DOCSLIB.ORG

Mutations in the XPC Gene in Families with Xeroderma Pigmentosum and Consequences at the Cell, Protein, and Transcript Levels1

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Mutations in the XPC Gene in Families with Xeroderma Pigmentosum and Consequences at the Cell, Protein, and Transcript Levels1 [CANCER RESEARCH 60, 1974–1982, April 1, 2000] Mutations in the XPC Gene in Families with Xeroderma Pigmentosum and Consequences at the Cell, Protein, and Transcript Levels1 Franz Chavanne, Bernard C. Broughton, Daniela Pietra, Tiziana Nardo, Alison Browitt, Alan R. Lehmann, and Miria Stefanini2 Istituto di Genetica Biochimica ed Evoluzionistica CNR, 27100 Pavia, Italy [F. C., D. P., T. N., M. S.], and MRC Cell Mutation Unit, Sussex University, Falmer, Brighton BN1 9RR, United Kingdom [B. C. B., A. B., A. R. L.] ABSTRACT (3). The patients from this group usually show only skin disorders and no neurological abnormalities. Cultured fibroblasts from XP-C pa- Xeroderma pigmentosum (XP)-C is one of the more common comple- tients exhibit very limited UV-induced DNA repair synthesis levels, mentation groups of XP, but causative mutations have thus far been ranging between 10 and 20% of normal, and are specifically defective reported for only six cases (S. G. Khan et al., J. Investig. Dermatol., 115: 791–796, 1998; L. Li et al., Nat. Genet., 5: 413–417, 1993). We have now in GGR. They are, however, capable of removing damage from the extended this analysis by investigating the genomic and coding sequence of transcribed strand of active genes at normal rates (4–6). the XPC gene, the level of expression of the XPC transcript and the status Phenotypic correction of XP-C cells by cDNA transfection resulted of the XPC protein in 12 unrelated patients, including all of the 8 Italian in the cloning of a partial but fully active XPC cDNA (7). The XP-C cases identified thus far and in 13 of their parents. Eighteen full-length cDNA, isolated by Masutani et al. (8), is 3558 nts long and mutations were detected in the open reading frame of the XPC gene, 13 of the encoded 940-amino-acid product shows limited homology with which are relevant for the pathological phenotype. The mutations are the Rad4 protein of Saccharomyces cerevisiae. The human XPC gene distributed across the gene, with no indication of any hotspots or founder spans about 24 kb, the transcribed sequence being divided into 15 effects. Only 1 of the 13 relevant changes is a missense mutation, the exons (9). remainder causing protein truncations as a result of nonsense mutations Masutani et al. (8) showed that the XPC gene encodes a M 125,000 (3), frameshifts (6), deletion (1) or splicing abnormalities (2). These find- r ings indicate that the XPC gene is not essential for cell proliferation and protein that is present in a tight complex with the Mr 58,000 protein viability and that mutations causing minor structural alterations may not encoded by hHR23B, one of the two human homologues of the yeast give an XP phenotype and may not, therefore, be identified clinically. RAD23 gene. Almost all of the XPC molecules appear to be com- XP13PV was the only patient carrying a missense mutation (Trp690Ser on plexed in vivo with hHR23B. Recent studies have shown that XPC- the paternal allele). This was also the only patient in which the XPC hHR23B binds to a variety of NER lesions and carries out the first transcript was present at a normal level and the XPC protein was detect- step in NER (damage recognition) in transcriptionally inactive DNA able, although at a lower than normal level. No quantitative alterations in (10, 11). the transcript or protein levels were detected in the XP-C heterozygous Characterization of the molecular defects in XP-C patients may parents. However, the expression of the normal allele predominated in all provide a tool to define further the biological role of the XPC protein, of them, except the father of XP13PV, which suggests the existence of a as well as the sites relevant for its activity. Thus far, six XP-C cell possible mechanism for monitoring the amount of the XPC protein. lines have been characterized at the cDNA level, and eight mutations including point mutations, deletions and insertions have been de- INTRODUCTION scribed (12, 13). In this report, we describe the clinical features and the cellular 3 NER is the principal pathway for removal of a broad spectrum of phenotype of 12 XP-C patients (8 from Italy, 1 from the United structurally unrelated lesions such as UV-induced cyclobutane pyrim- Kingdom, and 3 of Middle Eastern origin), as well as the mutations idine dimers and 6–4 photoproducts, and numerous chemical adducts. detected in the genomic and coding sequence of the XPC gene. For the The NER system has two distinct subpathways: (a) TCR, which Italian patients, the molecular analysis was extended to the parents to rapidly removes lesions from the transcribed strand of active genes; determine the allele inheritance and the linkage relationship of muta- and (b) GGR, which effects the slower repair of the rest of the genome tions. We have also investigated the level of expression of the XPC (recently reviewed in Ref. 1). Defects in NER have been found in transcript by Northern analysis and the occurrence of the XPC protein association with three rare human autosomal recessive syndromes, by Western analysis. which include XP. XP is clinically characterized by extreme sensitiv- ity to sun-exposure, sunlight-induced pigmentation abnormalities, and MATERIALS AND METHODS a high incidence of skin cancer (2). Progressive neurological degen- eration is found in a proportion of patients. Case Reports. The study was performed on 12 patients showing clinical Complementation tests by cell fusion have provided evidence for symptoms typical of XP and classified by genetic analysis into the XP-C the existence of at least seven NER-deficient complementation group. The 8 patients coded with the suffix PV represent all of the XP-C cases groups: XP-A to XP-G. XP group C is one of the more common forms identified in Italy thus far. XP4BR is a typical XP-C patient of Middle Eastern origin (14). XP4RO is of historical interest as it was the first XP to be used in complementation analysis (15). XP6BR is a very unusual patient, who, at the Received 9/23/99; accepted 2/2/00. The costs of publication of this article were defrayed in part by the payment of page age of 67, had had multiple self-healing melanomas (16). XP14BR was charges. This article must therefore be hereby marked advertisement in accordance with unusual in that, apart from the expected sensitivity to UV light, both the 18 U.S.C. Section 1734 solely to indicate this fact. individual and her cells were sensitive to ionizing radiation. Clinical features 1 Supported by Associazione Italiana Ricerca sul Cancro Grant (to M. S.), by EC and related literature references for all of the patients are reported in Table 1. Human Capital and Mobility Grant CHRX-CT94-0443 (to M. S. and A. R. L.), and by EC contract QLG1-1999-00181. In common with most XP-C individuals described in the literature, none of the 2 To whom requests for reprints should be addressed, at Istituto di Genetica Biochimica analyzed cases showed neurological abnormalities. ed Evoluzionistica CNR, via Abbiategrasso 207, 27100 Pavia, Italy. Phone: 39-0382- Cells and Culture Conditions. Primary fibroblast cultures were estab- 546330; Fax: 39-0382-422286; E-mail: [email protected]. lished from biopsies of unaffected skin obtained from the 12 patients and 11 3 The abbreviations used are: NER, nucleotide excision repair; TCR, transcription- coupled repair; GGR, global genome repair; XP, xeroderma pigmentosum; UDS, unsched- parents. Fibroblasts were routinely grown in Ham’s F-10 medium (Life Tech- uled DNA synthesis; nt, nucleotide. nologies, Inc., Rockville, MD) supplemented with 12% FCS (Irvine, Santa 1974 Downloaded from cancerres.aacrjournals.org on September 26, 2021. © 2000 American Association for Cancer Research. GENOTYPE-PHENOTYPE RELATIONSHIPS IN XP-C Table 1 Clinical features and DNA repair data of the 12 XP-C patients analyzed in this study Ocular Age at last Skin Age at Repair synthesis Patient Sex examination (yr) tumors onset (yr) Lesions Tumors (% of normal) Reference XP5PV M 21 ϩ 12 ϩϪc 15 This article XP9PVa M35 ϩ 15 ϩϩ 15 37 XP10PV F 15b ϩ 4 ϩϩ 20 This article XP12PV M 5 ϪϪϪ20 This article XP13PV M 14 ϩ 4 ϩϪ 20 This article XP18PVa F9 ϩ 8 ϪϪ 18 This article XP19PV M 4 ϪϩϪ20 This article XP26PV M 3 ϪϪϪ10 This article XP4RO F 16 ϩ 10 15 XP4BR M 13 ϩ 20 14 XP6BR M 67 ϩ 28 10 16 XP14BR F 19b ϩ 11 Ϫ 10 38 a Parents are consanguineous. b Age at death. c Ϫ, symptoms not present. Ana, CA) or Eagle’s MEM (Life Technologies, Inc.) supplemented with 15% Northern Blot Analysis. RNA was extracted by a cesium chloride-gradi- FCS (PAA Laboratories, Teddington, United Kingdom). Fibroblasts from eight ent centrifugation procedure from samples of 2 ϫ 107 fibroblasts or 1 ϫ 108 healthy donors (C1PV, C3PV, B119, CF, FB345, FB377, FB380, FB383) and lymphoblastoid cells resuspended in 1 ml of guanidinium thiocyanate buffer [4 from two XP patients previously assigned to group C were used as reference M guanidinium thiocyanate and 3 M sodium acetate (pH 6)]. strains in the study. Total RNA (5 ␮g) was electrophoresed on 1.2% agarose formaldehyde gel, Lymphoblastoid cell lines were established by EBV transformation of stained with ethidium bromide, and blotted onto Hybond-N membrane (Am- peripheral blood lymphocytes from a normal donor (352/96), XP26PV, and the ersham). Hybridization was carried out by overnight incubation with an XPC parents of the latter. These cell lines were cultured in RPMI 1640 (Sigma, St. probe corresponding to cDNA nts 286-1413.
Load more

Recommended publications
  • Structure and Function of the Human Recq DNA Helicases
    Zurich Open Repository and Archive University of Zurich Main Library Strickhofstrasse 39 CH-8057 Zurich www.zora.uzh.ch Year: 2005 Structure and function of the human RecQ DNA helicases Garcia, P L Posted at the Zurich Open Repository and Archive, University of Zurich ZORA URL: https://doi.org/10.5167/uzh-34420 Dissertation Published Version Originally published at: Garcia, P L. Structure and function of the human RecQ DNA helicases. 2005, University of Zurich, Faculty of Science. Structure and Function of the Human RecQ DNA Helicases Dissertation zur Erlangung der naturwissenschaftlichen Doktorw¨urde (Dr. sc. nat.) vorgelegt der Mathematisch-naturwissenschaftlichen Fakultat¨ der Universitat¨ Z ¨urich von Patrick L. Garcia aus Unterseen BE Promotionskomitee Prof. Dr. Josef Jiricny (Vorsitz) Prof. Dr. Ulrich H ¨ubscher Dr. Pavel Janscak (Leitung der Dissertation) Z ¨urich, 2005 For my parents ii Summary The RecQ DNA helicases are highly conserved from bacteria to man and are required for the maintenance of genomic stability. All unicellular organisms contain a single RecQ helicase, whereas the number of RecQ homologues in higher organisms can vary. Mu- tations in the genes encoding three of the five human members of the RecQ family give rise to autosomal recessive disorders called Bloom syndrome, Werner syndrome and Rothmund-Thomson syndrome. These diseases manifest commonly with genomic in- stability and a high predisposition to cancer. However, the genetic alterations vary as well as the types of tumours in these syndromes. Furthermore, distinct clinical features are observed, like short stature and immunodeficiency in Bloom syndrome patients or premature ageing in Werner Syndrome patients. Also, the biochemical features of the human RecQ-like DNA helicases are diverse, pointing to different roles in the mainte- nance of genomic stability.
    [Show full text]
  • Open Full Page
    CCR PEDIATRIC ONCOLOGY SERIES CCR Pediatric Oncology Series Recommendations for Childhood Cancer Screening and Surveillance in DNA Repair Disorders Michael F. Walsh1, Vivian Y. Chang2, Wendy K. Kohlmann3, Hamish S. Scott4, Christopher Cunniff5, Franck Bourdeaut6, Jan J. Molenaar7, Christopher C. Porter8, John T. Sandlund9, Sharon E. Plon10, Lisa L. Wang10, and Sharon A. Savage11 Abstract DNA repair syndromes are heterogeneous disorders caused by around the world to discuss and develop cancer surveillance pathogenic variants in genes encoding proteins key in DNA guidelines for children with cancer-prone disorders. Herein, replication and/or the cellular response to DNA damage. The we focus on the more common of the rare DNA repair dis- majority of these syndromes are inherited in an autosomal- orders: ataxia telangiectasia, Bloom syndrome, Fanconi ane- recessive manner, but autosomal-dominant and X-linked reces- mia, dyskeratosis congenita, Nijmegen breakage syndrome, sive disorders also exist. The clinical features of patients with DNA Rothmund–Thomson syndrome, and Xeroderma pigmento- repair syndromes are highly varied and dependent on the under- sum. Dedicated syndrome registries and a combination of lying genetic cause. Notably, all patients have elevated risks of basic science and clinical research have led to important in- syndrome-associated cancers, and many of these cancers present sights into the underlying biology of these disorders. Given the in childhood. Although it is clear that the risk of cancer is rarity of these disorders, it is recommended that centralized increased, there are limited data defining the true incidence of centers of excellence be involved directly or through consulta- cancer and almost no evidence-based approaches to cancer tion in caring for patients with heritable DNA repair syn- surveillance in patients with DNA repair disorders.
    [Show full text]
  • Identification of Novel Pathogenic MSH2 Mutation and New DNA Repair Genes Variants: Investigation of a Tunisian Lynch Syndrome F
    Jaballah‑Gabteni et al. J Transl Med (2019) 17:212 https://doi.org/10.1186/s12967‑019‑1961‑9 Journal of Translational Medicine RESEARCH Open Access Identifcation of novel pathogenic MSH2 mutation and new DNA repair genes variants: investigation of a Tunisian Lynch syndrome family with discordant twins Amira Jaballah‑Gabteni1,3* , Haifa Tounsi1,3, Maria Kabbage1,3, Yosr Hamdi3, Sahar Elouej3,4, Ines Ben Ayed1,3, Mouna Medhioub2, Moufda Mahmoudi2, Hamza Dallali3, Hamza Yaiche1,3, Nadia Ben Jemii1,3, Affa Maaloul1, Najla Mezghani1,3, Sonia Abdelhak3, Lamine Hamzaoui2, Mousaddak Azzouz2 and Samir Boubaker1,3 Abstract Background: Lynch syndrome (LS) is a highly penetrant inherited cancer predisposition syndrome, characterized by autosomal dominant inheritance and germline mutations in DNA mismatch repair genes. Despite several genetic variations that have been identifed in various populations, the penetrance is highly variable and the reasons for this have not been fully elucidated. This study investigates whether, besides pathogenic mutations, environment and low penetrance genetic risk factors may result in phenotype modifcation in a Tunisian LS family. Patients and methods: A Tunisian family with strong colorectal cancer (CRC) history that fulfll the Amsterdam I criteria for the diagnosis of Lynch syndrome was proposed for oncogenetic counseling. The index case was a man, diagnosed at the age of 33 years with CRC. He has a monozygotic twin diagnosed at the age of 35 years with crohn disease. Forty‑seven years‑old was the onset age of his paternal uncle withCRC. An immunohistochemical (IHC) labe‑ ling for the four proteins (MLH1, MSH2, MSH6 and PMS2) of the MisMatchRepair (MMR) system was performed for the index case.
    [Show full text]
  • Arsenic Disruption of DNA Damage Responses—Potential Role in Carcinogenesis and Chemotherapy
    Biomolecules 2015, 5, 2184-2193; doi:10.3390/biom5042184 OPEN ACCESS biomolecules ISSN 2218-273X www.mdpi.com/journal/biomolecules/ Review Arsenic Disruption of DNA Damage Responses—Potential Role in Carcinogenesis and Chemotherapy Clarisse S. Muenyi 1, Mats Ljungman 2 and J. Christopher States 3,* 1 Department of Pharmacology and Toxicology, University of Louisville School of Medicine, Louisville, KY 40292, USA; E-Mail: [email protected] 2 Departments of Radiation Oncology and Environmental Health Sciences, University of Michigan, Ann Arbor, MI 48109-2800, USA; E-Mail: [email protected] 3 Department of Pharmacology and Toxicology, University of Louisville School of Medicine, Louisville, KY 40292, USA * Author to whom correspondence should be addressed; E-Mail: [email protected]; Tel.: +1-502-852-5347; Fax: +1-502-852-3123. Academic Editors: Wolf-Dietrich Heyer, Thomas Helleday and Fumio Hanaoka Received: 14 August 2015 / Accepted: 9 September 2015 / Published: 24 September 2015 Abstract: Arsenic is a Class I human carcinogen and is widespread in the environment. Chronic arsenic exposure causes cancer in skin, lung and bladder, as well as in other organs. Paradoxically, arsenic also is a potent chemotherapeutic against acute promyelocytic leukemia and can potentiate the cytotoxic effects of DNA damaging chemotherapeutics, such as cisplatin, in vitro. Arsenic has long been implicated in DNA repair inhibition, cell cycle disruption, and ubiquitination dysregulation, all negatively impacting the DNA damage response and potentially contributing to both the carcinogenic and chemotherapeutic potential of arsenic. Recent studies have provided mechanistic insights into how arsenic interferes with these processes including disruption of zinc fingers and suppression of gene expression.
    [Show full text]
  • Clinical Significance of ERCC2, XPC, ERCC5 and XRCC3 Gene Polymorphisms in Diffuse Large B Cell Lymphoma
    DOI: 10.14744/ejmi.2020.56831 EJMI 2020;4(3):332–340 Research Article Clinical Significance of ERCC2, XPC, ERCC5 and XRCC3 Gene Polymorphisms in Diffuse Large B Cell Lymphoma Aykut Bahceci,1 Semra Paydas,2 Melek Ergin,3 Gulsah Seydaoglu,4 Gulsum Ucar5 1Department of Medical Oncology, Dr. Ersin Arslan Training and Research Hospital, Gaziantep, Turkey 2Department of Medical Oncology, Cukurova University Faculty of Medicine, Adana, Turkey 3Department of Patology, Cukurova University Faculty of Medicine, Adana, Turkey 4Department of Biostatistics, Cukurova University Faculty of Medicine, Adana, Turkey 5Department of Pediatric Hematology, Cukurova University Faculty of Medicine, Adana, Turkey Abstract Objectives: DNA repair genes protects the genome from DNA damage both of endogenous and exogenous stress fac- tors. Due to DNA repair gene polymorphisms, there are differences in the repair capacity between several cancer types. The aim of this study is to evaluate the association between some of the DNA repair gene polymorphisms and clinical outcome in Diffuse Large B-Cell Lymphoma (DLBCL). Methods: The association between clinical factors including stage at diagnosis, extra-nodal involvement, tumor bur- den, bone marrow involvement, relapse status, disease-free/overall survival times and DNA repair gene polymorphisms including ERCC2 (Lys751Gln), XPC (Gln939Lys), ERCC5 (Asp1104His) and XRCC3 (Thr241Met) in 58 patients with DLBCL. T-Shift Real-Time PCR was used to detect these mutations. Results: The median survival times were 60 months and 109 months in patients with CC genotype and CA/AA geno- type of XPC gene polymorphism, respectively (p=0.017). More interestingly, median survival times were 9 months and 109 months in patients with CC (XPC)/CC (XRCC3) and CA/AA (XPC)/CT/TT (XRCC3) for both XPC and XRCC3 gene polymorphisms, respectively (p=0.004).
    [Show full text]
  • Haplotype Patterns in Cancer-Related Genes with Long-Range Linkage Disequilibrium: No Evidence of Association with Breast Cancer Or Positive Selection
    European Journal of Human Genetics (2008) 16, 252–260 & 2008 Nature Publishing Group All rights reserved 1018-4813/08 $30.00 www.nature.com/ejhg ARTICLE Haplotype patterns in cancer-related genes with long-range linkage disequilibrium: no evidence of association with breast cancer or positive selection Gloria Ribas*,1, Roger L Milne2, Anna Gonzalez-Neira2 and Javier Benı´tez1,2 1Human Genetics Group, Human Cancer Genetics Programme, Spanish National Cancer Centre (CNIO), Madrid, Spain; 2National Genotyping Centre (CeGen), Human Cancer Genetics Programme, Spanish National Cancer Centre (CNIO), Madrid, Spain The average length of linkage disequilibrium (LD) blocks in European populations is about 22 kb. In this study, we have selected 20 genes with LD blocks larger than 60 kb (with a median length of 88 kb) from a total of 121 cancer-related genes. We observed limited haplotype diversity, with an average of three haplotypes per gene accounting for more than 90% of the diversity, two of these being a Yin–Yang pair in 95% of the LD blocks. The mean frequency of the most common haplotype in the Spanish population was just below 50%, similar to those for the HapMap CEU and African samples, but lower than the 60% observed in Asian samples. Genes involved in the regulation of nucleobases and nucleic acid metabolism were overrepresented among these 20 genes with long LD blocks (eight genes ATM, BRCA1, BRCA2, ERCC6, MLH1, MSH3, RAD54B and XRCC4) relative to the other 101 cancer-related genes studied (P ¼ 1.23 Â 10À6). The ancestral haplotype was observed at a frequency greater than 3 in 67% of the genes either in the Spanish or one of the HapMap sampled populations.
    [Show full text]
  • Repair of Damaged and Mismatched DNA by the XPC Homologues Rhp41 and Rhp42 of Fission Yeast
    Copyright 2003 by the Genetics Society of America Repair of Damaged and Mismatched DNA by the XPC Homologues Rhp41 and Rhp42 of Fission Yeast Thomas M. Marti,* Christophe Kunz† and Oliver Fleck*,1 *Institute of Cell Biology, University of Bern, CH-3012 Bern, Switzerland and †Institute of Medical Radiobiology, University of Zu¨rich, CH-8008 Zu¨rich, Switzerland Manuscript received November 26, 2002 Accepted for publication February 20, 2003 ABSTRACT Rhp41 and Rhp42 of Schizosaccharomyces pombe are homologues of human XPC, which is involved in nucleotide excision repair (NER) of damaged DNA. Inactivation of rhp41 caused moderate sensitivity to ultraviolet (UV) radiation. In addition, an increase of mitotic mutation rates was observed in the rhp41 mutant, which was dependent on active translesion polymerase Z. UV sensitivity and mutation rates were not different between rhp42 and wild type, but compared to rhp41 were further increased in rhp41 rhp42 cells. Transcription of the fbp1 gene (induced in vegetative cells) and of the SPBC1289.14 gene (induced during meiosis) was strongly blocked by UV-induced damages in the rhp41 mutant, but not, or only slightly, reduced in rhp42 background. NER-dependent short-patch repair of mismatches formed during meiosis was slightly affected in rhp41, moderately affected in rhp42, and absent in rhp41 rhp42. Epistasis analysis with rhp7 and rhp26 indicates that Rhp41 and Rhp42 are both involved in the global genome and transcrip- tion-coupled repair subpathways of NER. Rhp41 plays a major role in damage repair and Rhp42 in mismatch repair. UCLEOTIDE excision repair (NER) is directed is released in a 24- to 32-nucleotide-long oligonucleotide N to a wide variety of DNA damages, including pho- (Huang et al.
    [Show full text]
  • Understanding Nucleotide Excision Repair and Its Roles in Cancer and Ageing
    REVIEWS DNA DAMAGE Understanding nucleotide excision repair and its roles in cancer and ageing Jurgen A. Marteijn*, Hannes Lans*, Wim Vermeulen, Jan H. J. Hoeijmakers Abstract | Nucleotide excision repair (NER) eliminates various structurally unrelated DNA lesions by a multiwise ‘cut and patch’-type reaction. The global genome NER (GG‑NER) subpathway prevents mutagenesis by probing the genome for helix-distorting lesions, whereas transcription-coupled NER (TC‑NER) removes transcription-blocking lesions to permit unperturbed gene expression, thereby preventing cell death. Consequently, defects in GG‑NER result in cancer predisposition, whereas defects in TC‑NER cause a variety of diseases ranging from ultraviolet radiation‑sensitive syndrome to severe premature ageing conditions such as Cockayne syndrome. Recent studies have uncovered new aspects of DNA-damage detection by NER, how NER is regulated by extensive post-translational modifications, and the dynamic chromatin interactions that control its efficiency. Based on these findings, a mechanistic model is proposed that explains the complex genotype–phenotype correlations of transcription-coupled repair disorders. The integrity of DNA is constantly threatened by endo­ of an intricate DNA-damage response (DDR), which genously formed metabolic products and by-products, comprises sophisticated repair and damage signalling such as reactive oxygen species (ROS) and alkylating processes. The DDR involves DNA-damage sensors and agents, and by its intrinsic chemical instability (for exam­ signalling kinases that regulate a range of downstream ple, by its ability to spontaneously undergo hydrolytic mediator and effector molecules that control repair, cell deamination and depurination). Environmental chemi­ cycle progression and cell fate4. The core of this DDR is cals and radiation also affect the physical constitution of formed by a network of complementary DNA repair sys­ DNA1.
    [Show full text]
  • Involvement of Nucleotide Excision and Mismatch Repair Mechanisms in Double Strand Break Repair
    250 Current Genomics, 2009, 10, 250-258 Involvement of Nucleotide Excision and Mismatch Repair Mechanisms in Double Strand Break Repair Ye Zhang1,2,*, Larry H. Rohde2 and Honglu Wu1 1NASA Johnson Space Center, Houston, Texas 77058 and 2University of Houston at Clear Lake, Houston, Texas 77058, USA Abstract: Living organisms are constantly threatened by environmental DNA-damaging agents, including UV and ioniz- ing radiation (IR). Repair of various forms of DNA damage caused by IR is normally thought to follow lesion-specific re- pair pathways with distinct enzymatic machinery. DNA double strand break is one of the most serious kinds of damage induced by IR, which is repaired through double strand break (DSB) repair mechanisms, including homologous recombi- nation (HR) and non-homologous end joining (NHEJ). However, recent studies have presented increasing evidence that various DNA repair pathways are not separated, but well interlinked. It has been suggested that non-DSB repair mecha- nisms, such as Nucleotide Excision Repair (NER), Mismatch Repair (MMR) and cell cycle regulation, are highly involved in DSB repairs. These findings revealed previously unrecognized roles of various non-DSB repair genes and indicated that a successful DSB repair requires both DSB repair mechanisms and non-DSB repair systems. One of our recent studies found that suppressed expression of non-DSB repair genes, such as XPA, RPA and MLH1, influenced the yield of IR- induced micronuclei formation and/or chromosome aberrations, suggesting that these genes are highly involved in DSB repair and DSB-related cell cycle arrest, which reveals new roles for these gene products in the DNA repair network.
    [Show full text]
  • Architecture of the Human XPC DNA Repair and Stem Cell Coactivator Complex
    Architecture of the human XPC DNA repair and stem cell coactivator complex Elisa T. Zhanga,b,c, Yuan Hed,1, Patricia Groba,b, Yick W. Fonga,b,2, Eva Nogalesa,b,d, and Robert Tjiana,b,c,e,3 aDepartment of Molecular and Cell Biology, University of California, Berkeley, CA 94720; bHoward Hughes Medical Institute, Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720; cLi Ka Shing Center for Biomedical and Health Sciences, CIRM Center of Excellence, University of California Berkeley, CA 94720; dLife Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94710; and eHoward Hughes Medical Institute, Chevy Chase, MD 20815-6789 Contributed by Robert Tjian, October 16, 2015 (sent for review August 20, 2015; reviewed by Montserrat Samso and Ning Zheng) The Xeroderma pigmentosum complementation group C (XPC) involved in base excision repair (BER). BER is responsible for complex is a versatile factor involved in both nucleotide excision removing primarily non-helix-distorting lesions from the ge- repair and transcriptional coactivation as a critical component of nome (2). In BER, the XPC complex helps repair oxidative the NANOG, OCT4, and SOX2 pluripotency gene regulatory net- damage by stimulating the activities of DNA glycosylases such work. Here we present the structure of the human holo-XPC com- as OGG1 and TDG (3) to target lesions including 8-oxoguanine, plex determined by single-particle electron microscopy to reveal a independently of other downstream GG-NER factors (17). flexible, ear-shaped structure that undergoes localized loss of order More recently, the XPC complex has also been found to upon DNA binding.
    [Show full text]
  • Evidence for Two Independent Pathways of Biologically Effective Excision Repair from Its Rate and Extent in Cells Cultured from Sun-Sensitive Humans1
    [CANCER RESEARCH 47, 3725-3728, July 15, 1987] Evidence for Two Independent Pathways of Biologically Effective Excision Repair from Its Rate and Extent in Cells Cultured from Sun-sensitive Humans1 Rex M. Tyrrell and FrançoiseAmaudruz Swiss Institute for Cancer Research, CH-I066 Epalinges/Lausanne, Switzerland ABSTRACT a polymerase is the major polymerase involved in excision repair in both dividing and nondividing human fibroblasts so Repair-proficient human cells can be sensitized to exposure to UV that aphidicolin is the most specific blocker of eukaryotic radiation at 254 nm by postirradiation incubation in the presence of the eukaryotic a polymerase inhibitor, aphidicolin. The degree of sensitiza- excision repair currently available. In the present study, we have tion has been examined in cells cultured from humans suffering from exploited this fact in order to investigate the extent and rate of various types of sun-sensitive syndromes. Xeroderma pigmentosum (XP) BEER that occurs in various UV-sensitive human cell lines. variant and Bloom's cell lines (both excision proficient) were strongly- sensitized by aphidicolin. An excision repair proficient Cockayne's cell MATERIALS AND METHODS line and a deficient XPD line were both sensitized to a level similar to the sensitivity of excision deficient XPA cells. In contrast, three XPC Cell Strains and Culture. All primary human skin fibroblast strains cell lines which show intermediate UV-induced repair replication and were originally obtained from the Medical Research Council Cell UV sensitivity were sensitized little (in one case) or not at all (in two Mutation Unit (Sussex, England) except for XP12BE and GM 677 cases) to UV by postirradiation inhibition of the or polymerase.
    [Show full text]
  • Can Synthetic Lethality Approach Be Used with DNA Repair Genes for Primary and Secondary MDS?
    Medical Oncology (2019) 36:99 https://doi.org/10.1007/s12032-019-1324-7 ORIGINAL PAPER Can synthetic lethality approach be used with DNA repair genes for primary and secondary MDS? Howard Lopes Ribeiro Junior1,2 · Roberta Taiane Germano de Oliveira1,2 · Daniela de Paula Borges1,2 · Marília Braga Costa1,2 · Izabelle Rocha Farias1,2 · Antônio Wesley Araújo dos Santos1,2 · Silvia Maria Meira Magalhães1,2 · Ronald Feitosa Pinheiro1,2,3 Received: 5 August 2019 / Accepted: 15 October 2019 / Published online: 30 October 2019 © Springer Science+Business Media, LLC, part of Springer Nature 2019 Abstract Cancer-specifc defects in DNA repair pathways create the opportunity to employ synthetic lethality approach. Recently, GEMA (gene expression and mutation analysis) approach detected insufcient expression of BRCA or NHEJ (non-homol- ogous end joining) to predict PARP inhibitors response. We evaluated a possible role of DNA repair pathways using gene expression of single-strand break (XPA, XPC, XPG/ERCC5, CSA/ERCC8, and CSB/ERCC6) and double-strand break (ATM, BRCA1, BRCA2, RAD51, XRCC5, XRCC6, LIG4) in 92 patients with myelodysplastic syndrome (73 de novo, 9 therapy- related (t-MDS). Therapy-related MDS (t-MDS) demonstrated a signifcant downregulation of axis BRCA1-BRCA2-RAD51 comparing to normal controls (p = 0.048, p = 0.001, p = 0.001). XRCC6 showed signifcantly low expression in de novo MDS comparing to controls (p = 0.039) and for patients who presented chromosomal abnormalities (p = 0.047). Downregula- tion of LIG4 was consistently associated with poor prognostic markers in de novo MDS (hemoglobin < 8 g/dL (p = 0.040), neutrophils < 800/mm3 (p < 0.001), patients with excess of blasts (p = 0.001), very high (p = 0.002)/high IPSS-R (p = 0.043) and AML transformation (p < 0.001).
    [Show full text]