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Tomoszková S, Škarda J, Lipina R. Potential Diagnostic and Clinical Significance of Selected Genetic Alterations in Glioblastoma. Int J Mol Sci 2024; 25:4438. [PMID: 38674026 PMCID: PMC11050250 DOI: 10.3390/ijms25084438] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2024] [Revised: 04/08/2024] [Accepted: 04/16/2024] [Indexed: 04/28/2024] Open
Abstract
Glioblastoma is currently considered the most common and, unfortunately, also the most aggressive primary brain tumor, with the highest morbidity and mortality rates. The average survival of patients diagnosed with glioblastoma is 14 months, and only 2% of patients survive 3 years after surgery. Based on our clinical experience and knowledge from extensive clinical studies, survival is mainly related to the molecular biological properties of glioblastoma, which are of interest to the general medical community. Our study examined a total of 71 retrospective studies published from 2016 through 2022 and available on PubMed that deal with mutations of selected genes in the pathophysiology of GBM. In conclusion, we can find other mutations within a given gene group that have different effects on the prognosis and quality of survival of a patient with glioblastoma. These mutations, together with the associated mutations of other genes, as well as intratumoral heterogeneity itself, offer enormous potential for further clinical research and possible application in therapeutic practice.
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Affiliation(s)
- Silvia Tomoszková
- Neurosurgery Clinic, University Hospital Ostrava, 17. listopadu 1790/5, 708 00 Ostrava, Czech Republic;
- Medical Faculty, University of Ostrava, Syllabova 19, 703 00 Ostrava, Czech Republic;
| | - Jozef Škarda
- Medical Faculty, University of Ostrava, Syllabova 19, 703 00 Ostrava, Czech Republic;
- Institute of Molecular and Clinical Pathology and Medical Genetics, University Hospital Ostrava, 17. listopadu 1790/5, 708 00 Ostrava, Czech Republic
| | - Radim Lipina
- Neurosurgery Clinic, University Hospital Ostrava, 17. listopadu 1790/5, 708 00 Ostrava, Czech Republic;
- Medical Faculty, University of Ostrava, Syllabova 19, 703 00 Ostrava, Czech Republic;
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2
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Gaspar TB, Jesus TT, Azevedo MT, Macedo S, Soares MA, Martins RS, Leite R, Rodrigues L, Rodrigues DF, Cardoso L, Borges I, Canberk S, Gärtner F, Miranda-Alves L, Lopes JM, Soares P, Vinagre J. Generation of an Obese Diabetic Mouse Model upon Conditional Atrx Disruption. Cancers (Basel) 2023; 15:cancers15113018. [PMID: 37296979 DOI: 10.3390/cancers15113018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Revised: 05/15/2023] [Accepted: 05/30/2023] [Indexed: 06/12/2023] Open
Abstract
Atrx loss was recently ascertained as insufficient to drive pancreatic neuroendocrine tumour (PanNET) formation in mice islets. We have identified a preponderant role of Atrx in the endocrine dysfunction in a Rip-Cre;AtrxKO genetically engineered mouse model (GEMM). To validate the impact of a different Cre-driver line, we used similar methodologies and characterised the Pdx1-Cre;AtrxKO (P.AtrxKO) GEMM to search for PanNET formation and endocrine fitness disruption for a period of up to 24 months. Male and female mice presented different phenotypes. Compared to P.AtrxWT, P.AtrxHOM males were heavier during the entire study period, hyperglycaemic between 3 and 12 mo., and glucose intolerant only from 6 mo.; in contrast, P.AtrxHOM females started exhibiting increased weight gains later (after 6 mo.), but diabetes or glucose intolerance was detected by 3 mo. Overall, all studied mice were overweight or obese from early ages, which challenged the histopathological evaluation of the pancreas and liver, especially after 12 mo. Noteworthily, losing Atrx predisposed mice to an increase in intrapancreatic fatty infiltration (FI), peripancreatic fat deposition, and macrovesicular steatosis. As expected, no animal developed PanNETs. An obese diabetic GEMM of disrupted Atrx is presented as potentially useful for metabolic studies and as a putative candidate for inserting additional tumourigenic genetic events.
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Affiliation(s)
- Tiago Bordeira Gaspar
- Instituto de Investigação e Inovação em Saúde (i3S), University of Porto, 4200-135 Porto, Portugal
- Institute of Molecular Pathology and Immunology of the University of Porto (IPATIMUP), 4200-135 Porto, Portugal
- Institute of Biomedical Sciences Abel Salazar (ICBAS), University of Porto, 4050-313 Porto, Portugal
- Faculty of Medicine of the University of Porto (FMUP), 4200-319 Porto, Portugal
| | - Tito Teles Jesus
- Instituto de Investigação e Inovação em Saúde (i3S), University of Porto, 4200-135 Porto, Portugal
- Institute of Molecular Pathology and Immunology of the University of Porto (IPATIMUP), 4200-135 Porto, Portugal
| | - Maria Teresa Azevedo
- Instituto de Investigação e Inovação em Saúde (i3S), University of Porto, 4200-135 Porto, Portugal
- Institute of Molecular Pathology and Immunology of the University of Porto (IPATIMUP), 4200-135 Porto, Portugal
| | - Sofia Macedo
- Instituto de Investigação e Inovação em Saúde (i3S), University of Porto, 4200-135 Porto, Portugal
- Institute of Molecular Pathology and Immunology of the University of Porto (IPATIMUP), 4200-135 Porto, Portugal
- Institute of Biomedical Sciences Abel Salazar (ICBAS), University of Porto, 4050-313 Porto, Portugal
- Faculty of Medicine of the University of Porto (FMUP), 4200-319 Porto, Portugal
| | - Mariana Alves Soares
- Instituto de Investigação e Inovação em Saúde (i3S), University of Porto, 4200-135 Porto, Portugal
- Institute of Molecular Pathology and Immunology of the University of Porto (IPATIMUP), 4200-135 Porto, Portugal
- Laboratório de Endocrinologia Experimental (LEEx), Instituto de Ciências Biomédicas (ICB), Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, Brazil
- Programa de Pós-Graduação em Endocrinologia, Faculdade de Medicina, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, Brazil
| | - Rui Sousa Martins
- Instituto de Investigação e Inovação em Saúde (i3S), University of Porto, 4200-135 Porto, Portugal
- Institute of Molecular Pathology and Immunology of the University of Porto (IPATIMUP), 4200-135 Porto, Portugal
- Faculty of Sciences of the University of Porto (FCUP), 4169-007 Porto, Portugal
| | - Rúben Leite
- Instituto de Investigação e Inovação em Saúde (i3S), University of Porto, 4200-135 Porto, Portugal
- Institute of Molecular Pathology and Immunology of the University of Porto (IPATIMUP), 4200-135 Porto, Portugal
- School of Health (ESS), Polytechnic Institute of Porto (IPP), Rua Dr. António Bernardino de Almeida, 4200-072 Porto, Portugal
| | - Lia Rodrigues
- Instituto de Investigação e Inovação em Saúde (i3S), University of Porto, 4200-135 Porto, Portugal
- Institute of Molecular Pathology and Immunology of the University of Porto (IPATIMUP), 4200-135 Porto, Portugal
| | - Daniela Ferreira Rodrigues
- Instituto de Investigação e Inovação em Saúde (i3S), University of Porto, 4200-135 Porto, Portugal
- Institute of Molecular and Cell Biology (IBMC), University of Porto, 4200-135 Porto, Portugal
| | - Luís Cardoso
- Instituto de Investigação e Inovação em Saúde (i3S), University of Porto, 4200-135 Porto, Portugal
- Institute of Molecular Pathology and Immunology of the University of Porto (IPATIMUP), 4200-135 Porto, Portugal
- Department of Endocrinology, Diabetes and Metabolism, Centro Hospitalar e Universitário de Coimbra, 3000-075 Coimbra, Portugal
| | - Inês Borges
- Centro de Diagnóstico Veterinário (Cedivet), 4200-071 Porto, Portugal
| | - Sule Canberk
- Instituto de Investigação e Inovação em Saúde (i3S), University of Porto, 4200-135 Porto, Portugal
- Institute of Molecular Pathology and Immunology of the University of Porto (IPATIMUP), 4200-135 Porto, Portugal
- Institute of Biomedical Sciences Abel Salazar (ICBAS), University of Porto, 4050-313 Porto, Portugal
- Faculty of Medicine of the University of Porto (FMUP), 4200-319 Porto, Portugal
| | - Fátima Gärtner
- Instituto de Investigação e Inovação em Saúde (i3S), University of Porto, 4200-135 Porto, Portugal
- Institute of Molecular Pathology and Immunology of the University of Porto (IPATIMUP), 4200-135 Porto, Portugal
| | - Leandro Miranda-Alves
- Laboratório de Endocrinologia Experimental (LEEx), Instituto de Ciências Biomédicas (ICB), Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, Brazil
- Programa de Pós-Graduação em Endocrinologia, Faculdade de Medicina, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, Brazil
| | - José Manuel Lopes
- Instituto de Investigação e Inovação em Saúde (i3S), University of Porto, 4200-135 Porto, Portugal
- Institute of Molecular Pathology and Immunology of the University of Porto (IPATIMUP), 4200-135 Porto, Portugal
- Faculty of Medicine of the University of Porto (FMUP), 4200-319 Porto, Portugal
- Department of Pathology, Centro Hospitalar Universitário de São João (CHUSJ), 4200-319 Porto, Portugal
| | - Paula Soares
- Instituto de Investigação e Inovação em Saúde (i3S), University of Porto, 4200-135 Porto, Portugal
- Institute of Molecular Pathology and Immunology of the University of Porto (IPATIMUP), 4200-135 Porto, Portugal
- Faculty of Medicine of the University of Porto (FMUP), 4200-319 Porto, Portugal
| | - João Vinagre
- Instituto de Investigação e Inovação em Saúde (i3S), University of Porto, 4200-135 Porto, Portugal
- Institute of Molecular Pathology and Immunology of the University of Porto (IPATIMUP), 4200-135 Porto, Portugal
- Faculty of Medicine of the University of Porto (FMUP), 4200-319 Porto, Portugal
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3
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Pang Y, Chen X, Ji T, Cheng M, Wang R, Zhang C, Liu M, Zhang J, Zhong C. The Chromatin Remodeler ATRX: Role and Mechanism in Biology and Cancer. Cancers (Basel) 2023; 15:cancers15082228. [PMID: 37190157 DOI: 10.3390/cancers15082228] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Revised: 03/30/2023] [Accepted: 04/06/2023] [Indexed: 05/17/2023] Open
Abstract
The alpha-thalassemia mental retardation X-linked (ATRX) syndrome protein is a chromatin remodeling protein that primarily promotes the deposit of H3.3 histone variants in the telomere area. ATRX mutations not only cause ATRX syndrome but also influence development and promote cancer. The primary molecular characteristics of ATRX, including its molecular structures and normal and malignant biological roles, are reviewed in this article. We discuss the role of ATRX in its interactions with the histone variant H3.3, chromatin remodeling, DNA damage response, replication stress, and cancers, particularly gliomas, neuroblastomas, and pancreatic neuroendocrine tumors. ATRX is implicated in several important cellular processes and serves a crucial function in regulating gene expression and genomic integrity throughout embryogenesis. However, the nature of its involvement in the growth and development of cancer remains unknown. As mechanistic and molecular investigations on ATRX disclose its essential functions in cancer, customized therapies targeting ATRX will become accessible.
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Affiliation(s)
- Ying Pang
- Department of Neurosurgery, Shanghai East Hospital, School of Medicine, Tongji University, 150 Jimo Road, Shanghai 200120, China
| | - Xu Chen
- Department of Neurosurgery, Shanghai East Hospital, School of Medicine, Tongji University, 150 Jimo Road, Shanghai 200120, China
| | - Tongjie Ji
- Department of Neurosurgery, Shanghai East Hospital, School of Medicine, Tongji University, 150 Jimo Road, Shanghai 200120, China
| | - Meng Cheng
- Department of Neurosurgery, Shanghai East Hospital, School of Medicine, Tongji University, 150 Jimo Road, Shanghai 200120, China
| | - Rui Wang
- Department of Neurosurgery, Shanghai East Hospital, School of Medicine, Tongji University, 150 Jimo Road, Shanghai 200120, China
| | - Chunyu Zhang
- Department of Neurosurgery, Shanghai East Hospital, School of Medicine, Tongji University, 150 Jimo Road, Shanghai 200120, China
| | - Min Liu
- Department of Neurosurgery, Shanghai East Hospital, School of Medicine, Tongji University, 150 Jimo Road, Shanghai 200120, China
| | - Jing Zhang
- Department of Neurosurgery, Shanghai East Hospital, School of Medicine, Tongji University, 150 Jimo Road, Shanghai 200120, China
- Institute for Advanced Study, Tongji University, 1239 Siping Road, Shanghai 200092, China
| | - Chunlong Zhong
- Department of Neurosurgery, Shanghai East Hospital, School of Medicine, Tongji University, 150 Jimo Road, Shanghai 200120, China
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Clatterbuck Soper SF, Meltzer PS. ATRX/DAXX: Guarding the Genome against the Hazards of ALT. Genes (Basel) 2023; 14:genes14040790. [PMID: 37107548 PMCID: PMC10137841 DOI: 10.3390/genes14040790] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Revised: 03/21/2023] [Accepted: 03/22/2023] [Indexed: 03/29/2023] Open
Abstract
Proliferating cells must enact a telomere maintenance mechanism to ensure genomic stability. In a subset of tumors, telomeres are maintained not by telomerase, but through a homologous recombination-based mechanism termed Alternative Lengthening of Telomeres or ALT. The ALT process is linked to mutations in the ATRX/DAXX/H3.3 histone chaperone complex. This complex is responsible for depositing non-replicative histone variant H3.3 at pericentric and telomeric heterochromatin but has also been found to have roles in ameliorating replication in repeat sequences and in promoting DNA repair. In this review, we will discuss ways in which ATRX/DAXX helps to protect the genome, and how loss of this complex allows ALT to take hold.
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Huang J, Lu R, Zhong D, Weng Y, Liao L. A Novel Necroptosis-Associated IncRNAs Signature for Prognosis of Head and Neck Squamous Cell Carcinoma. Front Genet 2022; 13:907392. [PMID: 35754839 PMCID: PMC9213787 DOI: 10.3389/fgene.2022.907392] [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: 03/29/2022] [Accepted: 05/04/2022] [Indexed: 11/13/2022] Open
Abstract
Purpose: The prognosis of head and neck squamous cell carcinoma (HNSCC) is poor. Necroptosis is a novel programmed form of necrotic cell death. The prognostic value of necroptosis-associated lncRNAs expression in HNSCC has not been explored. Methods: We downloaded mRNA expression data of HNSCC patients from TCGA databases. Prognostic lncRNAs were identified by univariate Cox regression. LASSO was used to establish a model with necroptosis-related lncRNAs. Kaplan-Meier analysis and ROC were applied to verify the model. Finally, functional studies including gene set enrichment analyses, immune microenvironment analysis, and anti-tumor compound IC50 prediction were performed. Results: We identified 1,117 necroptosis-related lncRNAs. The Cox regression showed 55 lncRNAs were associated with patient survival (p < 0.05). The risk model of 24- lncRNAs signature categorized patients into high and low risk groups. The patients in the low-risk group survived longer than the high-risk group (p < 0.001). Validation assays including ROC curve, nomogram and correction curves confirmed the prediction capability of the 24-lncRNA risk mode. Functional studies showed the two patient groups had distinct immunity conditions and IC50. Conclusion: The 24-lncRNA model has potential to guide treatment of HNSCC. Future clinical studies are needed to verify the model.
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Affiliation(s)
- Jing Huang
- Department of Pharmacy, Fujian Medical University Cancer Hospital and Fujian Cancer Hospital, Fuzhou, China
| | - Rong Lu
- Department of Laboratory Medicine, The First Affiliated Hospital of Xiamen University, Xiamen Key Laboratory of Genetic Testing, School of Medicine, Xiamen University, Xiamen, China
| | - Dongta Zhong
- Department of Medical Oncology, Union Hospital of Fujian Medical University, Fuzhou, China
| | - Youliang Weng
- Department of Radiation Oncology, Fujian Medical University Cancer Hospital and Fujian Cancer Hospital, Fuzhou 350014, China
| | - Lianming Liao
- Center of Laboratory Medicine, Union Hospital of Fujian Medical University, Fuzhou, China
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Wen T, Chen QY. Dynamic Activity of Histone H3-Specific Chaperone Complexes in Oncogenesis. Front Oncol 2022; 11:806974. [PMID: 35087762 PMCID: PMC8786718 DOI: 10.3389/fonc.2021.806974] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Accepted: 12/15/2021] [Indexed: 11/30/2022] Open
Abstract
Canonical histone H3.1 and variant H3.3 deposit at different sites of the chromatin via distinct histone chaperones. Histone H3.1 relies on chaperone CAF-1 to mediate replication-dependent nucleosome assembly during S-phase, while H3.3 variant is regulated and incorporated into the chromatin in a replication-independent manner through HIRA and DAXX/ATRX. Current literature suggests that dysregulated expression of histone chaperones may be implicated in tumor progression. Notably, ectopic expression of CAF-1 can promote a switch between canonical H3.1 and H3 variants in the chromatin, impair the chromatic state, lead to chromosome instability, and impact gene transcription, potentially contributing to carcinogenesis. This review focuses on the chaperone proteins of H3.1 and H3.3, including structure, regulation, as well as their oncogenic and tumor suppressive functions in tumorigenesis.
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Affiliation(s)
- Ting Wen
- Department of Cell Biology and Genetics, School of Basic Medical Sciences, Xi'an Jiaotong University, Xi'an, China
| | - Qiao Yi Chen
- Department of Cell Biology and Genetics, School of Basic Medical Sciences, Xi'an Jiaotong University, Xi'an, China
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The Multiple Facets of ATRX Protein. Cancers (Basel) 2021; 13:cancers13092211. [PMID: 34062956 PMCID: PMC8124985 DOI: 10.3390/cancers13092211] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Revised: 04/30/2021] [Accepted: 05/02/2021] [Indexed: 12/21/2022] Open
Abstract
Simple Summary The gene encoding for the epigenetic regulator ATRX is gaining a prominent position among the most important oncosuppressive genes of the human genome. ATRX gene somatic mutations are found across a number of diverse cancer types, suggesting its relevance in tumor induction and progression. In the present review, the multiple activities of ATRX protein are described in the light of the most recent literature available highlighting its multifaceted role in the caretaking of the human genome. Abstract ATRX gene codifies for a protein member of the SWI-SNF family and was cloned for the first time over 25 years ago as the gene responsible for a rare developmental disorder characterized by α-thalassemia and intellectual disability called Alpha Thalassemia/mental Retardation syndrome X-linked (ATRX) syndrome. Since its discovery as a helicase involved in alpha-globin gene transcriptional regulation, our understanding of the multiple roles played by the ATRX protein increased continuously, leading to the recognition of this multifaceted protein as a central “caretaker” of the human genome involved in cancer suppression. In this review, we report recent advances in the comprehension of the ATRX manifold functions that encompass heterochromatin epigenetic regulation and maintenance, telomere function, replicative stress response, genome stability, and the suppression of endogenous transposable elements and exogenous viral genomes.
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Meyer-Nava S, Torres A, Zurita M, Valadez-Graham V. Molecular effects of dADD1 misexpression in chromatin organization and transcription. BMC Mol Cell Biol 2020; 21:17. [PMID: 32293240 PMCID: PMC7092677 DOI: 10.1186/s12860-020-00257-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Accepted: 03/04/2020] [Indexed: 12/14/2022] Open
Abstract
Background dADD1 and dXNP proteins are the orthologs in Drosophila melanogaster of the ADD and SNF2 domains, respectively, of the ATRX vertebrate’s chromatin remodeler, they suppress position effect variegation phenotypes and participate in heterochromatin maintenance. Results We performed a search in human cancer databases and found that ATRX protein levels were elevated in more than 4.4% of the samples analyzed. Using the Drosophila model, we addressed the effects of over and under-expression of dADD1 proteins in polytene cells. Elevated levels of dADD1 in fly tissues caused different phenotypes, such as chromocenter disruption and loss of banding pattern at the chromosome arms. Analyses of the heterochromatin maintenance protein HP1a, the dXNP ATPase and the histone post-translational modification H3K9me3 revealed changes in their chromatin localization accompanied by mild transcriptional defects of genes embedded in heterochromatic regions. Furthermore, the expression of heterochromatin embedded genes in null dadd1 organisms is lower than in the wild-type conditions. Conclusion These data indicate that dADD1 overexpression induces chromatin changes, probably affecting the stoichiometry of HP1a containing complexes that lead to transcriptional and architectural changes. Our results place dADD1 proteins as important players in the maintenance of chromatin architecture and heterochromatic gene expression.
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Affiliation(s)
- Silvia Meyer-Nava
- Instituto de Biotecnología. Universidad Nacional Autónoma de México, Campus Morelos, Av. Universidad 2001, C.P, 62210, Cuernavaca, Morelos, Mexico
| | - Amada Torres
- Instituto de Biotecnología. Universidad Nacional Autónoma de México, Campus Morelos, Av. Universidad 2001, C.P, 62210, Cuernavaca, Morelos, Mexico
| | - Mario Zurita
- Instituto de Biotecnología. Universidad Nacional Autónoma de México, Campus Morelos, Av. Universidad 2001, C.P, 62210, Cuernavaca, Morelos, Mexico
| | - Viviana Valadez-Graham
- Instituto de Biotecnología. Universidad Nacional Autónoma de México, Campus Morelos, Av. Universidad 2001, C.P, 62210, Cuernavaca, Morelos, Mexico.
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Abstract
ATRX was identified over 20 years ago as the gene responsible for a rare developmental disorder characterized by α-thalassemia and intellectual disability. Similarities to the sucrose nonfermentable SNF2 type chromatin remodelers initially suggested a role in transcriptional regulation. However, over the last years, our knowledge of the epigenetic activities of ATRX has expanded steadily. Recent exciting discoveries have propelled ATRX into the limelight of chromatin and telomere biology, development and cancer research. This review summarizes recent breakthroughs in understanding ATRX function in heterochromatin structure, genome stability and its frequent dysregulation in a variety of cancers.
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Affiliation(s)
- L Ashley Watson
- Departments of Paediatrics, Biochemistry & Oncology, University of Western Ontario, Victoria Research Laboratories, 800 Commissioners Road East, London, Canada.,Children's Health Research Institute, London, Canada.,Lawson Health Research Institute, London, Canada
| | - Hannah Goldberg
- Departments of Paediatrics, Biochemistry & Oncology, University of Western Ontario, Victoria Research Laboratories, 800 Commissioners Road East, London, Canada.,Children's Health Research Institute, London, Canada.,Lawson Health Research Institute, London, Canada
| | - Nathalie G Bérubé
- Departments of Paediatrics, Biochemistry & Oncology, University of Western Ontario, Victoria Research Laboratories, 800 Commissioners Road East, London, Canada.,Children's Health Research Institute, London, Canada.,Lawson Health Research Institute, London, Canada
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10
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Meeker A, Heaphy C. Gastroenteropancreatic endocrine tumors. Mol Cell Endocrinol 2014; 386:101-20. [PMID: 23906538 DOI: 10.1016/j.mce.2013.07.015] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2013] [Revised: 07/19/2013] [Accepted: 07/22/2013] [Indexed: 02/06/2023]
Abstract
Gastroenteropancreatic endocrine tumors (GEP-NETs) are relatively uncommon; comprising approximately 0.5% of all human cancers. Although they often exhibit relatively indolent clinical courses, GEP-NETs have the potential for lethal progression. Due to their scarcity and various technical challenges, GEP-NETs have been understudied. As a consequence, we have few diagnostic, prognostic and predictive biomarkers for these tumors. Early detection and surgical removal is currently the only reliable curative treatment for GEP-NET patients; many of whom, unfortunately, present with advanced disease. Here, we review the genetics and epigenetics of GEP-NETs. The last few years have witnessed unprecedented technological advances in these fields, and their application to GEP-NETS has already led to important new information on the molecular abnormalities underlying them. As outlined here, we expect that "omics" studies will provide us with new diagnostic and prognostic biomarkers, inform the development of improved pre-clinical models, and identify novel therapeutic targets for GEP-NET patients.
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Affiliation(s)
- Alan Meeker
- The Johns Hopkins University School of Medicine, Department of Pathology, Bond Street Research Annex Bldg., Room B300, 411 North Caroline Street, Baltimore, MD 21231, United States.
| | - Christopher Heaphy
- The Johns Hopkins University School of Medicine, Department of Pathology, Bond Street Research Annex Bldg., Room B300, 411 North Caroline Street, Baltimore, MD 21231, United States
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11
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Ratnakumar K, Bernstein E. ATRX: the case of a peculiar chromatin remodeler. Epigenetics 2012; 8:3-9. [PMID: 23249563 DOI: 10.4161/epi.23271] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The SWI/SNF-like chromatin remodeler ATRX has recently garnered renewed attention. ATRX mutations were first identified in patients bearing the syndrome after which it is named, alpha thalassemia/mental retardation, X-linked. While ATRX has long been implicated in transcriptional regulation through multiple mechanisms, recent studies have identified a role for ATRX in the regulation of histone variant deposition. In addition, current reports describe ATRX to be mutated at high percentages in multiple tumor types, suggestive of a potential 'driver' role in cancer. Here we discuss the numerous and seemingly diverse roles for ATRX in transcriptional regulation and histone deposition and suggest that ATRX's effects are mediated by its regulation of histones within the chromatin template.
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Affiliation(s)
- Kajan Ratnakumar
- Department of Oncological Sciences, Mount Sinai School of Medicine, New York, NY, USA
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12
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Gibbons RJ. α-Thalassemia, mental retardation, and myelodysplastic syndrome. Cold Spring Harb Perspect Med 2012; 2:2/10/a011759. [PMID: 23028133 DOI: 10.1101/cshperspect.a011759] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
This article describes three rare syndromes in which the presence of α-thalassemia provided an important clue to the molecular basis of the underlying condition. It exemplifies how rare diseases allied with careful clinical observation can lead to important biological principles. Two of the syndromes, ATR-16 and ATR-X, are characterized by α-thalassemia in association with multiple developmental abnormalities including mental retardation. The third condition, ATMDS, is an acquired disorder in which α-thalassemia arises in the context of myelodysplasia. Intriguingly, mutations in the chromatin remodeling factor, ATRX, are common to both ATR-X syndrome and ATMDS.
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Affiliation(s)
- Richard J Gibbons
- MRC Molecular Haematology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DS, United Kingdom.
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13
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Tsend-Ayush E, Lim SL, Pask AJ, Hamdan DDM, Renfree MB, Grützner F. Characterisation of ATRX, DMRT1, DMRT7 and WT1 in the platypus (Ornithorhynchus anatinus). Reprod Fertil Dev 2009; 21:985-91. [DOI: 10.1071/rd09090] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2009] [Accepted: 08/28/2009] [Indexed: 11/23/2022] Open
Abstract
One of the most puzzling aspects of monotreme reproductive biology is how they determine sex in the absence of the SRY gene that triggers testis development in most other mammals. Although monotremes share a XX female/XY male sex chromosome system with other mammals, their sex chromosomes show homology to the chicken Z chromosome, including the DMRT1 gene, which is a dosage-dependent sex determination gene in birds. In addition, monotremes feature an extraordinary multiple sex chromosome system. However, no sex determination gene has been identified as yet on any of the five X or five Y chromosomes and there is very little knowledge about the conservation and function of other known genes in the monotreme sex determination and differentiation pathway. We have analysed the expression pattern of four evolutionarily conserved genes that are important at different stages of sexual development in therian mammals. DMRT1 is a conserved sex-determination gene that is upregulated in the male developing gonad in vertebrates, while DMRT7 is a mammal-specific spermatogenesis gene. ATRX, a chromatin remodelling protein, lies on the therian X but there is a testis-expressed Y-copy in marsupials. However, in monotremes, the ATRX orthologue is autosomal. WT1 is an evolutionarily conserved gene essential for early gonadal formation in both sexes and later in testis development. We show that these four genes in the adult platypus have the same expression pattern as in other mammals, suggesting that they have a conserved role in sexual development independent of genomic location.
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14
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Baker LA, Allis CD, Wang GG. PHD fingers in human diseases: disorders arising from misinterpreting epigenetic marks. Mutat Res 2008; 647:3-12. [PMID: 18682256 PMCID: PMC2656448 DOI: 10.1016/j.mrfmmm.2008.07.004] [Citation(s) in RCA: 161] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2008] [Accepted: 07/04/2008] [Indexed: 12/14/2022]
Abstract
Histone covalent modifications regulate many, if not all, DNA-templated processes, including gene expression and DNA damage response. The biological consequences of histone modifications are mediated partially by evolutionarily conserved "reader/effector" modules that bind to histone marks in a modification- and context-specific fashion and subsequently enact chromatin changes or recruit other proteins to do so. Recently, the Plant Homeodomain (PHD) finger has emerged as a class of specialized "reader" modules that, in some instances, recognize the methylation status of histone lysine residues, such as histone H3 lysine 4 (H3K4). While mutations in catalytic enzymes that mediate the addition or removal of histone modifications (i.e., "writers" and "erasers") are already known to be involved in various human diseases, mutations in the modification-specific "reader" proteins are only beginning to be recognized as contributing to human diseases. For instance, point mutations, deletions or chromosomal translocations that target PHD fingers encoded by many genes (such as recombination activating gene 2 (RAG2), Inhibitor of Growth (ING), nuclear receptor-binding SET domain-containing 1 (NSD1) and Alpha Thalassaemia and Mental Retardation Syndrome, X-linked (ATRX)) have been associated with a wide range of human pathologies including immunological disorders, cancers, and neurological diseases. In this review, we will discuss the structural features of PHD fingers as well as the diseases for which direct mutation or dysregulation of the PHD finger has been reported. We propose that misinterpretation of the epigenetic marks may serve as a general mechanism for human diseases of this category. Determining the regulatory roles of histone covalent modifications in the context of human disease will allow for a more thorough understanding of normal and pathological development, and may provide innovative therapeutic strategies wherein "chromatin readers" stand as potential drug targets.
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Affiliation(s)
- Lindsey A. Baker
- Laboratory of Chromatin Biology & Epigenetics, The Rockefeller University, New York, NY 10065
| | - C. David Allis
- Laboratory of Chromatin Biology & Epigenetics, The Rockefeller University, New York, NY 10065
| | - Gang G. Wang
- Laboratory of Chromatin Biology & Epigenetics, The Rockefeller University, New York, NY 10065
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15
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Muers MR, Sharpe JA, Garrick D, Sloane-Stanley J, Nolan PM, Hacker T, Wood WG, Higgs DR, Gibbons RJ. Defining the cause of skewed X-chromosome inactivation in X-linked mental retardation by use of a mouse model. Am J Hum Genet 2007; 80:1138-49. [PMID: 17503331 PMCID: PMC1867101 DOI: 10.1086/518369] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2007] [Accepted: 03/22/2007] [Indexed: 11/03/2022] Open
Abstract
Extreme skewing of X-chromosome inactivation (XCI) is rare in the normal female population but is observed frequently in carriers of some X-linked mutations. Recently, it has been shown that various forms of X-linked mental retardation (XLMR) have a strong association with skewed XCI in female carriers, but the mechanisms underlying this skewing are unknown. ATR-X syndrome, caused by mutations in a ubiquitously expressed, chromatin-associated protein, provides a clear example of XLMR in which phenotypically normal female carriers virtually all have highly skewed XCI biased against the X chromosome that harbors the mutant allele. Here, we have used a mouse model to understand the processes causing skewed XCI. In female mice heterozygous for a null Atrx allele, we found that XCI is balanced early in embryogenesis but becomes skewed over the course of development, because of selection favoring cells expressing the wild-type Atrx allele. Unexpectedly, selection does not appear to be the result of general cellular-viability defects in Atrx-deficient cells, since it is restricted to specific stages of development and is not ongoing throughout the life of the animal. Instead, there is evidence that selection results from independent tissue-specific effects. This illustrates an important mechanism by which skewed XCI may occur in carriers of XLMR and provides insight into the normal role of ATRX in regulating cell fate.
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Affiliation(s)
- Mary R Muers
- MRC Molecular Haematology Unit, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, Oxford, UK
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16
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Lee NG, Hong YK, Yu SY, Han SY, Geum D, Cho KS. dXNP, aDrosophilahomolog of XNP/ATRX, induces apoptosis via Jun-N-terminal kinase activation. FEBS Lett 2007; 581:2625-32. [PMID: 17531976 DOI: 10.1016/j.febslet.2007.05.005] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2007] [Revised: 04/27/2007] [Accepted: 05/03/2007] [Indexed: 01/15/2023]
Abstract
XNP/ATRX, a causative gene of X-linked alpha-thalassemia/mental retardation syndrome, encodes an SNF2 family ATPase/helicase protein. To better understand the role of XNP/ATRX in development, we isolated and characterized a Drosophila XNP/ATRX homolog, dXNP, which contains highly conserved SNF2 and helicase domains. Ectopically expressed dXNP induced strong apoptosis in the developing eye and wing, but did not affect cell cycle progression or the expression of wingless and engrailed, essential regulators of development. The dXNP-induced apoptosis was strongly suppressed by DJNKK/hemipterous mutation, and dXNP increased JNK activity. Taken together, these results suggest that dXNP regulates apoptosis via JNK activation.
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Affiliation(s)
- Nam Gon Lee
- Department of Biological Sciences, Konkuk University, Seoul, Republic of Korea
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17
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Affiliation(s)
- Smita S Patel
- Department of Biochemistry, Robert Wood Johnson Medical School, University of Medicine and Dentistry of New Jersey, Piscataway, New Jersey 08854, USA.
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18
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Garinis GA, Mitchell JR, Moorhouse MJ, Hanada K, de Waard H, Vandeputte D, Jans J, Brand K, Smid M, van der Spek PJ, Hoeijmakers JHJ, Kanaar R, van der Horst GTJ. Transcriptome analysis reveals cyclobutane pyrimidine dimers as a major source of UV-induced DNA breaks. EMBO J 2005; 24:3952-62. [PMID: 16252008 PMCID: PMC1283948 DOI: 10.1038/sj.emboj.7600849] [Citation(s) in RCA: 123] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2005] [Accepted: 09/30/2005] [Indexed: 12/11/2022] Open
Abstract
Photolyase transgenic mice have opened new avenues to improve our understanding of the cytotoxic effects of ultraviolet (UV) light on skin by providing a means to selectively remove either cyclobutane pyrimidine dimers (CPDs) or pyrimidine (6-4) pyrimidone photoproducts. Here, we have taken a genomics approach to delineate pathways through which CPDs might contribute to the harmful effects of UV exposure. We show that CPDs, rather than other DNA lesions or damaged macromolecules, comprise the principal mediator of the cellular transcriptional response to UV. The most prominent pathway induced by CPDs is that associated with DNA double-strand break (DSB) signalling and repair. Moreover, we show that CPDs provoke accumulation of gamma-H2AX, P53bp1 and Rad51 foci as well as an increase in the amount of DSBs, which coincides with accumulation of cells in S phase. Thus, conversion of unrepaired CPD lesions into DNA breaks during DNA replication may comprise one of the principal instigators of UV-mediated cytotoxicity.
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Affiliation(s)
- George A Garinis
- Department of Cell Biology and Genetics, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - James R Mitchell
- Department of Cell Biology and Genetics, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Michael J Moorhouse
- Department of Bioinformatics, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Katsuhiro Hanada
- Department of Cell Biology and Genetics, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Harm de Waard
- Department of Cell Biology and Genetics, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Dimitri Vandeputte
- Department of Cell Biology and Genetics, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Judith Jans
- Department of Cell Biology and Genetics, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Karl Brand
- Department of Cell Biology and Genetics, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Marcel Smid
- Department of Medical Oncology, Josephine Nefkens Institute, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Peter J van der Spek
- Department of Bioinformatics, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Jan H J Hoeijmakers
- Department of Cell Biology and Genetics, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Roland Kanaar
- Department of Cell Biology and Genetics, Erasmus University Medical Center, Rotterdam, The Netherlands
- Department of Radiation Oncology, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Gijsbertus T J van der Horst
- Department of Cell Biology and Genetics, Erasmus University Medical Center, Rotterdam, The Netherlands
- Department of Cell Biology and Genetics, Center for Biomedical Genetics, Erasmus University Medical Center, PO Box 1738, 3000 DR Rotterdam, The Netherlands. Tel.: +31 10 408 7455; Fax: +31 10 408 9468; E-mail:
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19
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Bérubé NG, Mangelsdorf M, Jagla M, Vanderluit J, Garrick D, Gibbons RJ, Higgs DR, Slack RS, Picketts DJ. The chromatin-remodeling protein ATRX is critical for neuronal survival during corticogenesis. J Clin Invest 2005; 115:258-67. [PMID: 15668733 PMCID: PMC544602 DOI: 10.1172/jci22329] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2004] [Accepted: 11/30/2004] [Indexed: 12/18/2022] Open
Abstract
Mutations in genes encoding chromatin-remodeling proteins, such as the ATRX gene, underlie a number of genetic disorders including several X-linked mental retardation syndromes; however, the role of these proteins in normal CNS development is unknown. Here, we used a conditional gene-targeting approach to inactivate Atrx, specifically in the forebrain of mice. Loss of ATRX protein caused widespread hypocellularity in the neocortex and hippocampus and a pronounced reduction in forebrain size. Neuronal "birthdating" confirmed that fewer neurons reached the superficial cortical layers, despite normal progenitor cell proliferation. The loss of cortical mass resulted from a 12-fold increase in neuronal apoptosis during early stages of corticogenesis in the mutant animals. Moreover, cortical progenitors isolated from Atrx-null mice undergo enhanced apoptosis upon differentiation. Taken together, our results indicate that ATRX is a critical mediator of cell survival during early neuronal differentiation. Thus, increased neuronal loss may contribute to the severe mental retardation observed in human patients.
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Affiliation(s)
- Nathalie G Bérubé
- Molecular Medicine Programs, Ottawa Health Research Institute, Ottawa, Ontario, Canada
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20
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Bérubé NG, Mangelsdorf M, Jagla M, Vanderluit J, Garrick D, Gibbons RJ, Higgs DR, Slack RS, Picketts DJ. The chromatin-remodeling protein ATRX is critical for neuronal survival during corticogenesis. J Clin Invest 2005. [DOI: 10.1172/jci200522329] [Citation(s) in RCA: 138] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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21
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Park DJ, Pask AJ, Huynh K, Renfree MB, Harley VR, Graves JAM. Comparative analysis of ATRX, a chromatin remodeling protein. Gene 2004; 339:39-48. [PMID: 15363844 DOI: 10.1016/j.gene.2004.06.025] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2004] [Revised: 04/08/2004] [Accepted: 06/10/2004] [Indexed: 10/26/2022]
Abstract
The ATRX protein, associated with X-linked alpha-thalassaemia, mental retardation and developmental abnormalities including genital dysgenesis, has been proposed to function as a global transcriptional regulator within a multi-protein complex. However, an understanding of the composition and mechanics of this machinery has remained elusive. We applied inter-specific comparative analysis to identify conserved elements which may be involved in regulating the conformation of chromatin. As part of this study, we cloned and sequenced the entire translatable coding region (7.4 kb) of the ATRX gene from a model marsupial (tammar wallaby, Macropus eugenii). We identify an ATRX ancestral core, conserved between plants, fish and mammals, comprising the cysteine-rich and SWI2/SNF2 helicase-like regions and protein interaction domains. Our data are consistent with the model of the cysteine-rich region as a DNA-binding zinc finger adjacent to a protein-binding (plant homeodomain-like) domain. Alignment of vertebrate ATRX sequences highlights other conserved elements, including a negatively charged mammalian sequence which we propose to be involved in binding of positively charged histone tails.
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Affiliation(s)
- Daniel J Park
- Department of Zoology, The University of Melbourne, Gate 12 Royal Parade, Melbourne 3010, Australia.
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22
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Makishima H, Ishida F, Ito T, Kitano K, Ueno S, Ohmine K, Yamashita Y, Ota J, Ota M, Yamauchi K, Mano H. DNA microarray analysis of T cell-type lymphoproliferative disease of granular lymphocytes. Br J Haematol 2002; 118:462-9. [PMID: 12139733 DOI: 10.1046/j.1365-2141.2002.03646.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Lymphoproliferative disease of granular lymphocytes (LDGL) is characterized by the clonal proliferation of large granular lymphocytes of either T- or natural killer cell origin. To better understand the nature of T cell-type LDGL, we purified the CD4-CD8+ proliferative fractions from LDGL patients (n=4) and the surface marker-matched T cells isolated from healthy volunteers (n=4), and compared the expression profiles of 3456 genes using DNA microarray. Through this analysis, we identified a total of six genes whose expression was active in the LDGL T cells, but silent in the normal ones. Interestingly, expression of the gene for interleukin (IL) 1beta was specific to LDGL T cells, which was further confirmed by the examination of the serum level of IL-1beta protein. Given its important role in inflammatory reactions, the disease-specific expression of IL-1beta may have a causative relationship with the LDGL-associated rheumatoid arthritis. Spectratyping analysis of the T-cell receptor repertoire also proved the monoclonal or oligoclonal nature of LDGL cells. These data have shown that microarray analysis with a purified T-cell subset is an efficient approach to investigate the pathological condition of Tcell-type LDGL.
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Affiliation(s)
- Hideki Makishima
- Second Department of Internal Medicine, Shinshu University School of Medicine, 3-1-1 Asahi, Matsumoto, Nagano 390-8621, Japan
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23
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Ronen A, Glickman BW. Human DNA repair genes. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2001; 37:241-283. [PMID: 11317342 DOI: 10.1002/em.1033] [Citation(s) in RCA: 98] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
DNA repair systems are essential for the maintenance of genome integrity. Consequently, the disregulation of repair genes can be expected to be associated with significant, detrimental health effects, which can include an increased prevalence of birth defects, an enhancement of cancer risk, and an accelerated rate of aging. Although original insights into DNA repair and the genes responsible were largely derived from studies in bacteria and yeast, well over 125 genes directly involved in DNA repair have now been identified in humans, and their cDNA sequence established. These genes function in a diverse set of pathways that involve the recognition and removal of DNA lesions, tolerance to DNA damage, and protection from errors of incorporation made during DNA replication or DNA repair. Additional genes indirectly affect DNA repair, by regulating the cell cycle, ostensibly to provide an opportunity for repair or to direct the cell to apoptosis. For about 70 of the DNA repair genes listed in Table I, both the genomic DNA sequence and the cDNA sequence and chromosomal location have been elucidated. In 45 cases single-nucleotide polymorphisms have been identified and, in some cases, genetic variants have been associated with specific disorders. With the accelerating rate of gene discovery, the number of identified DNA repair genes and sequence variants is quickly rising. This report tabulates the current status of what is known about these genes. The report is limited to genes whose function is directly related to DNA repair.
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Affiliation(s)
- A Ronen
- Centre for Environmental Health, University of Victoria, Victoria, British Columbia, Canada.
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24
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Kulski JK, Ward BK. Cloning and characterization of a novel caprine genomic repetitive element that hybridizes with papillomavirus DNA. Electrophoresis 2000; 21:896-903. [PMID: 10768774 DOI: 10.1002/(sici)1522-2683(20000301)21:5<896::aid-elps896>3.0.co;2-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
A goat genomic library was screened by Southern blot hybridization at reduced stringency with a bovine papillomavirus type 5 (BPV 5) DNA probe in order to identify potential cellular and viral sequences related to the papillomavirus genome. A recombinant clone with an 8.5 kb genomic insert was found to contain a 1.3 kb PstI subfragment (designated as P1-1) that hybridized with the DNA of BPV 5, two murine papillomaviruses and human papillomavirus types 5 and 8, but not with DNA from another eight human and bovine papillomavirus types. Southern blot hybridization of the goat P1-1 DNA probe was restricted to a single 1.0 kb subfragment within the E1 open reading frame (ORF) of BPV 5 but produced multiple bands ranging between 1.0 and 9.0 kb when hybridized under stringent conditions with PstI-digested DNA obtained from different goat tissues. The genomic sequence of P1-1 has direct repeats of 10 and 13 nucleotides flanking 153 nucleotides, and 889 nucleotides of sequence, respectively, and an inverted repeat sequence of 11 nucleotides flanking a major ORF potentially coding for 244 residues. Potential splice acceptor and donor sites capable of joining with upstream and downstream exons are present within the major ORF. Sequence similarity between P1-1 and BPV 5 DNA at the nucleotide and amino acid level was limited to a stretch of 58 nucleotides which includes an oligopurine/pyrimidine tract. This region of similarity contains a predicted glutamic acid-rich domain. The P1-1 sequence is a novel repetitive element within the goat genome that is unrelated in sequence to papillomavirus DNA and to genomic sequences of mouse and man.
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Affiliation(s)
- J K Kulski
- Centre for Molecular Immunology and Instrumentation, Department of Microbiology, The University of Western Australia, Nedlands, Australia.
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25
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Abstract
In mammals the male sex determination switch is controlled by a single gene on the Y chromosome, SRY. SRY encodes a protein with an HMG-like DNA-binding domain, which probably acts as a local organizer of chromatin structure. It is believed to regulate downstream genes in the sex determination cascade, although no direct targets of SRY are clearly known. More genes in the pathway have been isolated through mutation approaches in mouse and human. At least three genes, SRY itself, SOX9, and DAX1, are dosage sensitive, providing molecular evidence that the sex determination step operates at a critical threshold. SRY initiates development of a testis from the bipotential cells of the early gonad. The dimorphic male and female pathways present a rare opportunity to link a pivotal gene in development with morphogenetic mechanisms that operate to pattern an organ and the differentiation of its cells. Mechanisms of testis organogenesis triggered downstream of SRY include pathways of cell signaling controlling cell reorganization, cell proliferation, cell migration, and vascularization.
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Affiliation(s)
- B Capel
- Department of Cell Biology, Duke University Medical Center, Durham, North Carolina 27710, USA.
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26
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Abstract
alpha-Thalassaemias are genetic defects extremely frequent in some populations and are characterized by the decrease or complete suppression of alpha-globin polypeptide chains. The gene cluster, which codes for and controls the production of these polypeptides, maps near the telomere of the short arm of chromosome 16, within a G + C rich and early-replicating DNA region. The genes expressed during the embryonic (zeta) or fetal and adult stage (alpha 2 and alpha 1) can be modified by point mutations which affect either the processing-translation of mRNA or make the polypeptide chains extremely unstable. Much more frequent are the deletions of variable size (from approximately 3 to more than 100 kb) which remove one or both alpha genes in cis or even the whole gene cluster. Deletions of a single gene are the result of unequal pairing during meiosis, followed by reciprocal recombination. These unequal cross-overs, which produce also alpha gene triplications and quadruplications, are made possible by the high degree of homology of the two alpha genes and of their flanking sequences. Other deletions involving one or more genes are due to recombinations which have taken place within non-homologous regions (illegitimate recombinations) or in DNA segments whose homology is limited to very short sequences. Particularly interesting are the deletions which eliminate large DNA areas 5' of zeta or of both alpha genes. These deletions do not include the structural genes but, nevertheless, suppress completely their expression. Larger deletions involving the tip of the short arm of chromosome 16 by truncation, interstitial deletions or translocations result in the contiguous gene syndrome ATR-16. In this complex syndrome alpha-thalassaemia is accompanied by mental retardation and variable dismorphic features. The study of mutations of the 5' upstream flanking region has led to the discovery of a DNA sequence, localized 40 kb upstream of the zeta-globin gene, which controls the expression of the alpha genes (alpha major regulatory element or HS-40). In the acquired variant of haemoglobin H (HbH) disease found in rare individuals with myelodysplastic disorders and in the X-linked mental retardation associated with alpha-thalassaemia, a profound reduction or absence of alpha gene expression has been observed, which is not accompanied by structural alterations of the coding or controlling regions of the alpha gene complex. Most probably the acquired alpha-thalassaemia is due to the lack of soluble activators (or presence of repressors) which act in trans and affect the expression of the homologous clusters and are coded by genes not (closely) linked to the alpha genes. The ATR-X syndrome results from mutations of the XH2 gene, located on the X chromosome (Xq13.3) and coding for a transacting factor which regulates gene expression. The interaction of the different alpha-thalassaemia determinants results in three phenotypes: the alpha-thalassaemic trait, clinically silent and presenting only limited alterations of haematological parameters, HbH disease, characterized by the development of a haemolytic anaemia of variable degree, and the (lethal) Hb Bart's hydrops fetalis syndrome. The diagnosis of alpha-thalassaemia due to deletions is implemented by the electrophoretic analysis of genomic DNA digested with restriction enzymes and hybridized with specific molecular probes. Recently polymerase chain reaction (PCR) based strategies have replaced the Southern blotting methodology. The straightforward identification of point mutations is carried out by the specific amplification of the alpha 2 or alpha 1 gene by PCR followed by the localization and identification of the mutation with a variety of screening systems (denaturing gradient gel electrophoresis (DGGE), single strand conformation polymorphisms (SSCP)) and direct sequencing.
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Affiliation(s)
- L F Bernini
- Institute of Human Genetics, Medical Faculty, University of Leiden, Sylvius Laboratory, The Netherlands
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27
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Villard L, Lossi AM, Cardoso C, Proud V, Chiaroni P, Colleaux L, Schwartz C, Fontés M. Determination of the genomic structure of the XNP/ATRX gene encoding a potential zinc finger helicase. Genomics 1997; 43:149-55. [PMID: 9244431 DOI: 10.1006/geno.1997.4793] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The XNP/ATR-X gene is involved in several X-linked mental retardation phenotypes: the ATR-X syndrome, the Juberg-Marsidi syndrome, and some severe mental retardation phenotypes without alpha-thalassemia. Using a vectorette strategy, we have identified and sequenced the intron/exon boundaries of this gene. The gene is composed of 35 exons. It encodes a potential protein of 2492 amino acids. A search of the databases identified three zinc finger motifs within the 5' end of the gene. Expression analysis in different tissues indicated that an alternative splicing event that involves exon 6 is occurring. One of these alternatively spliced transcripts is predominantly expressed in embryonic tissues. These data led us to search for mutations in the 5' region in ATRX patients without other mutations in the 3' region. In one patient a mutation was found in which part of exon 7 was removed from the XNP transcript, as a result of a mutation creating a novel splice site that is substituted for the natural splice site. This new splicing event removed one zinc finger motif. This is the first example of a mutation in XNP within the 5' coding region. It suggests that mutations will be predominantly found in the helicase region as well as in the zinc finger regions and leads us to propose a large screening of additional patients.
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Affiliation(s)
- L Villard
- Génétique Médicale et Développement, Faculté de Médecine de la Timone, INSERM U 406, Marseille, France
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28
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Abstract
Six known or predicted helicases that are mutated in human syndromes are now recognized. These syndromes include xeroderma pigmentosum, Cockayne's syndrome, trichothiodystrophy, Bloom's syndrome, Werner's syndrome, and alpha-thalassemia mental retardation on the X chromosome. The clinical abnormalities in these syndromes cover a broad spectrum, pointing to different cellular processes of DNA manipulation that are defective in these syndromes.
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Affiliation(s)
- N A Ellis
- Laboratory of Human Genetics, New York Blood Center, New York 10021, USA
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29
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Lynn S, Lai HT, Kao SM, Lai J, Jan KY. Cadmium inhibits DNA strand break rejoining in methyl methanesulfonate-treated CHO-K1 cells. Toxicol Appl Pharmacol 1997; 144:171-6. [PMID: 9169081 DOI: 10.1006/taap.1997.8116] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The cogenotoxicity of Cd has been recognized. This effect may stem from Cd inhibition of DNA repair. We studied the effects of Cd on DNA repair of methyl methanesulfonate (MMS)-damaged Chinese hamster ovary cells (CHO-K1) by single-cell alkaline electrophoresis. The results indicate that in the presence of Cd, DNA strand breaks accumulated in MMS-treated cells. Using hydroxyurea (Hu) plus cytosine-beta-D-arabinofuranoside (AraC) to block DNA polymerization, DNA strand breaks accumulated and Cd had little inhibitory effects on these accumulations. However, Cd inhibited the rejoining of these DNA strand breaks, which could be rejoined 6 hr after release from Hu plus AraC blockage. These results indicate that the potency of Cd inhibition of DNA repair replication and/or ligation may be greater than the inhibition of DNA adduct excision. To further elucidate this mechanism, we used an in vitro cell-free assay system to analyze the Cd effects on DNA repair synthesis, DNA polymerization, and DNA ligation. We have shown a dose-dependent inhibition of these three activities by Cd in CHO-K1 cell extract. The IC50s of Cd were 55, 26, and 10 microM, respectively. Moreover, Cd inhibition of DNA ligation in cell extract could be recovered partially by thiol compounds such as glutathione, beta-mercaptoethanol, dithiothreitol, and metallothionein. Since both in vivo and in vitro studies demonstrated that Cd was more effectively involved in interfering with the DNA ligation step and that thiol agents could partially remove Cd inhibition of DNA ligation, we speculate that part of the Cd inhibition of DNA repair may be through binding of Cd to the proteins participating in DNA ligation.
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Affiliation(s)
- S Lynn
- Institute of Zoology, Academia Sinica, Taipei, Republic of China
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Essers J, Hendriks RW, Swagemakers SM, Troelstra C, de Wit J, Bootsma D, Hoeijmakers JH, Kanaar R. Disruption of mouse RAD54 reduces ionizing radiation resistance and homologous recombination. Cell 1997; 89:195-204. [PMID: 9108475 DOI: 10.1016/s0092-8674(00)80199-3] [Citation(s) in RCA: 321] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Double-strand DNA break (DSB) repair by homologous recombination occurs through the RAD52 pathway in Saccharomyces cerevisiae. Its biological importance is underscored by the conservation of many RAD52 pathway genes, including RAD54, from fungi to humans. We have analyzed the phenotype of mouse RAD54-/- (mRAD54-/-) cells. Consistent with a DSB repair defect, these cells are sensitive to ionizing radiation, mitomycin C, and methyl methanesulfonate, but not to ultraviolet light. Gene targeting experiments demonstrate that homologous recombination in mRAD54-/- cells is reduced compared to wild-type cells. These results imply that, besides DNA end-joining mediated by DNA-dependent protein kinase, homologous recombination contributes to the repair of DSBs in mammalian cells. Furthermore, we show that mRAD54-/- mice are viable and exhibit apparently normal V(D)J and immunoglobulin class-switch recombination. Thus, mRAD54 is not required for the recombination processes that generate functional immunoglobulin and T cell receptor genes.
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Affiliation(s)
- J Essers
- Medical Genetics Center, Department of Cell Biology and Genetics, Erasmus University Rotterdam, The Netherlands
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31
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Kurosawa K, Asoh M, Akatsuka A, Matsuo T, Ochiai Y, Maekawa K. A Japanese patient with X-linked alpha-thalassemia/mental retardation syndrome: an additional case report. THE JAPANESE JOURNAL OF HUMAN GENETICS 1996; 41:329-32. [PMID: 8996969 DOI: 10.1007/bf01913176] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
X-linked alpha-thalassemia/mental retardation syndrome (ATR-X) is characterized by severe mental retardation, wide range of minor abnormalities, and association with an unusual form of alpha-thalassemia. Fifty patients in Caucasian origin have been reported. This is the second report of the syndrome demonstrated in Oriental patients.
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Affiliation(s)
- K Kurosawa
- Department of Pediatrics, Tokyo Metropolitan Kita Medical Rehabilitation Center for The Handicapped, Japan
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32
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Abstract
The expression of X-linked genes in females heterozygous for X-linked defects can be modulated by epigenetic control mechanisms that constitute the X chromosome inactivation pathway. At least four different effects have been found to influence, in females, the phenotypic expression of genes responsible for X-linked mental retardation (XLMR). First, non-random X inactivation, due either to stochastic or genetic factors, can result in tissues in which one cell type (for example, that in which the X chromosome carrying a mutant XLMR gene is active) dominates, instead of the normal mosaic cell population expected as a result of random X inactivation. Second, skewed inactivation of the normal X in individuals carrying a deletion of part of the X chromosome has been documented in a number of mentally retarded females. Third, functional disomy of X-linked genes that are expressed inappropriately due to the absence of X inactivation has been found in mentally retarded females with structurally abnormal X chromosomes that do not contain the X inactivation center. And fourth, dose-dependent overexpression of X-linked genes that normally "escape" X inactivation may account for the mental and developmental delay associated with increasing numbers of otherwise inactive X chromosomes in individuals with X chromosome aneuploidy.
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Affiliation(s)
- H F Willard
- Department of Genetics, Case Western Reserve University School of Medicine and University Hospitals of Cleveland, OH 44106, USA
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Villard L, Gecz J, Mattéi JF, Fontés M, Saugier-Veber P, Munnich A, Lyonnet S. XNP mutation in a large family with Juberg-Marsidi syndrome. Nat Genet 1996; 12:359-60. [PMID: 8630485 DOI: 10.1038/ng0496-359] [Citation(s) in RCA: 74] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
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Abstract
The chromosome-16 and the X-chromosome forms of alpha-thalassemia--ATR-16 and ATR-X--exemplify 2 important causes of syndromal mental retardation. ATR-16 is a contiguous gene syndrome which arises from loss of DNA from the tip of chromosome 16p13.3 by truncation, interstitial deletion, or unbalanced translocation. It provided the first example of a chromosome translocation that could be detected by molecular analysis but not conventional cytogenetics. It also provided the first example of a telomeric truncation giving rise to a complex genetic syndrome. In contrast ATR-X appears to be due to mutations in a trans-acting factor that regulates gene expression. Mutations in transcription factors have recently been identified in a number of genetic diseases (for example, Denys-Drash syndrome, WT1 [19]; pituitary dwarfism, PIT1 [16]; Rubinstein-Taybi syndrome, CBP [20]. Not only is this mechanism proving to be an important cause of complex syndromes but it is providing new perspectives on certain developmental pathways. XH2 may not be a classical transcription factor but it is certainly involved in the regulation of gene expression, exerting its effects on several different genes. It seems likely that other mutations in this class of regulatory proteins will be found in patients with complex disorders including mental retardation. In broader terms the 2 mechanisms described here may prove to be responsible for a significant proportion of mental retardation. However, without a feature such as alpha-thalassemia to pinpoint the area of genome or pathways involved it may prove difficult to identify other, similarly affected genes underlying other forms of mental retardation. As the human genome project and rapid genome analysis evolve this problem should become less of an obstacle. In the meantime, it is very worthwhile to continue looking for unusual clinical associations that may point to critical genes underlying human genetic disorders.
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Affiliation(s)
- R J Gibbons
- MRC Molecular Haematology Unit, Institute of Molecular Medicine, John Radcliffe Hospital, Headington, Oxford, UK
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Gibbons RJ, Picketts DJ, Villard L, Higgs DR. Mutations in a putative global transcriptional regulator cause X-linked mental retardation with alpha-thalassemia (ATR-X syndrome). Cell 1995; 80:837-45. [PMID: 7697714 DOI: 10.1016/0092-8674(95)90287-2] [Citation(s) in RCA: 416] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The ATR-X syndrome is an X-linked disorder comprising severe psychomotor retardation, characteristic facial features, genital abnormalities, and alpha-thalassemia. We have shown that ATR-X results from diverse mutations of XH2, a member of a subgroup of the helicase superfamily that includes proteins involved in a wide range of cellular functions, including DNA recombination and repair (RAD16, RAD54, and ERCC6) and regulation of transcription (SW12/SNF2, MOT1, and brahma). The complex ATR-X phenotype suggests that XH2, when mutated, down-regulates expression of several genes, including the alpha-globin genes, indicating that it could be a global transcriptional regulator. In addition to its role in the ATR-X syndrome, XH2 may be a good candidate for other forms of X-linked mental retardation mapping to Xq13.
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Affiliation(s)
- R J Gibbons
- Medical Research Council Molecular Haematology Unit, John Radcliffe Hospital, Headington, Oxford, England
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