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Kraemer KH, DiGiovanna JJ. Global contributions to the understanding of DNA repair and skin cancer. J Invest Dermatol 2014; 134:E8-17. [PMID: 25302472 PMCID: PMC6334767 DOI: 10.1038/skinbio.2014.3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- Kenneth H Kraemer
- Dermatology Branch, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland, USA
| | - John J DiGiovanna
- Dermatology Branch, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland, USA
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2
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Luijsterburg MS, von Bornstaedt G, Gourdin AM, Politi AZ, Moné MJ, Warmerdam DO, Goedhart J, Vermeulen W, van Driel R, Höfer T. Stochastic and reversible assembly of a multiprotein DNA repair complex ensures accurate target site recognition and efficient repair. ACTA ACUST UNITED AC 2010; 189:445-63. [PMID: 20439997 PMCID: PMC2867314 DOI: 10.1083/jcb.200909175] [Citation(s) in RCA: 103] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Computational modeling and quantitative analysis show that although accumulation of repair complexes can take hours, the individual components rapidly exchange between the nucleoplasm and DNA damage sites. To understand how multiprotein complexes assemble and function on chromatin, we combined quantitative analysis of the mammalian nucleotide excision DNA repair (NER) machinery in living cells with computational modeling. We found that individual NER components exchange within tens of seconds between the bound state in repair complexes and the diffusive state in the nucleoplasm, whereas their net accumulation at repair sites evolves over several hours. Based on these in vivo data, we developed a predictive kinetic model for the assembly and function of repair complexes. DNA repair is orchestrated by the interplay of reversible protein-binding events and progressive enzymatic modifications of the chromatin substrate. We demonstrate that faithful recognition of DNA lesions is time consuming, whereas subsequently, repair complexes form rapidly through random and reversible assembly of NER proteins. Our kinetic analysis of the NER system reveals a fundamental conflict between specificity and efficiency of chromatin-associated protein machineries and shows how a trade off is negotiated through reversibility of protein binding.
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3
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Schärer OD. XPG: its products and biological roles. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2008; 637:83-92. [PMID: 19181113 DOI: 10.1007/978-0-387-09599-8_9] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Xeroderma pigmetosum patients of the complementation group G are rare. One group of XP-G patients displays a rather mild and typical XP phenotype. Mutations in these patients interfere with the function of XPG in the nucleotide excision repair, where it has a structural role in the assembly of the preincision complex and a catalytic role in making the incision 3' to the damaged site in DNA. Another set of XP-G patient is much more severely affected, displaying combined symptoms of xeroderma pigmentosum and Cockayne syndrome, referred to as XP/CS complex. Although the molecular basis leading to the XP/CS complex has not yet been fully established, current evidence suggests that these patients suffer from a mild defect in transcription in addition to a repair defect. Here, the history of how the XPG gene was discovered, the biochemical properties of the XPG protein and the molecular defects found in XP-G patients and mouse models are reviewed.
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Affiliation(s)
- Orlando D Schärer
- Department of Pharmacological Sciences and Chemistry, Stony Brook University, Stony Brook, NY 11974-3400, USA.
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4
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Leadon SA. Transcription-coupled repair: a multifunctional signaling pathway. COLD SPRING HARBOR SYMPOSIA ON QUANTITATIVE BIOLOGY 2003; 65:561-6. [PMID: 12760074 DOI: 10.1101/sqb.2000.65.561] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- S A Leadon
- Department of Radiation Oncology, University of North Carolina, Chapel Hill, North Carolina 27599-7512, USA
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5
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Kumar R, Höglund L, Zhao C, Försti A, Snellman E, Hemminki K. Single nucleotide polymorphisms in the XPG gene: determination of role in DNA repair and breast cancer risk. Int J Cancer 2003; 103:671-5. [PMID: 12494477 DOI: 10.1002/ijc.10870] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
In this study we determined the effect of single nucleotide polymorphisms in the XPG gene on DNA repair and breast cancer susceptibility. Ninety individuals, with previously studied DNA repair rate at 24 hr of 2 types of UV-specific cyclobutane pyrimidines dimers (CPDs) in skin were genotyped for XPG polymorphism at codon 1104 (exon 15 G>C; Asp > His). The repair rate of TT=C dimer was similar in both wild-type GG homozygotes and GC heterozygotes, whereas, for TT=T, dimer repair was non-significantly (Student's t-test, p = 0.34) lower in GC heterozygotes than wild-type GG homozygotes. Genotyping of 220 breast cancer cases and 308 controls for the same single nucleotide polymorphism in exon 15 of the XPG gene exhibited marginally significant increased frequency of the variant allele (chi(2) 3.84, p = 0.05; OR 1.33, 95% CI 1.0-1.8) in cases (C-allele 0.29) compared to controls (C-allele 0.24). Combined heterozygote and variant homozygote genotype frequency was also higher in cases than controls (chi(2) 4.79, p = 0.03; OR 1.50, 95%CI 1.04-2.16).
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Affiliation(s)
- Rajiv Kumar
- Department of Biosciences, Center for Nutrition and Toxicology, Karolinska Institute, Novum, Huddinge, Sweden.
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6
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Emmert S, Slor H, Busch DB, Batko S, Albert RB, Coleman D, Khan SG, Abu-Libdeh B, DiGiovanna JJ, Cunningham BB, Lee MM, Crollick J, Inui H, Ueda T, Hedayati M, Grossman L, Shahlavi T, Cleaver JE, Kraemer KH. Relationship of neurologic degeneration to genotype in three xeroderma pigmentosum group G patients. J Invest Dermatol 2002; 118:972-82. [PMID: 12060391 DOI: 10.1046/j.1523-1747.2002.01782.x] [Citation(s) in RCA: 84] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
We studied three newly diagnosed xeroderma pigmentosum complementation group G patients with markedly different clinical features. An Israeli-Palestinian girl (XP96TA) had severe abnormalities suggestive of the xeroderma pigmentosum/Cockayne syndrome complex including sun sensitivity, neurologic and developmental impairment, and death by age 6 y. A Caucasian girl (XP82DC) also had severe sun sensitivity with neurologic and developmental impairment and died at 5.8 y. In contrast, a mildly affected 14-y-old Caucasian female (XP65BE) had sun sensitivity but no neurologic abnormalities. XP96TA, XP82DC, and XP65BE fibroblasts showed marked reductions in post-ultraviolet cell survival and DNA repair but these were higher in XP65BE than in XP82DC. XP96TA fibroblasts had very low XPG mRNA expression levels whereas XP65BE fibroblasts had nearly normal levels. Host cell reactivation of an ultraviolet-treated reporter assigned all three fibroblast strains to the rare xeroderma pigmentosum complementation group G (only 10 other patients previously reported). XP96TA and XP82DC cells had mutations in both XPG alleles that are predicted to result in severely truncated proteins including stop codons and two base frameshifts. The mild XP65BE patient had an early stop codon mutation in the paternal allele. The XP65BE maternal allele had a single base missense mutation (G2817A, Ala874Thr) that showed residual ability to complement xeroderma pigmentosum complementation group G cells. These observations agree with earlier studies demonstrating that XPG mutations, which are predicted to lead to severely truncated proteins in both alleles, were associated with severe xeroderma pigmentosum/Cockayne syndrome neurologic symptoms. Retaining residual functional activity in one allele was associated with mild clinical features without neurologic abnormalities.
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Affiliation(s)
- Steffen Emmert
- Basic Research Laboratory, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland 20892, USA
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7
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Chipchase MD, Melton DW. The formation of UV-induced chromosome aberrations involves ERCC1 and XPF but not other nucleotide excision repair genes. DNA Repair (Amst) 2002; 1:335-40. [PMID: 12509251 DOI: 10.1016/s1568-7864(02)00010-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
ERCC1-XPF, through its role in nucleotide excision repair (NER), is essential for the repair of DNA damage caused by UV light. ERCC1-XPF is also involved in recombinational repair processes distinct from NER. In rodent cells chromosome aberrations are a common consequence of UV irradiation. We have previously shown that ERCC1-deficient cells have a lower ratio of chromatid exchanges to breaks than wild type cells. We have now confirmed this result and have shown that XPF-deficient cells also have a lower ratio than wild type. However, cells deficient in the other NER genes, XPD, XPB and XPG, all have the same ratio of exchanges to breaks as wild type. This implies that ERCC1-XPF, but not other NER proteins, is involved in the formation of UV-induced chromosome aberrations, presumably through the role of ERCC1-XPF in recombinational repair pathways rather than NER. We suggest that ERCC1-XPF may be involved in the bypass/repair of DNA damage in replicating DNA by an exchange mechanism involving single strand annealing between non-homologous chromosomes. This mechanism would rely on the ability of ERCC1-XPF to trim non-homologous 3' tails.
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Affiliation(s)
- Michael D Chipchase
- Sir Alastair Currie Cancer Research UK Laboratories, Molecular Medicine Centre, Western General Hospital, University of Edinburgh, Edinburgh, EH4 2XU, UK
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8
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Lalle P, Nouspikel T, Constantinou A, Thorel F, Clarkson SG. The founding members of xeroderma pigmentosum group G produce XPG protein with severely impaired endonuclease activity. J Invest Dermatol 2002; 118:344-51. [PMID: 11841555 DOI: 10.1046/j.0022-202x.2001.01673.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Of the eight human genes implicated in xeroderma pigmentosum, defects in XPG produce some of the most clinically diverse symptoms. These range from mild freckling to severe skeletal and neurologic abnormalities characteristic of Cockayne syndrome. Mildly affected xeroderma pigmentosum group G patients have diminished XPG endonuclease activity in nucleotide excision repair, whereas severely affected xeroderma pigmentosum group G/Cockayne syndrome patients produce truncated XPG proteins that are unable to function in either nucleotide excision repair or the transcription-coupled repair of oxidative lesions. The first two xeroderma pigmentosum group G patients, XP2BI and XP3BR, were reported before the relationship between xeroderma pigmentosum group G and Cockayne syndrome was appreciated. Here we provide evidence that both patients produce truncated proteins from one XPG allele. From the second allele, XP2BI generates full-length XPG of 1186 amino acids containing a single L858P substitution that has reduced stability and greatly impaired endonuclease activity. In XP3BR, a single base deletion and alternative splicing at a rare noncanonical AT-AC intron produces a 1185 amino acid protein containing 44 internal non-XPG residues. This protein is stably expressed but it also has greatly impaired endonuclease activity. These four XPG products can thus account for the severe ultraviolet sensitivity of XP2BI and XP3BR fibroblasts. These cells, unlike those from xeroderma pigmentosum group G/Cockayne syndrome patients, are capable of limited transcription-coupled repair of oxidative lesions. Our results suggest that the L858P protein in XP2BI and the almost full-length XPG protein in XP3BR are responsible for this activity and for the absence of severe early onset Cockayne syndrome symptoms in these patients.
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Affiliation(s)
- Philippe Lalle
- Department of Genetics and Microbiology, Centre Médical Universitaire (CMU), Geneva, Switzerland
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9
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Leadon SA. Transcription-coupled repair of DNA damage: unanticipated players, unexpected complexities. Am J Hum Genet 1999; 64:1259-63. [PMID: 10205254 PMCID: PMC1377859 DOI: 10.1086/302390] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Affiliation(s)
- S A Leadon
- Department of Radiation Oncology, University of North Carolina, Chapel Hill, NC 27599-7512, USA.
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10
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Okinaka RT, Perez-Castro AV, Sena A, Laubscher K, Strniste GF, Park MS, Hernandez R, MacInnes MA, Kraemer KH. Heritable genetic alterations in a xeroderma pigmentosum group G/Cockayne syndrome pedigree. Mutat Res 1997; 385:107-14. [PMID: 9447232 DOI: 10.1016/s0921-8777(97)00031-1] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
A search for genetic alterations within the XPG gene has been conducted on skin and blood cells cultured from a newly characterized xeroderma pigmentosum (XP) patient (XP20BE). This patient is the ninth known case that falls into the extremely rare XP complementation group G. Four genetic markers within the XPG gene (including two polymorphisms) demonstrated the Mendelian distribution of this gene from the parents to the patient and to an unaffected sibling. The patient (XP20BE) inherited a G to T transversion from his father in exon 1 of the XPG gene that resulted in the conversion of a glutamic acid at codon 11 to a termination codon. The patient also inherited an XP-G allele from his mother that produces an unstable or poorly expressed message. The cause of the latter defect is still uncertain. In addition to these alterations, XP20BE cDNA contained an mRNA species with a large splicing defect that encompassed a deletion from exon 1 to exon 14. This splicing defect, however, appears to be a naturally occurring low-frequency event that results from abnormal splicing that occurs between certain conserved non-consensus splicing signals within the human XPG gene.
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Affiliation(s)
- R T Okinaka
- Life Sciences Division, Los Alamos National Laboratory, NM 87545, USA.
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11
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Park MS, Valdez J, Gurley L, Kim CY. Characterization of a putative helix-loop-helix motif in nucleotide excision repair endonuclease, XPG. J Biol Chem 1997; 272:27823-9. [PMID: 9346928 DOI: 10.1074/jbc.272.44.27823] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Complementation group G of xeroderma pigmentosum (XPG) is one of the most rare and pathophysiologically heterogeneous forms of this inherited disease. XPG patients exhibit varying phenotypes, from having a very mild defect in DNA repair to being severely affected, and a few cases are also associated with the neurological degeneracy and growth retardation of Cockayne's syndrome. The XPG gene encodes a 134-kDa nuclear protein that is essential for the incision steps of nucleotide excision repair. XPG protein contains a putative helix-loop-helix (HLH) motif in the region that is most conserved among the members of structure-specific endonuclease family. To establish the functional significance of the HLH motif, we used several approaches, including theoretical modeling, functional complementation assay, structure-specific endonuclease assay, and DNA binding assay. A secondary structure of the motif was predicted by energy minimization and the Monte Carlo simulation and empirically proven using the circular dichroism to contain a high content of alpha-helix. When an XPG mutant lacking the HLH was overexpressed in UV135 cells, which have defects in the hamster homolog of XPG, the mutant gene failed to confer to the hamster cells the resistance to UV light. A recombinant XPG protein lacking the HLH motif was purified from insect cells and tested for a structure-specific endonuclease activity. The mutant protein failed to cleave the flap strand. A recombinant peptide containing the HLH (amino acids 758-871) was expressed in and purified from bacteria, tested for DNA binding activity, and found to bind to a DNA substrate with the flap structure. These results suggest that the HLH motif is required for the catalytic and DNA binding activities of XPG.
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Affiliation(s)
- M S Park
- Life Sciences Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
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12
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Gary R, Ludwig DL, Cornelius HL, MacInnes MA, Park MS. The DNA repair endonuclease XPG binds to proliferating cell nuclear antigen (PCNA) and shares sequence elements with the PCNA-binding regions of FEN-1 and cyclin-dependent kinase inhibitor p21. J Biol Chem 1997; 272:24522-9. [PMID: 9305916 DOI: 10.1074/jbc.272.39.24522] [Citation(s) in RCA: 179] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Proliferating cell nuclear antigen (PCNA) is a DNA polymerase accessory factor that is required for DNA replication during S phase of the cell cycle and for resynthesis during nucleotide excision repair of damaged DNA. PCNA binds to flap endonuclease 1 (FEN-1), a structure-specific endonuclease involved in DNA replication. Here we report the direct physical interaction of PCNA with xeroderma pigmentosum (XP) G, a structure-specific repair endonuclease that is homologous to FEN-1. We have identified a 28-amino acid region of human FEN-1 (residues 328-355) and a 29-amino acid region of human XPG (residues 981-1009) that contains the PCNA binding activity. These regions share key hydrophobic residues with the PCNA-binding domain of the cyclin-dependent kinase inhibitor p21(Waf1/Cip1), and all three competed with one another for binding to PCNA. A conserved arginine in FEN-1 (Arg339) and XPG (Arg992) was found to be crucial for PCNA binding activity. R992A and R992E mutant forms of XPG failed to fully reconstitute nucleotide excision repair in an in vivo complementation assay. These results raise the possibility of a mechanistic linkage between excision and repair synthesis that is mediated by PCNA.
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Affiliation(s)
- R Gary
- Life Sciences Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
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13
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Bang DD, Ketting R, de Ruijter M, Brandsma JA, Verhage RA, van de Putte P, Brouwer J. Cloning of Schizosaccharomyces pombe rph16+, a gene homologous to the Saccharomyces cerevisiae RAD16 gene. Mutat Res 1996; 364:57-71. [PMID: 8879272 DOI: 10.1016/0921-8777(96)00010-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The RAD16 gene is involved in the nucleotide excision repair of UV damage in the transcriptional silenced mating type loci (Terleth et al., 1990 and Bang et al., 1992) and in non-transcribed stands of active genes in Saccharomyces cerevisiae (Verhage et al., 1994). Using touchdown-PCR with primers derived from various domains of the S. cerevisiae Rad 16 protein, a specific Schizosaccharomyces pombe probe was isolated. This probe was used to obtain the complete RAD16 homologous gene from a S. pombe chromosomal bank. DNA sequence analysis of the rph16+ gene revealed an open reading frame of 854 amino acids. Comparison of the amino acid sequences of the Rhp16 and Rad16 proteins showed a high level of conservation: 68% similarity. The Rhp16 protein sequence contains the two Zn-finger motifs and the putative helicase domains as found in the Rad16 protein. Like the RAD16, the rph16+ gene is UV-inducible (Bang et al., 1995). In analogy with the rad16 mutant, the rhp16 disruption mutant is viable and grows normally, indicating that the gene does not have an essential function. The rhp16 disruption mutant is not sensitive for UV but is sensitive for cisplatin. The rhp16+ gene cloned behind the GAI 1 promoter partially complements the UV sensitivity and the defect in the non-transcribed strand DNA repair of a S. cerevisiae rad16 mutant, indicating functional homology between the rhp16+ and RAD16 genes. The structural and functional homology between the two genes suggests that the RAD16 dependent subpathway of NER for the repair of non-transcribed DNA is evolutionary conserved.
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Affiliation(s)
- D D Bang
- Department of Biochemistry, Leiden Institute of Chemistry, Gorlaeus laboratories, Leiden University, The Netherlands
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14
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Ludwig DL, Mudgett JS, Park MS, Perez-Castro AV, MacInnes MA. Molecular cloning and structural analysis of the functional mouse genomic XPG gene. Mamm Genome 1996; 7:644-9. [PMID: 8703115 DOI: 10.1007/s003359900198] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The mouse XPG gene is a homolog of the human DNA excision repair gene known to be defective in the hereditary sun-sensitive disorder xeroderma pigmentosum (group-G). Defects in mouse XPG have been shown to directly affect the sensitivity of cultured cells to chemotherapy agents and may play a role in tumor cell drug resistance in vivo. A full-length cosmid clone of mouse XPG was isolated by complementation of the UV sensitivity and repair defect in CHO-UV135 cells. Exon mapping determined that the gene consisted of 15 exons within 32 kb of genomic DNA. Sequencing of intron-exon boundaries revealed that mouse XPG possesses a rare class of intron previously identified in only four other eukaryotic genes; it utilizes AT and AC dinucleotides instead of the expected GT and AG within the splice junctions. Promoter analysis determined that mouse XPG is expressed constitutively and probably initiates transcription from multiple start sites, yet, unlike the yeast homolog RAD2, we found no evidence that it is UVC inducible in cultured cells. Amino acid comparison with human XPG identified a highly conserved acidic region of homology not previously described.
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Affiliation(s)
- D L Ludwig
- Life Sciences Division, MS M888, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
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15
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Knauf JA, Pendergrass SH, Marrone BL, Strniste GF, MacInnes MA, Park MS. Multiple nuclear localization signals in XPG nuclease. Mutat Res 1996; 363:67-75. [PMID: 8632779 DOI: 10.1016/0921-8777(95)00062-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
We report here evidence for the mechanism of nuclear localization of XPG nuclease in human cells. Several candidate nuclear localization signal (NLS) peptides have been proposed for XPG protein. We have identified XPG peptides containing functional NLS and a potential nuclear retention signal (NRS) using in situ immunofluorescene localization of transiently expressed beta-galactosidase fusion proteins. Two XPG regions with putative NLS [amino acid (AA) coordinates: NLS-B (AA 1057-1074) and NLS-C (AA 1171-1185)] were each shown to independently localize the beta-gal extensively (> 80%) to the nucleus of HeLa cells. The C-terminus peptide containing NLS-C, an NLS conserved evolutionarily between yeasts and humans, also directed sub-localization of beta-galactosidase to intranuclear foci reminiscent of native XPG protein, as well as to peri-nucleolar regions. Peptides in the putative XPG 'NLS domain' (AA approximately 1051-1185) apparently function in concert for nuclear localization and also for retention of XPG in nuclear matrix-associated foci. Evidence presented elsewhere (Park et al., 1995) indicates that the peptide containing NLS-C (AA 1146-1185) also regulates the dynamic localization of XPG in the nucleus following UV-irradiation.
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Affiliation(s)
- J A Knauf
- Life Sciences Division, Los Alamos National Laboratory, NM 87545, USA
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16
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Shen B, Nolan JP, Sklar LA, Park MS. Essential amino acids for substrate binding and catalysis of human flap endonuclease 1. J Biol Chem 1996; 271:9173-6. [PMID: 8621570 DOI: 10.1074/jbc.271.16.9173] [Citation(s) in RCA: 87] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Human flap endonuclease 1 (FEN-1) is a member of the structure-specific endonuclease family and is involved in DNA repair. Eight restrictively conserved amino acids in FEN-1 have been converted individually to an alanine to elucidate their roles in specific DNA substrate binding and catalysis. Flap endonuclease activity of the wild type and mutant enzymes was measured by kinetic flow cytometry. Mutants D34A, D86A, and D181A lost their cleavage activity completely but retained substrate binding ability, as measured by their ability to inhibit the wild type enzyme in a competition assay. This indicates that these amino acids contribute to integrity of the enzyme active site. Loss of both binding and cleavage competency for the flap substrate by mutants E156A, G231A, and D233A suggests that these amino acids are involved in substrate binding. Mutants R103A and D179A retained wild type-like enzyme activity.
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Affiliation(s)
- B Shen
- Life Sciences Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
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17
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Ma L, Hoeijmakers JH, van der Eb AJ. Mammalian nucleotide excision repair. BIOCHIMICA ET BIOPHYSICA ACTA 1995; 1242:137-63. [PMID: 7492568 DOI: 10.1016/0304-419x(95)00008-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Affiliation(s)
- L Ma
- Department of Medical Biochemistry, Leiden University, The Netherlands
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18
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Abstract
Biochemically active human DNA repair protein, xeroderma pigmentosum G (XPG), was overexpressed in insect cells by a recombinant baculovirus. The recombinant baculovirus produced XPG with a mobility of approximately 185 kDa in a denaturing polyacrylamide gel. Indirect immunofluorescence studies demonstrated that the recombinant full-length XPG protein was expressed predominantly as a nuclear protein. The recombinant XPG protein was purified to apparent homogeneity using Q-sepharose, S-300 size exclusion, and Mono Q column chromatography. XPG protein showed a structure-specific DNA endonuclease activity, and a preferential affinity to single-stranded DNA and RNA compared to double-stranded DNA.
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Affiliation(s)
- K G Cloud
- Life Sciences Division, Los Alamos National Laboratory, NM 87545, USA
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19
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Wood RD. Proteins that participate in nucleotide excision repair of DNA in mammalian cells. Philos Trans R Soc Lond B Biol Sci 1995; 347:69-74. [PMID: 7746857 DOI: 10.1098/rstb.1995.0011] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The most versatile strategy for repair of damage to DNA, and the main process for repair of UV-induced damage, is nucleotide excision repair. In mammalian cells, the complete mechanism involves more than 20 polypeptides, and defects in many of these are associated with various forms of inherited disorders in humans. The syndrome xeroderma pigmentosum (XP) is associated with mutagen hypersensitivity and increased cancer frequency, and studies of the nucleotide excision repair defect in this disease have been particularly informative. Many of the XP proteins are now being characterized. XPA binds to DNA, with a preference for damaged base pairs. XPC activity is part of a protein complex with single-stranded DNA binding activity. The XPG protein is a nuclease.
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Affiliation(s)
- R D Wood
- Imperial Cancer Research Fund, Clare Hall Laboratories, South Mimms, Herts, U.K
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20
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Affiliation(s)
- K S Sweder
- Department of Biological Sciences, Stanford University, CA 94305-5020, USA
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21
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O'Donovan A, Davies AA, Moggs JG, West SC, Wood RD. XPG endonuclease makes the 3' incision in human DNA nucleotide excision repair. Nature 1994; 371:432-5. [PMID: 8090225 DOI: 10.1038/371432a0] [Citation(s) in RCA: 366] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Humans with a defect in the XPG protein suffer from xeroderma pigmentosum (XP) resulting from an inability to perform DNA nucleotide excision repair properly. Here we show that XPG makes a structure-specific endonucleolytic incision in a synthetic DNA substrate containing a duplex region and single-stranded arms. One strand of the duplex is cleaved at the border with single-stranded DNA. A cut with the same polarity is also made in a bubble structure, at the 3' side of the centrally unpaired region. Normal cell extracts introduce a nick 3' to a platinum-DNA lesion, but an XP-G cell extract is defective in making this incision. These data show that XPG has a direct role in making one of the incisions required to excise a damaged oligonucleotide, by cleaving 3' to DNA damage during nucleotide excision repair.
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Affiliation(s)
- A O'Donovan
- Imperial Cancer Research Fund, Clare Hall Laboratories, South Mimms, Herts, UK
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Kelner MJ, McMorris TC, Estes L, Rutherford M, Montoya M, Goldstein J, Samson K, Starr R, Taetle R. Characterization of illudin S sensitivity in DNA repair-deficient Chinese hamster cells. Unusually high sensitivity of ERCC2 and ERCC3 DNA helicase-deficient mutants in comparison to other chemotherapeutic agents. Biochem Pharmacol 1994; 48:403-9. [PMID: 8053936 DOI: 10.1016/0006-2952(94)90113-9] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Illudins, novel natural products with a structure unrelated to any other known chemical, display potent in vitro and in vivo anti-cancer activity against even multi-drug resistant tumors, and are metabolically activated to an unstable intermediate that binds to DNA. The DNA damage produced by illudins, however, appears to differ from that of other known DNA damaging toxins. The sensitivity pattern of the various UV-sensitive cell lines differs from previously studied DNA cross-linking agents. Normally, the ERCC1- (excision repair cross complementing) and ERCC4-deficient cell lines are most sensitive to DNA cross-linking agents, with ERCC2-, ERCC3- and ERCC5-deficient cell lines having minimal sensitivity. With illudins the pattern is reversed, with ERCC2 and ERCC3 being the most sensitive. The sensitivity to illudins in complementation groups 1 through 3 is due to a deficiency of the ERCC1-3 gene products, as cellular drug accumulation studies revealed no differences in transport capacity or total drug accumulation. Also, a transgenic cell line in which ERCC2 activity was expressed through an expression vector regained its relative resistance to the illudins. The EM9 cell line, which displays sensitivity to monoadduct producing chemicals, was not sensitive. Thus, excision repair is involved in repair of illudin-induced damage and, unlike other anti-cancer agents, the involvement of ERCC2 and ERCC3 helicases is critical for repair to occur. The requirement for ERCC2 and ERCC3, combined with the finding that ERCC1 but not ERCC2 is upregulated in drug-resistant tumors, may explain the efficacy of illudins against drug-resistant tumors. The inhibition of DNA synthesis in cells within minutes after exposure to illudins at nanomolar concentrations may be related to the finding that the ERCC3 gene product is actually the p89 helicase component of the BTF2 (TFII) basic transcription factor and the high sensitivity of ERCC3-deficient cells to illudins.
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Affiliation(s)
- M J Kelner
- Department of Pathology, University of California, San Diego 92103-8320
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Lehmann AR, Bootsma D, Clarkson SG, Cleaver JE, McAlpine PJ, Tanaka K, Thompson LH, Wood RD. Nomenclature of human DNA repair genes. Mutat Res 1994; 315:41-2. [PMID: 7517009 DOI: 10.1016/0921-8777(94)90026-4] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Affiliation(s)
- A R Lehmann
- MRC Cell Mutation Unit, University of Sussex, Falmer, Brighton, UK
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O'Donovan A, Scherly D, Clarkson S, Wood R. Isolation of active recombinant XPG protein, a human DNA repair endonuclease. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(17)33956-x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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Aboussekhra A, Wood RD. Repair of UV-damaged DNA by mammalian cells and Saccharomyces cerevisiae. Curr Opin Genet Dev 1994; 4:212-20. [PMID: 8032198 DOI: 10.1016/s0959-437x(05)80047-4] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Cells use many strategies to repair genomic damage caused by environmental agents and arising from the natural instability of the polynucleotide structure. Nucleotide excision repair is the most versatile DNA repair pathway and is the main defense of mammalian cells against UV-induced DNA damage. Defects in proteins involved in this pathway can lead to inherited disorders (such as xeroderma pigmentosum, Cockayne's syndrome and trichothiodystrophy) that are associated with hypersensitivity to sunlight. Most of the proteins and genes involved in these syndromes have now been identified. Study of UV-sensitive yeast RAD mutants has greatly aided this process and has revealed strong conservation of the components of nucleotide excision repair in eukaryotes. It has recently become clear that some of the proteins involved in the DNA repair process have dual functions and also participate in basal transcription and DNA replication.
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Affiliation(s)
- A Aboussekhra
- Imperial Cancer Research Fund, Clare Hall Laboratories, South Mimms, Hertfordshire, UK
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