy the damaged DNA template during DNA replication. However, in higher eucaryotes functions of homologues are poorly understood and appear somewhat different from the yeast case. It has been suggested that human REV1 interacts with human REV7, this being specific to higher eucaryotes. Here we show that purified human REV1 and REV7 proteins form a heterodimer in solution, which is stable through intensive purification steps. Results from biochemical analysis of the transferase reactions of the REV1-REV7 complex demonstrated, in contrast to the case of yeast Rev3 whose polymerase activity is stimulated by assembly with yeast Rev7, that human REV7 did not influence the stability, substrate specificity, or kinetic parameters of the transferase reactions of REV1 protein. The possible role of human REV7 is discussed.
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Affiliation(s)
- Yuji Masuda
- Research Institute for Radiation Biology and Medicine, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8553, Japan
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96
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Simpson LJ, Sale JE. Rev1 is essential for DNA damage tolerance and non-templated immunoglobulin gene mutation in a vertebrate cell line. EMBO J 2003; 22:1654-64. [PMID: 12660171 PMCID: PMC152905 DOI: 10.1093/emboj/cdg161] [Citation(s) in RCA: 151] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
The majority of DNA damage-induced mutagenesis in the yeast Saccharomyces cerevisiae arises as a result of translesion replication. This process is critically dependent on the deoxycytidyl transferase Rev1p, which forms a complex with the subunits of DNA polymerase zeta, Rev3p and Rev7p. To examine the role of Rev1 in vertebrate mutagenesis and the DNA damage response, we disrupted the gene in DT40 cells. Rev1-deficient DT40 grow slowly and are sensitive to a wide range of DNA-damaging agents. Homologous recombination repair is likely to be intact as basal and damage induced sister chromatid exchange and immunoglobulin gene conversion are unaffected. How ever, the mutant cells show a markedly reduced level of non-templated immunoglobulin gene mutation, indicating a defect in translesion bypass. Furthermore, ultraviolet exposure results in marked chromosome breakage, suggesting that replication gaps created in the absence of Rev1 cannot be efficiently repaired by recombination. Thus, Rev1-dependent translesion bypass and mutagenesis is likely to be a trade-off for the ability to complete replication of a damaged template and thereby maintain genome integrity.
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Affiliation(s)
- Laura J Simpson
- Medical Research Council Laboratory of Molecular Biology, Division of Protein & Nucleic Acid Chemistry, Hills Road, Cambridge CB2 2QH, UK
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97
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Abstract
The newly found Y-family DNA polymerases are characterized by low fidelity replication using an undamaged template and the ability to carry out translesion DNA synthesis. The crystal structures of three Y-family polymerases, alone or complexed with DNA and nucleotide substrate, reveal a conventional right-hand-like catalytic core consisting of finger, thumb and palm domains. The finger and thumb domains are unusually small resulting in an open and spacious active site, which can accommodate mismatched base pairs as well as various DNA lesions. Although devoid of a 3'-->5' exonuclease activity, the Y-family polymerases possess a unique "little finger" domain that facilitates DNA association, catalytic efficiency and interactions with auxiliary factors. Expression of Y-family polymerases is often induced by DNA damage, and their recruitment to the replication fork is mediated by beta-clamp, clamp loader, single-strand-DNA-binding protein and RecA in Escherichia coli, and by ubiquitin-modified proliferating cell nuclear antigen in yeast.
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Affiliation(s)
- Wei Yang
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
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98
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Murakumo Y. The property of DNA polymerase zeta: REV7 is a putative protein involved in translesion DNA synthesis and cell cycle control. Mutat Res 2002; 510:37-44. [PMID: 12459441 DOI: 10.1016/s0027-5107(02)00250-6] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Translesion DNA synthesis (TLS) is an important damage tolerance system which rescues cells from severe injuries caused by DNA damage. Specialized low fidelity DNA polymerases in this system synthesize DNA past lesions on the template DNA strand, that replicative DNA polymerases are usually unable to pass through. However, in compensation for cell survival, most polymerases in this system are potentially mutagenic and sometimes introduce mutations in the next generation. In yeast Saccharomyces cerevisiae (S. cerevisiae), DNA polymerase zeta, which consists of Rev3 and Rev7 proteins, and Rev1 are known to be involved in most damage-induced and spontaneous mutations. The human homologs of S. cerevisiae REV1, REV3, and REV7 were identified, and it is revealed that the human REV proteins have similar functions to their yeast counterparts, however, a large part of the mechanisms of mutagenesis employing REV proteins are still unclear. Recently, the new findings about REV proteins were reported, which showed that REV7 interacts not only with REV3 but also with REV1 in human and that REV7 is involved in cell cycle control in Xenopus. These findings give us a new point of view for further investigation about REV proteins. Recent studies of REV proteins are summarized and several points are discussed.
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Affiliation(s)
- Yoshiki Murakumo
- Department of Pathology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan.
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99
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Li Z, Zhang H, McManus TP, McCormick JJ, Lawrence CW, Maher VM. hREV3 is essential for error-prone translesion synthesis past UV or benzo[a]pyrene diol epoxide-induced DNA lesions in human fibroblasts. Mutat Res 2002; 510:71-80. [PMID: 12459444 DOI: 10.1016/s0027-5107(02)00253-1] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
In S. cerevisiae, the REV3 gene, encoding the catalytic subunit of polymerase zeta, is involved in translesion synthesis and required for the production of mutations induced by ultraviolet radiation (UV) photoproducts and other DNA fork-blocking lesions, and for the majority of spontaneous mutations. To determine whether hREV3, the human homolog of yeast REV3, is similarly involved in error-prone translesion synthesis past UV photoproducts and other lesions that block DNA replication, an hREV3 antisense construct under the control of the TetP promoter was transfected into an infinite life span human fibroblast cell strain that expresses a high level of tTAk, the activator of that promoter. Three transfectant strains expressing high levels of hREV3 antisense RNA were identified and compared with their parental cell strain for sensitivity to the cytotoxic and mutagenic effects of UV. The three hREV3 antisense-expressing cell strains were not more sensitive than the parental strain to the cytotoxic effect of UV, but the frequency of mutants induced by UV in their HPRT gene was significantly reduced, i.e. to 14% that of the parent. Two of these hREV3 antisense-expressing cell strains were compared with the parental strain for sensitivity to (+/-)-7beta,8alpha-dihydroxy-9alpha,10alpha-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene (BPDE). They were not more sensitive than the parent strain to the cytotoxic effect of BPDE, but the frequency of mutants induced was significantly reduced, i.e. in one strain, to 17% that of the parent, and in the other, to 24%. DNA sequencing showed that the kinds of mutations induced by BPDE in the parental and the derivative strains did not differ and were similar to those found previously with finite life span human fibroblasts. The data strongly support the hypothesis that hRev3 plays a critical role in the induction of mutations by UV or BPDE. Because the level of hRev3 protein in human fibroblasts is below the level of antibody detection, it was not possible to demonstrate that the decrease in mutagenesis reflected decreased hRev3 protein. However, the conclusion is supported by the fact that in a similar study with a strain expressing a high level of antisense hREV1, a very similar result was obtained, i.e. UV or BPDE mutagenesis was virtually eliminated.
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Affiliation(s)
- Ziqiang Li
- Carcinogenesis Laboratory, Department of Microbiology and Molecular Genetics, Food Safety and Toxicology Building, Michigan State University, East Lansing, MI 48824-1302, USA
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100
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Cordeiro-Stone M, Nikolaishvili-Feinberg N. Asymmetry of DNA replication and translesion synthesis of UV-induced thymine dimers. Mutat Res 2002; 510:91-106. [PMID: 12459446 DOI: 10.1016/s0027-5107(02)00255-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
In vitro replication assays for detection and quantification of bypass of UV-induced DNA photoproducts were used to compare the capacity of extracts prepared from different human cell lines to replicate past the cis,syn cyclobutane thymine dimer ([c,s]TT). The results demonstrated that neither nucleotide excision repair (NER) nor mismatch repair (MMR) activities in the intact cells interfered with measurements of bypass replication efficiencies in vitro. Extracts prepared from HeLa (NER- and MMR-proficient), xeroderma pigmentosum group A (NER-deficient), and HCT116 (MMR-deficient) cells displayed similar capacity for translesion synthesis, when the substrate carried the site-specific [c,s]TT on the template for the leading or the lagging strand of nascent DNA. Extracts from xeroderma pigmentosum variant cells, which lack DNA polymerase eta, were devoid of bypass activity. Bypass-proficient extracts as a group (n=16 for 3 extracts) displayed higher efficiency (P=0.005) for replication past the [c,s]TT during leading strand synthesis (84+/-22%) than during lagging strand synthesis (64+/-13%). These findings are compared to previous results concerning the bypass of the (6-4) photoproduct [Biochemistry 40 (2001) 15215] and analyzed in the context of the reported characteristics of bypass DNA polymerases implicated in translesion synthesis of UV-induced DNA lesions. Models to explain how these enzymes might interact with the DNA replication machinery are considered. An alternative pathway of bypass replication, which avoids translesion synthesis, and the mutagenic potential of post-replication repair mechanisms that contribute to the duplication of the human genome damaged by UV are discussed.
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Affiliation(s)
- Marila Cordeiro-Stone
- Department of Pathology and Laboratory Medicine, Lineberger Comprehensive Cancer Center, School of Medicine, University of North Carolina,Chapel Hill, NC 27599-7525, USA.
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