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Morren MA, Legius E, Giuliano F, Hadj-Rabia S, Hohl D, Bodemer C. Challenges in Treating Genodermatoses: New Therapies at the Horizon. Front Pharmacol 2022; 12:746664. [PMID: 35069188 PMCID: PMC8766835 DOI: 10.3389/fphar.2021.746664] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2021] [Accepted: 11/29/2021] [Indexed: 01/28/2023] Open
Abstract
Genodermatoses are rare inherited skin diseases that frequently affect other organs. They often have marked effects on wellbeing and may cause early death. Progress in molecular genetics and translational research has unravelled many underlying pathological mechanisms, and in several disorders with high unmet need, has opened the way for the introduction of innovative treatments. One approach is to intervene where cell-signaling pathways are dysregulated, in the case of overactive pathways by the use of selective inhibitors, or when the activity of an essential factor is decreased by augmenting a molecular component to correct disequilibrium in the pathway. Where inflammatory reactions have been induced by a genetically altered protein, another possible approach is to suppress the inflammation directly. Depending on the nature of the genodermatosis, the implicated protein or even on the particular mutation, to correct the consequences or the genetic defect, may require a highly personalised stratagem. Repurposed drugs, can be used to bring about a "read through" strategy especially where the genetic defect induces premature termination codons. Sometimes the defective protein can be replaced by a normal functioning one. Cell therapies with allogeneic normal keratinocytes or fibroblasts may restore the integrity of diseased skin and allogeneic bone marrow or mesenchymal cells may additionally rescue other affected organs. Genetic engineering is expanding rapidly. The insertion of a normal functioning gene into cells of the recipient is since long explored. More recently, genome editing, allows reframing, insertion or deletion of exons or disruption of aberrantly functioning genes. There are now several examples where these stratagems are being explored in the (pre)clinical phase of therapeutic trial programmes. Another stratagem, designed to reduce the severity of a given disease involves the use of RNAi to attenuate expression of a harmful protein by decreasing abundance of the cognate transcript. Most of these strategies are short-lasting and will thus require intermittent life-long administration. In contrast, insertion of healthy copies of the relevant gene or editing the disease locus in the genome to correct harmful mutations in stem cells is more likely to induce a permanent cure. Here we discuss the potential advantages and drawbacks of applying these technologies in patients with these genetic conditions. Given the severity of many genodermatoses, prevention of transmission to future generations remains an important goal including offering reproductive choices, such as preimplantation genetic testing, which can allow selection of an unaffected embryo for transfer to the uterus.
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Affiliation(s)
- Marie-Anne Morren
- Pediatric Dermatology Unit, Departments of Dermatology and Venereology and Pediatrics, University Hospital Lausanne, University of Lausanne, Lausanne, Switzerland
| | - Eric Legius
- Department for Human Genetics, University Hospitals Leuven, KU Leuven, ERN Genturis and ERN Skin, Leuven, Belgium
| | - Fabienne Giuliano
- Department of Medical Genetics, University Hospital Lausanne, Lausanne, Switzerland
| | - Smail Hadj-Rabia
- Department of Pediatric Dermatology and Dermatology, National Reference Centre for Genodermatosis and Rare Diseases of the Skin (MAGEC), Hôpital Necker-Enfants Malades, and Assistance Publique-Hôpitaux de Paris, Université Paris Descartes, ERN Skin, Paris, France
| | - Daniel Hohl
- Department of Dermatology and Venereology, University Hospital Lausanne, University of Lausanne, Lausanne, Switzerland
| | - Christine Bodemer
- Department of Pediatric Dermatology and Dermatology, National Reference Centre for Genodermatosis and Rare Diseases of the Skin (MAGEC), Hôpital Necker-Enfants Malades, and Assistance Publique-Hôpitaux de Paris, Université Paris Descartes, ERN Skin, Paris, France
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2
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Gupta R, Ambasta RK, Kumar P. Multifaced role of protein deacetylase sirtuins in neurodegenerative disease. Neurosci Biobehav Rev 2021; 132:976-997. [PMID: 34742724 DOI: 10.1016/j.neubiorev.2021.10.047] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Revised: 10/28/2021] [Accepted: 10/28/2021] [Indexed: 01/07/2023]
Abstract
Sirtuins, a class III histone/protein deacetylase, is a central regulator of metabolic function and cellular stress response. This plays a pivotal role in the pathogenesis and progression of diseases such as cancer, neurodegeneration, metabolic syndromes, and cardiovascular disease. Sirtuins regulate biological and cellular processes, for instance, mitochondrial biogenesis, lipid and fatty acid oxidation, oxidative stress, gene transcriptional activity, apoptosis, inflammatory response, DNA repair mechanism, and autophagic cell degradation, which are known components for the progression of the neurodegenerative diseases (NDDs). Emerging evidence suggests that sirtuins are the useful molecular targets against NDDs like, Alzheimer's Disease (AD), Parkinson's Disease (PD), Huntington's Disease (HD), and Amyotrophic Lateral Sclerosis (ALS). However, the exact mechanism of neuroprotection mediated through sirtuins remains unsettled. The manipulation of sirtuins activity with its modulators, calorie restriction (CR), and micro RNAs (miR) is a novel therapeutic approach for the treatment of NDDs. Herein, we reviewed the current putative therapeutic role of sirtuins in regulating synaptic plasticity and cognitive functions, which are mediated through the different molecular phenomenon to prevent neurodegeneration. We also explained the implications of sirtuin modulators, and miR based therapies for the treatment of life-threatening NDDs.
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Affiliation(s)
- Rohan Gupta
- Molecular Neuroscience and Functional Genomics Laboratory, Department of Biotechnology, Delhi Technological University (Formerly DCE), Delhi 110042, India
| | - Rashmi K Ambasta
- Molecular Neuroscience and Functional Genomics Laboratory, Department of Biotechnology, Delhi Technological University (Formerly DCE), Delhi 110042, India
| | - Pravir Kumar
- Molecular Neuroscience and Functional Genomics Laboratory, Department of Biotechnology, Delhi Technological University (Formerly DCE), Delhi 110042, India.
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3
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Friedman J, Bird LM, Haas R, Robbins SL, Nahas SA, Dimmock DP, Yousefzadeh MJ, Witt MA, Niedernhofer LJ, Chowdhury S. Ending a diagnostic odyssey: Moving from exome to genome to identify cockayne syndrome. Mol Genet Genomic Med 2021; 9:e1623. [PMID: 34076366 PMCID: PMC8372079 DOI: 10.1002/mgg3.1623] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 01/20/2021] [Accepted: 01/29/2021] [Indexed: 01/04/2023] Open
Abstract
Background Cockayne syndrome (CS) is a rare autosomal recessive disorder characterized by growth failure and multisystemic degeneration. Excision repair cross‐complementation group 6 (ERCC6 OMIM: *609413) is the gene most frequently mutated in CS. Methods A child with pre and postnatal growth failure and progressive neurologic deterioration with multisystem involvement, and with nondiagnostic whole‐exome sequencing, was screened for causal variants with whole‐genome sequencing (WGS). Results WGS identified biallelic ERCC6 variants, including a previously unreported intronic variant. Pathogenicity of these variants was established by demonstrating reduced levels of ERCC6 mRNA and protein expression, normal unscheduled DNA synthesis, and impaired recovery of RNA synthesis in patient fibroblasts following UV‐irradiation. Conclusion The study confirms the pathogenicity of a previously undescribed upstream intronic variant, highlighting the power of genome sequencing to identify noncoding variants. In addition, this report provides evidence for the utility of a combination approach of genome sequencing plus functional studies to provide diagnosis in a child for whom a lengthy diagnostic odyssey, including exome sequencing, was previously unrevealing.
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Affiliation(s)
- Jennifer Friedman
- Department of NeurosciencesUniversity of California San DiegoSan DiegoCAUSA
- Department of PediatricsUniversity of California San DiegoSan DiegoCAUSA
- Division of Neurology Rady Children’s HospitalSan DiegoCAUSA
- Rady Children’s Institute for Genomic MedicineSan DiegoCAUSA
| | - Lynne M. Bird
- Department of PediatricsUniversity of California San DiegoSan DiegoCAUSA
- Division of Genetics/DysmorphologyRady Children’s Hospital San DiegoSan DiegoCAUSA
| | - Richard Haas
- Department of NeurosciencesUniversity of California San DiegoSan DiegoCAUSA
- Department of PediatricsUniversity of California San DiegoSan DiegoCAUSA
- Division of Neurology Rady Children’s HospitalSan DiegoCAUSA
| | - Shira L. Robbins
- Viterbi Family Department of Ophthalmology at the Shiley Eye InstituteUniversity of California San DiegoLa JollaCAUSA
| | | | | | - Matthew J. Yousefzadeh
- Institute on the Biology of Aging and MetabolismDepartment of Biochemistry, Molecular Biology and BiophysicsUniversity of MinnesotaMinneapolisMNUSA
| | - Mariah A. Witt
- Institute on the Biology of Aging and MetabolismDepartment of Biochemistry, Molecular Biology and BiophysicsUniversity of MinnesotaMinneapolisMNUSA
| | - Laura J. Niedernhofer
- Institute on the Biology of Aging and MetabolismDepartment of Biochemistry, Molecular Biology and BiophysicsUniversity of MinnesotaMinneapolisMNUSA
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Sirtuin 1 and Skin: Implications in Intrinsic and Extrinsic Aging-A Systematic Review. Cells 2021; 10:cells10040813. [PMID: 33917352 PMCID: PMC8067363 DOI: 10.3390/cells10040813] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2021] [Revised: 03/28/2021] [Accepted: 04/02/2021] [Indexed: 02/06/2023] Open
Abstract
Skin, as the outermost organ of the body, is constantly exposed to both intrinsic and extrinsic causative factors of aging. Intrinsic aging is related to compromised cellular proliferative capacity, and may be accelerated by harmful environmental influences with the greatest significance of ultraviolet radiation exposure, contributing not only to premature aging, but also to skin carcinogenesis. The overall skin cancer burden and steadily increasing global antiaging market provide an incentive for searching novel targets to improve skin resistance against external injury. Sirtuin 1, initially linked to extension of yeast and rodent lifespan, plays a key role in epigenetic modification of proteins, histones, and chromatin by which regulates the expression of genes implicated in the oxidative stress response and apoptosis. The spectrum of cellular pathways regulated by sirtuin 1 suggests its beneficial impact on skin aging. However, the data on its role in carcinogenesis remains controversial. The aim of this review was to discuss the relevance of sirtuin 1 in skin aging, in the context of intrinsic factors, related to genetic premature aging syndromes, as well as extrinsic modifiable ones, with the assessment of its future application. PubMed were searched from inception to 4 January 2021 for relevant papers with further search carried out on ClinicalTrials.gov. The systematic review included 46 eligible original articles. The evidence from numerous studies proves sirtuin 1 significance in both chronological and premature aging as well as its dual role in cancer development. Several botanical compounds hold the potential to improve skin aging symptoms.
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Zurita M, Murillo-Maldonado JM. Drosophila as a Model Organism to Understand the Effects during Development of TFIIH-Related Human Diseases. Int J Mol Sci 2020; 21:ijms21020630. [PMID: 31963603 PMCID: PMC7013941 DOI: 10.3390/ijms21020630] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Revised: 12/02/2019] [Accepted: 12/02/2019] [Indexed: 12/20/2022] Open
Abstract
Human mutations in the transcription and nucleotide excision repair (NER) factor TFIIH are linked with three human syndromes: xeroderma pigmentosum (XP), trichothiodystrophy (TTD) and Cockayne syndrome (CS). In particular, different mutations in the XPB, XPD and p8 subunits of TFIIH may cause one or a combination of these syndromes, and some of these mutations are also related to cancer. The participation of TFIIH in NER and transcription makes it difficult to interpret the different manifestations observed in patients, particularly since some of these phenotypes may be related to problems during development. TFIIH is present in all eukaryotic cells, and its functions in transcription and DNA repair are conserved. Therefore, Drosophila has been a useful model organism for the interpretation of different phenotypes during development as well as the understanding of the dynamics of this complex. Interestingly, phenotypes similar to those observed in humans caused by mutations in the TFIIH subunits are present in mutant flies, allowing the study of TFIIH in different developmental processes. Furthermore, studies performed in Drosophila of mutations in different subunits of TFIIH that have not been linked to any human diseases, probably because they are more deleterious, have revealed its roles in differentiation and cell death. In this review, different achievements made through studies in the fly to understand the functions of TFIIH during development and its relationship with human diseases are analysed and discussed.
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6
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Rescue of premature aging defects in Cockayne syndrome stem cells by CRISPR/Cas9-mediated gene correction. Protein Cell 2019; 11:1-22. [PMID: 31037510 PMCID: PMC6949206 DOI: 10.1007/s13238-019-0623-2] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Accepted: 03/12/2019] [Indexed: 01/07/2023] Open
Abstract
Cockayne syndrome (CS) is a rare autosomal recessive inherited disorder characterized by a variety of clinical features, including increased sensitivity to sunlight, progressive neurological abnormalities, and the appearance of premature aging. However, the pathogenesis of CS remains unclear due to the limitations of current disease models. Here, we generate integration-free induced pluripotent stem cells (iPSCs) from fibroblasts from a CS patient bearing mutations in CSB/ERCC6 gene and further derive isogenic gene-corrected CS-iPSCs (GC-iPSCs) using the CRISPR/Cas9 system. CS-associated phenotypic defects are recapitulated in CS-iPSC-derived mesenchymal stem cells (MSCs) and neural stem cells (NSCs), both of which display increased susceptibility to DNA damage stress. Premature aging defects in CS-MSCs are rescued by the targeted correction of mutant ERCC6. We next map the transcriptomic landscapes in CS-iPSCs and GC-iPSCs and their somatic stem cell derivatives (MSCs and NSCs) in the absence or presence of ultraviolet (UV) and replicative stresses, revealing that defects in DNA repair account for CS pathologies. Moreover, we generate autologous GC-MSCs free of pathogenic mutation under a cGMP (Current Good Manufacturing Practice)-compliant condition, which hold potential for use as improved biomaterials for future stem cell replacement therapy for CS. Collectively, our models demonstrate novel disease features and molecular mechanisms and lay a foundation for the development of novel therapeutic strategies to treat CS.
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7
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Ferri D, Orioli D, Botta E. Heterogeneity and overlaps in nucleotide excision repair disorders. Clin Genet 2019; 97:12-24. [PMID: 30919937 DOI: 10.1111/cge.13545] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Revised: 02/27/2019] [Accepted: 03/26/2019] [Indexed: 12/22/2022]
Abstract
Nucleotide excision repair (NER) is an essential DNA repair pathway devoted to the removal of bulky lesions such as photoproducts induced by the ultraviolet (UV) component of solar radiation. Deficiencies in NER typically result in a group of heterogeneous distinct disorders ranging from the mild UV sensitive syndrome to the cancer-prone xeroderma pigmentosum and the neurodevelopmental/progeroid conditions trichothiodystrophy, Cockayne syndrome and cerebro-oculo-facio-skeletal-syndrome. A complicated genetic scenario underlines these disorders with the same gene linked to different clinical entities as well as different genes associated with the same disease. Overlap syndromes with combined hallmark features of different NER disorders can occur and sporadic presentations showing extra features of the hematological disorder Fanconi Anemia or neurological manifestations mimicking Hungtinton disease-like syndromes have been described. Here, we discuss the multiple functions of the five major pleiotropic NER genes (ERCC3/XPB, ERCC2/XPD, ERCC5/XPG, ERCC1 and ERCC4/XPF) and their relevance in phenotypic complexity. We provide an update of mutational spectra and examine genotype-phenotype relationships. Finally, the molecular defects that could explain the puzzling overlap syndromes are discussed.
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Affiliation(s)
- Debora Ferri
- Istituto di Genetica Molecolare (IGM), Consiglio Nazionale delle Ricerche, Pavia, Italy
| | - Donata Orioli
- Istituto di Genetica Molecolare (IGM), Consiglio Nazionale delle Ricerche, Pavia, Italy
| | - Elena Botta
- Istituto di Genetica Molecolare (IGM), Consiglio Nazionale delle Ricerche, Pavia, Italy
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8
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Weon J, Glass D. Novel therapeutic approaches to xeroderma pigmentosum. Br J Dermatol 2018; 181:249-255. [DOI: 10.1111/bjd.17253] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/19/2018] [Indexed: 12/26/2022]
Affiliation(s)
- J.L. Weon
- Department of Dermatology University of Texas Southwestern Medical Center Dallas TX 75390U.S.A
| | - D.A. Glass
- Department of Dermatology University of Texas Southwestern Medical Center Dallas TX 75390U.S.A
- McDermott Center for Human Growth and Development University of Texas Southwestern Medical Center Dallas TX 75390 U.S.A
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9
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Gregersen LH, Svejstrup JQ. The Cellular Response to Transcription-Blocking DNA Damage. Trends Biochem Sci 2018; 43:327-341. [PMID: 29699641 PMCID: PMC5929563 DOI: 10.1016/j.tibs.2018.02.010] [Citation(s) in RCA: 91] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Revised: 02/16/2018] [Accepted: 02/19/2018] [Indexed: 12/27/2022]
Abstract
In response to transcription-blocking DNA lesions such as those generated by UV irradiation, cells activate a multipronged DNA damage response. This response encompasses repair of the lesions that stall RNA polymerase (RNAP) but also a poorly understood, genome-wide shutdown of transcription, even of genes that are not damaged. Over the past few years, a number of new results have shed light on this intriguing DNA damage response at the structural, biochemical, cell biological, and systems biology level. In this review we summarize the most important findings.
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Affiliation(s)
- Lea H Gregersen
- Mechanisms of Transcription Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Jesper Q Svejstrup
- Mechanisms of Transcription Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK.
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10
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Rimel JK, Taatjes DJ. The essential and multifunctional TFIIH complex. Protein Sci 2018; 27:1018-1037. [PMID: 29664212 PMCID: PMC5980561 DOI: 10.1002/pro.3424] [Citation(s) in RCA: 82] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2018] [Revised: 04/04/2018] [Accepted: 04/05/2018] [Indexed: 12/19/2022]
Abstract
TFIIH is a 10‐subunit complex that regulates RNA polymerase II (pol II) transcription but also serves other important biological roles. Although much remains unknown about TFIIH function in eukaryotic cells, much progress has been made even in just the past few years, due in part to technological advances (e.g. cryoEM and single molecule methods) and the development of chemical inhibitors of TFIIH enzymes. This review focuses on the major cellular roles for TFIIH, with an emphasis on TFIIH function as a regulator of pol II transcription. We describe the structure of TFIIH and its roles in pol II initiation, promoter‐proximal pausing, elongation, and termination. We also discuss cellular roles for TFIIH beyond transcription (e.g. DNA repair, cell cycle regulation) and summarize small molecule inhibitors of TFIIH and diseases associated with defects in TFIIH structure and function.
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Affiliation(s)
- Jenna K Rimel
- Department of Chemistry & Biochemistry, University of Colorado, Boulder, Colorado, 80303
| | - Dylan J Taatjes
- Department of Chemistry & Biochemistry, University of Colorado, Boulder, Colorado, 80303
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11
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Carrero D, Soria-Valles C, López-Otín C. Hallmarks of progeroid syndromes: lessons from mice and reprogrammed cells. Dis Model Mech 2017; 9:719-35. [PMID: 27482812 PMCID: PMC4958309 DOI: 10.1242/dmm.024711] [Citation(s) in RCA: 91] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Ageing is a process that inevitably affects most living organisms and involves the accumulation of macromolecular damage, genomic instability and loss of heterochromatin. Together, these alterations lead to a decline in stem cell function and to a reduced capability to regenerate tissue. In recent years, several genetic pathways and biochemical mechanisms that contribute to physiological ageing have been described, but further research is needed to better characterize this complex biological process. Because premature ageing (progeroid) syndromes, including progeria, mimic many of the characteristics of human ageing, research into these conditions has proven to be very useful not only to identify the underlying causal mechanisms and identify treatments for these pathologies, but also for the study of physiological ageing. In this Review, we summarize the main cellular and animal models used in progeria research, with an emphasis on patient-derived induced pluripotent stem cell models, and define a series of molecular and cellular hallmarks that characterize progeroid syndromes and parallel physiological ageing. Finally, we describe the therapeutic strategies being investigated for the treatment of progeroid syndromes, and their main limitations. Summary: This Review defines the molecular and cellular hallmarks of progeroid syndromes according to the main cellular and animal models, and discusses the therapeutic strategies developed to date.
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Affiliation(s)
- Dido Carrero
- Departamento de Bioquímica y Biología Molecular, Facultad de Medicina, Instituto Universitario de Oncología (IUOPA), Universidad de Oviedo, Oviedo 33006, Spain
| | - Clara Soria-Valles
- Departamento de Bioquímica y Biología Molecular, Facultad de Medicina, Instituto Universitario de Oncología (IUOPA), Universidad de Oviedo, Oviedo 33006, Spain
| | - Carlos López-Otín
- Departamento de Bioquímica y Biología Molecular, Facultad de Medicina, Instituto Universitario de Oncología (IUOPA), Universidad de Oviedo, Oviedo 33006, Spain
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12
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Mori T, Yousefzadeh MJ, Faridounnia M, Chong JX, Hisama FM, Hudgins L, Mercado G, Wade EA, Barghouthy AS, Lee L, Martin GM, Nickerson DA, Bamshad MJ, Niedernhofer LJ, Oshima J. ERCC4 variants identified in a cohort of patients with segmental progeroid syndromes. Hum Mutat 2017; 39:255-265. [PMID: 29105242 DOI: 10.1002/humu.23367] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Revised: 09/26/2017] [Accepted: 10/29/2017] [Indexed: 12/30/2022]
Abstract
Pathogenic variants in genes, which encode DNA repair and damage response proteins, result in a number of genomic instability syndromes with features of accelerated aging. ERCC4 (XPF) encodes a protein that forms a complex with ERCC1 and is required for the 5' incision during nucleotide excision repair. ERCC4 is also FANCQ, illustrating a critical role in interstrand crosslink repair. Pathogenic variants in this gene cause xeroderma pigmentosum, XFE progeroid syndrome, Cockayne syndrome (CS), and Fanconi anemia. We performed massive parallel sequencing for 42 unsolved cases submitted to the International Registry of Werner Syndrome. Two cases, each carrying two novel heterozygous ERCC4 variants, were identified. The first case was a compound heterozygote for: c.2395C > T (p.Arg799Trp) and c.388+1164_792+795del (p.Gly130Aspfs*18). Further molecular and cellular studies indicated that the ERCC4 variants in this patient are responsible for a phenotype consistent with a variant of CS. The second case was heterozygous for two variants in cis: c.[1488A > T; c.2579C > A] (p.[Gln496His; Ala860Asp]). While the second case also had several phenotypic features of accelerated aging, we were unable to provide biological evidence supporting the pathogenic roles of the associated ERCC4 variants. Precise genetic causes and disease mechanism of the second case remains to be determined.
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Affiliation(s)
- Takayasu Mori
- Division of Genetic Medicine, Department of Pediatrics, University of Washington, Seattle, Washington
| | - Matthew J Yousefzadeh
- Department of Molecular Medicine, Center on Aging, The Scripps Research Institute, Jupiter, Florida
| | - Maryam Faridounnia
- Department of Molecular Medicine, Center on Aging, The Scripps Research Institute, Jupiter, Florida
| | - Jessica X Chong
- Division of Genetic Medicine, Department of Pediatrics, University of Washington, Seattle, Washington
| | - Fuki M Hisama
- Division of Medical Genetics, Department of Medicine, University of Washington, Seattle, Washington
| | - Louanne Hudgins
- Division of Medical Genetics, Stanford University School of Medicine, Stanford, California
| | | | - Erin A Wade
- Department of Molecular Medicine, Center on Aging, The Scripps Research Institute, Jupiter, Florida
| | - Amira S Barghouthy
- Department of Molecular Medicine, Center on Aging, The Scripps Research Institute, Jupiter, Florida
| | - Lin Lee
- Department of Pathology, University of Washington, Seattle, Washington
| | - George M Martin
- Department of Pathology, University of Washington, Seattle, Washington
| | - Deborah A Nickerson
- Department of Genome Sciences, University of Washington, Seattle, Washington
| | - Michael J Bamshad
- Division of Genetic Medicine, Department of Pediatrics, University of Washington, Seattle, Washington.,Department of Genome Sciences, University of Washington, Seattle, Washington.,Division of Genetic Medicine, Seattle Children's Hospital, Seattle, Washington
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- Division of Genetic Medicine, Department of Pediatrics, University of Washington, Seattle, Washington
| | - Laura J Niedernhofer
- Department of Molecular Medicine, Center on Aging, The Scripps Research Institute, Jupiter, Florida
| | - Junko Oshima
- Department of Pathology, University of Washington, Seattle, Washington.,Department of Clinical Cell Biology and Medicine, Graduate School of Medicine, Chiba University, Chiba, Japan
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Wu X, Cao N, Fenech M, Wang X. Role of Sirtuins in Maintenance of Genomic Stability: Relevance to Cancer and Healthy Aging. DNA Cell Biol 2016; 35:542-575. [DOI: 10.1089/dna.2016.3280] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Affiliation(s)
- Xiayu Wu
- School of Life Sciences, The Engineering Research Center of Sustainable Development and Utilization of Biomass Energy, Ministry of Education, Yunnan Normal University, Kunming, Yunnan, China
| | - Neng Cao
- School of Life Sciences, The Engineering Research Center of Sustainable Development and Utilization of Biomass Energy, Ministry of Education, Yunnan Normal University, Kunming, Yunnan, China
| | - Michael Fenech
- Genome Health and Personalized Nutrition, Commonwealth Scientific and Industrial Research Organization Food and Nutrition, Adelaide, South Australia, Australia
| | - Xu Wang
- School of Life Sciences, The Engineering Research Center of Sustainable Development and Utilization of Biomass Energy, Ministry of Education, Yunnan Normal University, Kunming, Yunnan, China
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14
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Moriel-Carretero M, Herrera-Moyano E, Aguilera A. A unified model for the molecular basis of Xeroderma pigmentosum-Cockayne Syndrome. Rare Dis 2015; 3:e1079362. [PMID: 26460500 PMCID: PMC4588225 DOI: 10.1080/21675511.2015.1079362] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2015] [Revised: 06/02/2015] [Accepted: 07/28/2015] [Indexed: 11/26/2022] Open
Abstract
Nucleotide Excision Repair (NER) is a pathway that removes lesions distorting the DNA helix. The molecular basis of the rare diseases Xeroderma pigmentosum (XP) and Cockayne Syndrome (CS) are explained based on the defects happening in 2 NER branches: Global-Genome Repair and Transcription-Coupled Repair, respectively. Nevertheless, both afflictions sporadically occur together, giving rise to XP/CS; however, the molecular basis of XP/CS is not understood very well. Many efforts have been made to clarify why mutations in only 4 NER genes, namely XPB, XPD, XPF and XPG, are the basis of this disease. Effort has also been made to unravel why mutations within these genes lead to XP, XP/CS, or other pathologies. We have recently contributed to the disclosure of this puzzle by characterizing Rad3/XPD mutations in Saccharomyces cerevisiae and human cells. Based on our, and others', observations, we propose a model compatible with all XP/CS cases and the current bibliography.
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Affiliation(s)
- María Moriel-Carretero
- Centro Andaluz de Biología Molecular y Medicina Regenerativa CABIMER; Universidad de Sevilla ; Seville, Spain ; Institute of Human Genetics; CNRS-UPR1142 ; Montpellier, France
| | - Emilia Herrera-Moyano
- Centro Andaluz de Biología Molecular y Medicina Regenerativa CABIMER; Universidad de Sevilla ; Seville, Spain
| | - Andrés Aguilera
- Centro Andaluz de Biología Molecular y Medicina Regenerativa CABIMER; Universidad de Sevilla ; Seville, Spain
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Regulation of Transcription Elongation by the XPG-TFIIH Complex Is Implicated in Cockayne Syndrome. Mol Cell Biol 2015; 35:3178-88. [PMID: 26149386 DOI: 10.1128/mcb.01401-14] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2014] [Accepted: 06/23/2015] [Indexed: 11/20/2022] Open
Abstract
XPG is a causative gene underlying the photosensitive disorder xeroderma pigmentosum group G (XP-G) and is involved in nucleotide excision repair. Here, we show that XPG knockdown represses epidermal growth factor (EGF)-induced FOS transcription at the level of transcription elongation with little effect on EGF signal transduction. XPG interacted with transcription elongation factors in concert with TFIIH, suggesting that the XPG-TFIIH complex serves as a transcription elongation factor. The XPG-TFIIH complex was recruited to promoter and coding regions of both EGF-induced (FOS) and housekeeping (EEF1A1) genes. Further, EGF-induced recruitment of RNA polymerase II and TFIIH to FOS was reduced by XPG knockdown. Importantly, EGF-induced FOS transcription was markedly lower in XP-G/Cockayne syndrome (CS) cells expressing truncated XPG than in control cells expressing wild-type (WT) XPG, with less significant decreases in XP-G cells with XPG nuclease domain mutations. In corroboration of this finding, both WT XPG and a missense XPG mutant from an XP-G patient were recruited to FOS upon EGF stimulation, but an XPG mutant mimicking a C-terminal truncation from an XP-G/CS patient was not. These results suggest that the XPG-TFIIH complex is involved in transcription elongation and that defects in this association may partly account for Cockayne syndrome in XP-G/CS patients.
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The rem mutations in the ATP-binding groove of the Rad3/XPD helicase lead to Xeroderma pigmentosum-Cockayne syndrome-like phenotypes. PLoS Genet 2014; 10:e1004859. [PMID: 25500814 PMCID: PMC4263401 DOI: 10.1371/journal.pgen.1004859] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2014] [Accepted: 10/28/2014] [Indexed: 11/19/2022] Open
Abstract
The eukaryotic TFIIH complex is involved in Nucleotide Excision Repair and transcription initiation. We analyzed three yeast mutations of the Rad3/XPD helicase of TFIIH known as rem (recombination and mutation phenotypes). We found that, in these mutants, incomplete NER reactions lead to replication fork breaking and the subsequent engagement of the homologous recombination machinery to restore them. Nevertheless, the penetrance varies among mutants, giving rise to a phenotype gradient. Interestingly, the mutations analyzed reside at the ATP-binding groove of Rad3 and in vivo experiments reveal a gain of DNA affinity upon damage of the mutant Rad3 proteins. Since mutations at the ATP-binding groove of XPD in humans are present in the Xeroderma pigmentosum-Cockayne Syndrome (XP-CS), we recreated rem mutations in human cells, and found that these are XP-CS-like. We propose that the balance between the loss of helicase activity and the gain of DNA affinity controls the capacity of TFIIH to open DNA during NER, and its persistence at both DNA lesions and promoters. This conditions NER efficiency and transcription resumption after damage, which in human cells would explain the XP-CS phenotype, opening new perspectives to understand the molecular basis of the role of XPD in human disease. TFIIH is a protein complex that functions in the repair of bulky adducts distorting the DNA via the pathway of Nucleotide Excision Repair, and in transcription initiation and transactivation, the latter being a specific transcription activation process occurring in response to hormones. We have taken advantage of the powerful genetics and molecular biology of the model organism Saccharomyces cerevisiae to characterize the impact on cell fitness of a particular kind of mutations of one of the two helicases of the TFIIH complex, Rad3, called rem mutations for their increased levels of recombination and mutation. We have realized that these mutations affect a particular site of the protein, its ATP-binding groove, and modify the dynamics of TFIIH, leading to unfinished repair reactions and DNA break accumulation. Finally, we recreated these mutations in the human homolog XPD protein and found that their phenotypes recapitulated those of human mutations leading to a combination of the two hereditary diseases Xeroderma pigmentosum and Cockayne syndrome (XP-D/CS), whose molecular basis remains elusive. As these mutations also affect the ATP-binding groove of XPD, this study permits to propose a model to explain the molecular basis of XP-D/CS.
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Traboulsi H, Davoli S, Catez P, Egly JM, Compe E. Dynamic partnership between TFIIH, PGC-1α and SIRT1 is impaired in trichothiodystrophy. PLoS Genet 2014; 10:e1004732. [PMID: 25340339 PMCID: PMC4207666 DOI: 10.1371/journal.pgen.1004732] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2014] [Accepted: 09/04/2014] [Indexed: 12/05/2022] Open
Abstract
The expression of protein-coding genes requires the selective role of many transcription factors, whose coordinated actions remain poorly understood. To further grasp the molecular mechanisms that govern transcription, we focused our attention on the general transcription factor TFIIH, which gives rise, once mutated, to Trichothiodystrophy (TTD), a rare autosomal premature-ageing disease causing inter alia, metabolic dysfunctions. Since this syndrome could be connected to transcriptional defects, we investigated the ability of a TTD mouse model to cope with food deprivation, knowing that energy homeostasis during fasting involves an accurate regulation of the gluconeogenic genes in the liver. Abnormal amounts of gluconeogenic enzymes were thus observed in TTD hepatic parenchyma, which was related to the dysregulation of the corresponding genes. Strikingly, such gene expression defects resulted from the inability of PGC1-α to fulfill its role of coactivator. Indeed, extensive molecular analyses unveiled that wild-type TFIIH cooperated in an ATP-dependent manner with PGC1-α as well as with the deacetylase SIRT1, thereby contributing to the PGC1-α deacetylation by SIRT1. Such dynamic partnership was, however, impaired when TFIIH was mutated, having as a consequence the disruption of PGC1-α recruitment to the promoter of target genes. Therefore, besides a better understanding of the etiology of TFIIH-related disease, our results shed light on the synergistic relationship that exist between different types of transcription factors, which is necessary to properly regulate the expression of protein coding genes. In eukaryotes, the expression of genes encoding proteins requires the action of hundreds of factors, together with the RNA polymerase II. While these factors are timely and selectively required for the expression of a given gene, little is known about their partnership upon gene expression. Our results reveal a cooperation between different types of transcription factors, namely the general transcription factor TFIIH, the cofactor PGC-1α and the deacetylase SIRT1. Such partnership is however impaired when TFIIH is mutated, as observed in Trichothiodystrophy patients that develop premature ageing. These results thus shed light on the coordinated action of factors during transcription and allow us to better understand molecular deficiencies observed in many human diseases.
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Affiliation(s)
- Hussein Traboulsi
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, Strasbourg, France
| | - Serena Davoli
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, Strasbourg, France
| | - Philippe Catez
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, Strasbourg, France
| | - Jean-Marc Egly
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, Strasbourg, France
- * E-mail: (JME); (EC)
| | - Emmanuel Compe
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, Strasbourg, France
- * E-mail: (JME); (EC)
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18
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Gyenis Á, Umlauf D, Újfaludi Z, Boros I, Ye T, Tora L. UVB induces a genome-wide acting negative regulatory mechanism that operates at the level of transcription initiation in human cells. PLoS Genet 2014; 10:e1004483. [PMID: 25058334 PMCID: PMC4109906 DOI: 10.1371/journal.pgen.1004483] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2013] [Accepted: 05/19/2014] [Indexed: 11/19/2022] Open
Abstract
Faithful transcription of DNA is constantly threatened by different endogenous and environmental genotoxic effects. Transcription coupled repair (TCR) has been described to stop transcription and quickly remove DNA lesions from the transcribed strand of active genes, permitting rapid resumption of blocked transcription. This repair mechanism has been well characterized in the past using individual target genes. Moreover, numerous efforts investigated the fate of blocked RNA polymerase II (Pol II) during DNA repair mechanisms and suggested that stopped Pol II complexes can either backtrack, be removed and degraded or bypass the lesions to allow TCR. We investigated the effect of a non-lethal dose of UVB on global DNA-bound Pol II distribution in human cells. We found that the used UVB dose did not induce Pol II degradation however surprisingly at about 93% of the promoters of all expressed genes Pol II occupancy was seriously reduced 2-4 hours following UVB irradiation. The presence of Pol II at these cleared promoters was restored 5-6 hours after irradiation, indicating that the negative regulation is very dynamic. We also identified a small set of genes (including several p53 regulated genes), where the UVB-induced Pol II clearing did not operate. Interestingly, at promoters, where Pol II promoter clearance occurs, TFIIH, but not TBP, follows the behavior of Pol II, suggesting that at these genes upon UVB treatment TFIIH is sequestered for DNA repair by the TCR machinery. In agreement, in cells where the TCR factor, the Cockayne Syndrome B protein, was depleted UVB did not induce Pol II and TFIIH clearance at promoters. Thus, our study reveals a UVB induced negative regulatory mechanism that targets Pol II transcription initiation on the large majority of transcribed gene promoters, and a small subset of genes, where Pol II escapes this negative regulation.
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Affiliation(s)
- Ákos Gyenis
- Cellular signaling and nuclear dynamics program, Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France
- Centre National de la Recherche Scientifique, UMR7104, Illkirch, France
- Institut National de la Santé et de la Recherche Médicale, U964, Illkirch, France
- Université de Strasbourg, Illkirch, France
| | - David Umlauf
- Cellular signaling and nuclear dynamics program, Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France
- Centre National de la Recherche Scientifique, UMR7104, Illkirch, France
- Institut National de la Santé et de la Recherche Médicale, U964, Illkirch, France
- Université de Strasbourg, Illkirch, France
| | - Zsuzsanna Újfaludi
- University of Szeged, Faculty of Sciences and Informatics, Department of Biochemistry and Molecular Biology, Szeged, Hungary
| | - Imre Boros
- University of Szeged, Faculty of Sciences and Informatics, Department of Biochemistry and Molecular Biology, Szeged, Hungary
| | - Tao Ye
- Centre National de la Recherche Scientifique, UMR7104, Illkirch, France
- Institut National de la Santé et de la Recherche Médicale, U964, Illkirch, France
- Université de Strasbourg, Illkirch, France
- Microarrays and deep sequencing platform, Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France
| | - Làszlò Tora
- Cellular signaling and nuclear dynamics program, Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France
- Centre National de la Recherche Scientifique, UMR7104, Illkirch, France
- Institut National de la Santé et de la Recherche Médicale, U964, Illkirch, France
- Université de Strasbourg, Illkirch, France
- * E-mail:
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Blurring the line between the DNA damage response and transcription: the importance of chromatin dynamics. Exp Cell Res 2014; 329:148-53. [PMID: 25062983 PMCID: PMC5111725 DOI: 10.1016/j.yexcr.2014.07.017] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Accepted: 07/14/2014] [Indexed: 01/18/2023]
Abstract
DNA damage interferes with the progression of transcription machineries. A tight coordination of transcription with signaling and repair of DNA damage is thus critical for safeguarding genome function. This coordination involves modulations of chromatin organization. Here, we focus on the central role of chromatin dynamics, in conjunction with DNA Damage Response (DDR) factors, in controlling transcription inhibition and restart at sites of DNA damage in mammalian cells. Recent work has identified chromatin modifiers and histone chaperones as key regulators of transcriptional activity in damaged chromatin regions. Conversely, the transcriptional state of chromatin before DNA damage influences both DNA damage signaling and repair. We discuss the importance of chromatin plasticity in coordinating the interplay between the DDR and transcription, with major implications for cell fate maintenance.
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20
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Li Z, Zhu WG. Targeting histone deacetylases for cancer therapy: from molecular mechanisms to clinical implications. Int J Biol Sci 2014; 10:757-70. [PMID: 25013383 PMCID: PMC4081609 DOI: 10.7150/ijbs.9067] [Citation(s) in RCA: 118] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Accepted: 04/02/2014] [Indexed: 12/19/2022] Open
Abstract
Genetic abnormalities have been conventionally considered as hallmarks of cancer. However, studies over the past decades have demonstrated that epigenetic regulation also participates in the development of cancer. The fundamental patterns of epigenetic components, such as DNA methylation and histone modifications, are frequently altered in tumor cells. Acetylation is one of the best characterized modifications of histones, which is controlled by histone acetyltransferases (HATs) and histone deacetylases (HDACs). HDACs are a group of enzymes which catalyze the removal of the acetyl groups of both histones and non-histone proteins. HDACs are involved in modulating most key cellular processes, including transcriptional regulation, apoptosis, DNA damage repair, cell cycle control, autophagy, metabolism, senescence and chaperone function. Because HDACs have been found to function incorrectly in cancer, various HDAC inhibitors are being investigated to act as cancer chemotherapeutics. The primary purpose of this paper is to summarize recent studies of the links between HDACs and cancer, and further discuss the underlying mechanisms of anti-tumor activities of HDAC inhibitors and clinical implications.
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Affiliation(s)
- Zhiming Li
- 1. Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Beijing 100191, China. ; 2. Department of Biochemistry and Molecular Biology, Peking University Health Science Center, Beijing, 100191, China
| | - Wei-Guo Zhu
- 1. Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Beijing 100191, China. ; 2. Department of Biochemistry and Molecular Biology, Peking University Health Science Center, Beijing, 100191, China. ; 3. Peking-Tsinghua University Center for Life Sciences, Peking University, Beijing 100871, China
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Abstract
SIGNIFICANCE Production of proteins requires the synthesis, maturation, and export of mRNAs before their translation in the cytoplasm. Endogenous and exogenous sources of DNA damage pose a challenge to the co-ordinated regulation of gene expression, because the integrity of the DNA template can be compromised by DNA lesions. Cells recognize and respond to this DNA damage through a variety of DNA damage responses (DDRs). Failure to deal with DNA damage appropriately can lead to genomic instability and cancer. RECENT ADVANCES The p53 tumor suppressor plays a dominant role in DDR-dependent changes in gene expression, but this transcription factor is not solely responsible for all changes. Recent evidence indicates that RNA metabolism is integral to DDRs as well. In particular, post-transcriptional processes are emerging as important contributors to these complex responses. CRITICAL ISSUES Transcriptional, post-transcriptional, and translational regulation of gene expression is subject to changes in response to DNA damage. How these processes are intertwined in the unfolding of DDR is not fully understood. FUTURE DIRECTIONS Many complex regulatory responses combine to determine cell fate after DNA damage. Understanding how transcriptional, post-transcriptional, and translational processes interdigitate to create a web of regulatory interactions will be one of the key challenges to fully understand DDRs.
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Affiliation(s)
- Bruce C McKay
- Department of Biology, Institute of Biochemistry, Carleton University , Ottawa, Canada
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22
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Brooks PJ. Blinded by the UV light: how the focus on transcription-coupled NER has distracted from understanding the mechanisms of Cockayne syndrome neurologic disease. DNA Repair (Amst) 2013; 12:656-71. [PMID: 23683874 PMCID: PMC4240003 DOI: 10.1016/j.dnarep.2013.04.018] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Cockayne syndrome (CS) is a devastating neurodevelopmental disorder, with growth abnormalities, progeriod features, and sun sensitivity. CS is typically considered to be a DNA repair disorder, since cells from CS patients have a defect in transcription-coupled nucleotide excision repair (TC-NER). However, cells from UV-sensitive syndrome patients also lack TC-NER, but these patients do not suffer from the neurologic and other abnormalities that CS patients do. Also, the neurologic abnormalities that affect CS patients (CS neurologic disease) are qualitatively different from those seen in NER-deficient XP patients. Therefore, the TC-NER defect explains the sun sensitive phenotype common to both CS and UVsS, but cannot explain CS neurologic disease. However, as CS neurologic disease is of much greater clinical significance than the sun sensitivity, there is a pressing need to understand its molecular basis. While there is evidence for defective repair of oxidative DNA damage and mitochondrial abnormalities in CS cells, here I propose that the defects in transcription by both RNA polymerases I and II that have been documented in CS cells provide a better explanation for many of the severe growth and neurodevelopmental defects in CS patients than defective DNA repair. The implications of these ideas for interpreting results from mouse models of CS, and for the development of treatments and therapies for CS patients are discussed.
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Affiliation(s)
- P J Brooks
- Laboratory of Neurogenetics, National Institute on Alcohol Abuse and Alcoholism, NIH, 5625 Fishers Lane, 3S-32, Bethesda, MD 20892, USA.
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Regulatory interplay of Cockayne syndrome B ATPase and stress-response gene ATF3 following genotoxic stress. Proc Natl Acad Sci U S A 2013; 110:E2261-70. [PMID: 23733932 DOI: 10.1073/pnas.1220071110] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Cockayne syndrome type B ATPase (CSB) belongs to the SwItch/Sucrose nonfermentable family. Its mutations are linked to Cockayne syndrome phenotypes and classically are thought to be caused by defects in transcription-coupled repair, a subtype of DNA repair. Here we show that after UV-C irradiation, immediate early genes such as activating transcription factor 3 (ATF3) are overexpressed. Although the ATF3 target genes, including dihydrofolate reductase (DHFR), were unable to recover RNA synthesis in CSB-deficient cells, transcription was restored rapidly in normal cells. There the synthesis of DHFR mRNA restarts on the arrival of RNA polymerase II and CSB and the subsequent release of ATF3 from its cAMP response element/ATF target site. In CSB-deficient cells ATF3 remains bound to the promoter, thereby preventing the arrival of polymerase II and the restart of transcription. Silencing of ATF3, as well as stable introduction of wild-type CSB, restores RNA synthesis in UV-irradiated CSB cells, suggesting that, in addition to its role in DNA repair, CSB activity likely is involved in the reversal of inhibitory properties on a gene-promoter region. We present strong experimental data supporting our view that the transcriptional defects observed in UV-irradiated CSB cells are largely the result of a permanent transcriptional repression of a certain set of genes in addition to some defect in DNA repair.
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Vélez-Cruz R, Egly JM. Cockayne syndrome group B (CSB) protein: at the crossroads of transcriptional networks. Mech Ageing Dev 2013; 134:234-42. [PMID: 23562425 DOI: 10.1016/j.mad.2013.03.004] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2012] [Revised: 03/14/2013] [Accepted: 03/25/2013] [Indexed: 10/27/2022]
Abstract
Cockayne syndrome (CS) is a rare genetic disorder characterized by a variety of growth and developmental defects, photosensitivity, cachectic dwarfism, hearing loss, skeletal abnormalities, progressive neurological degeneration, and premature aging. CS arises due to mutations in the CSA and CSB genes. Both gene products are required for the transcription-coupled (TC) branch of the nucleotide excision repair (NER) pathway, however, the severe phenotype of CS patients is hard to reconcile with a sole defect in TC-NER. Studies using cells from patients and mouse models have shown that the CSB protein is involved in a variety of cellular pathways and plays a major role in the cellular response to stress. CSB has been shown to regulate processes such as the transcriptional recovery after DNA damage, the p53 transcriptional response, the response to hypoxia, the response to insulin-like growth factor-1 (IGF-1), transactivation of nuclear receptors, transcription of housekeeping genes and the transcription of rDNA. Some of these processes are also affected in combined XP/CS patients. These new advances in the function(s) of CSB shed light onto the etiology of the clinical features observed in CS patients and could potentially open therapeutic avenues for these patients in the future. Moreover, the study of CS could further our knowledge of the aging process.
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Affiliation(s)
- Renier Vélez-Cruz
- Department of Functional Genomics and Cancer, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), CNRS/INSERM/Université de Strasbourg, BP 163, 67404 Illkirch Cedex, C. U. Strasbourg, France.
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25
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McKay BC, Cabrita MA. Arresting transcription and sentencing the cell: the consequences of blocked transcription. Mech Ageing Dev 2013; 134:243-52. [PMID: 23542592 DOI: 10.1016/j.mad.2013.03.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2012] [Revised: 02/16/2013] [Accepted: 03/16/2013] [Indexed: 10/27/2022]
Abstract
Bulky DNA adducts induced by agents like ultraviolet light, cisplatin and oxidative metabolism pose a block to elongation by RNA polymerase II (RNAPII). The arrested RNAPII can initiate the repair of transcription-blocking DNA lesions by transcription-coupled nucleotide excision repair (TC-NER) to permit efficient recovery of mRNA synthesis while widespread sustained transcription blocks lead to apoptosis. Therefore, RNAPII serves as a processive DNA damage sensor that identifies transcription-blocking DNA lesions. Cockayne syndrome (CS) is an autosomal recessive disorder characterized by a complex phenotype that includes clinical photosensitivity, progressive neurological degeneration and premature-aging. CS is associated with defects in TC-NER and the recovery of mRNA synthesis, making CS cells exquisitely sensitive to a variety of DNA damaging agents. These defects in the coupling of repair and transcription appear to underlie some of the complex clinical features of CS. Recent insight into the consequences of blocked transcription and their relationship to CS will be discussed.
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Affiliation(s)
- Bruce C McKay
- Cancer Therapeutics Program, Ottawa Hospital Research Institute, Canada.
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