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Cranston T, Boon H, Olesen MK, Ryan FJ, Shears D, London R, Rostom H, Elajnaf T, Thakker RV, Hannan FM. Spectrum of germline AIRE mutations causing APS-1 and familial hypoparathyroidism. Eur J Endocrinol 2022; 187:111-122. [PMID: 35521792 PMCID: PMC9175554 DOI: 10.1530/eje-21-0730] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/12/2021] [Accepted: 05/04/2022] [Indexed: 11/21/2022]
Abstract
Objective The autoimmune polyendocrine syndrome type 1 (APS-1) is an autosomal recessive disorder characterised by immune dysregulation and autoimmune endocrine gland destruction. APS-1 is caused by biallelic mutations affecting the autoimmune regulator (AIRE) gene on chromosome 21q22.3, which facilitates immunological self-tolerance. The objective was to investigate >300 probands with suspected APS-1 or isolated hypoparathyroidism for AIRE abnormalities. Methods Probands were assessed by DNA sequence analysis. Novel variants were characterised using 3D modelling of the AIRE protein. Restriction enzyme and microsatellite analysis were used to investigate for uniparental isodisomy. Results Biallelic AIRE mutations were identified in 35 probands with APS-1 and 5 probands with isolated hypoparathyroidism. These included a novel homozygous p.(His14Pro) mutation, predicted to disrupt the N-terminal caspase activation recruitment domain of the AIRE protein. Furthermore, an apparently homozygous AIRE mutation, p.Leu323fs, was identified in an APS-1 proband, who is the child of non-consanguineous asymptomatic parents. Microsatellite analysis revealed that the proband inherited two copies of the paternal mutant AIRE allele due to uniparental isodisomy. Hypoparathyroidism was the most common endocrine manifestation in AIRE mutation-positive probands and >45% of those harbouring AIRE mutations had at least two diseases out of the triad of candidiasis, hypoparathyroidism, and hypoadrenalism. In contrast, type 1 diabetes and hypothyroidism occurred more frequently in AIRE mutation-negative probands with suspected APS-1. Around 30% of AIRE mutation-negative probands with isolated hypoparathyroidism harboured mutations in other hypoparathyroid genes. Conclusions This study of a large cohort referred for AIRE mutational analysis expands the spectrum of genetic abnormalities causing APS-1.
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Affiliation(s)
- Treena Cranston
- Oxford Genetics Laboratories, Churchill Hospital, Oxford, UK
| | - Hannah Boon
- Oxford Genetics Laboratories, Churchill Hospital, Oxford, UK
| | - Mie K Olesen
- Academic Endocrine Unit, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Fiona J Ryan
- Paediatric Endocrinology, Children's Hospital, John Radcliffe Hospital, Oxford, UK
| | - Deborah Shears
- Oxford Centre for Genomic Medicine, Nuffield Orthopaedic Centre, Oxford, UK
| | - Rosemary London
- Paediatric Endocrinology, Children's Hospital, John Radcliffe Hospital, Oxford, UK
| | - Hussam Rostom
- Nuffield Department of Women's and Reproductive Health, University of Oxford, Oxford, UK
| | - Taha Elajnaf
- Nuffield Department of Women's and Reproductive Health, University of Oxford, Oxford, UK
| | - Rajesh V Thakker
- Academic Endocrine Unit, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
- National Institute for Health Research Oxford Biomedical Research Centre, Oxford, UK
| | - Fadil M Hannan
- Nuffield Department of Women's and Reproductive Health, University of Oxford, Oxford, UK
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2
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Perniola R, Fierabracci A, Falorni A. Autoimmune Addison's Disease as Part of the Autoimmune Polyglandular Syndrome Type 1: Historical Overview and Current Evidence. Front Immunol 2021; 12:606860. [PMID: 33717087 PMCID: PMC7953157 DOI: 10.3389/fimmu.2021.606860] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Accepted: 01/25/2021] [Indexed: 12/11/2022] Open
Abstract
The autoimmune polyglandular syndrome type 1 (APS1) is caused by pathogenic variants of the autoimmune regulator (AIRE) gene, located in the chromosomal region 21q22.3. The related protein, AIRE, enhances thymic self-representation and immune self-tolerance by localization to chromatin and anchorage to multimolecular complexes involved in the initiation and post-initiation events of tissue-specific antigen-encoding gene transcription. Once synthesized, the self-antigens are presented to, and cause deletion of, the self-reactive thymocyte clones. The clinical diagnosis of APS1 is based on the classic triad idiopathic hypoparathyroidism (HPT)—chronic mucocutaneous candidiasis—autoimmune Addison's disease (AAD), though new criteria based on early non-endocrine manifestations have been proposed. HPT is in most cases the first endocrine component of the syndrome; however, APS1-associated AAD has received the most accurate biochemical, clinical, and immunological characterization. Here is a comprehensive review of the studies on APS1-associated AAD from initial case reports to the most recent scientific findings.
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Affiliation(s)
- Roberto Perniola
- Department of Pediatrics-Neonatal Intensive Care, V. Fazzi Hospital, ASL LE, Lecce, Italy
| | - Alessandra Fierabracci
- Infectivology and Clinical Trials Research Department, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Alberto Falorni
- Section of Internal Medicine and Endocrinological and Metabolic Sciences, Department of Medicine, University of Perugia, Perugia, Italy
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Zheng WB, Li LJ, Zhao DC, Wang O, Jiang Y, Xia WB, Li M. A novel variant in AIRE causing a rare, non‑classical autoimmune polyendocrine syndrome type 1. Mol Med Rep 2020; 22:1285-1294. [PMID: 32627016 PMCID: PMC7339480 DOI: 10.3892/mmr.2020.11227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Accepted: 05/14/2020] [Indexed: 11/06/2022] Open
Abstract
Autoimmune polyendocrine syndrome type 1 (APS‑1) is a rare inherited autoimmune disease, characterized by a classic triad, including chronic mucocutaneous candidiasis, primary adrenocortical insufficiency and hypoparathyroidism. The present study investigated phenotypes and pathogenic variants in a Chinese woman with non‑classical APS‑1. Disease‑associated variants in a patient with APS‑1 were identified via targeted next generation sequencing and the variant was confirmed via Sanger sequencing. Serum levels of calcium, phosphorus, parathyroid hormone (PTH), follicle‑stimulating hormone (FSH), luteinizing hormone (LH), estradiol and urinary levels of calcium were measured. Blood count assays and bone marrow morphology were investigated. The patient was a 32‑year‑old woman who had suffered from typical carpopedal spasms since she was 7 years old. She developed syncope, primary amenorrhea, intermittent diarrhea and general fatigue in subsequent years. Hypocalcemia, hyperphosphatemia, low levels of PTH and estradiol, elevated levels of FSH and LH, and absence of erythroblasts were observed, which indicated hypoparathyroidism, primary ovarian insufficiency and pure red cell aplasia. A novel heterozygous missense variant (NM_000383.2: c.623G>T, NP_000374.1: p.Gly208Val) in exon 5 of autoimmune regulator and a reported variant (NM_000383.2: c.371C>T, NP_000374.1: p.Pro124Leu) in exon 3 were detected, of which the c.623G>T variant may be a pathogenic variation that induces APS‑1. Under a regular follow‑up and therapeutic adjustment of calcium, calcitriol, hormone replacement therapy and methylprednisolone, the endocrine function and clinical symptoms of the patient were notably improved. The results of the present study expand the known genetic and phenotypical spectra of APS‑1.
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Affiliation(s)
- Wen-Bin Zheng
- Department of Endocrinology, National Health Commission Key Laboratory of Endocrinology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, P.R. China
| | - Lu-Jiao Li
- Department of Endocrinology, National Health Commission Key Laboratory of Endocrinology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, P.R. China
| | - Di-Chen Zhao
- Department of Endocrinology, National Health Commission Key Laboratory of Endocrinology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, P.R. China
| | - Ou Wang
- Department of Endocrinology, National Health Commission Key Laboratory of Endocrinology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, P.R. China
| | - Yan Jiang
- Department of Endocrinology, National Health Commission Key Laboratory of Endocrinology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, P.R. China
| | - Wei-Bo Xia
- Department of Endocrinology, National Health Commission Key Laboratory of Endocrinology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, P.R. China
| | - Mei Li
- Department of Endocrinology, National Health Commission Key Laboratory of Endocrinology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, P.R. China
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4
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Pellegrino M, Bellacchio E, Dhamo R, Frasca F, Betterle C, Fierabracci A. A Novel Homozygous Mutation of the AIRE Gene in an APECED Patient From Pakistan: Case Report and Review of the Literature. Front Immunol 2018; 9:1835. [PMID: 30150985 PMCID: PMC6099424 DOI: 10.3389/fimmu.2018.01835] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Accepted: 07/25/2018] [Indexed: 11/13/2022] Open
Abstract
Autoimmune-poly-endocrinopathy-candidiasis-ectodermal-dystrophy syndrome (APECED) is a rare monogenic recessive disorder caused by mutations in the autoimmune regulator (AIRE) gene. Criteria for the diagnosis of APECED are the presence of two of the following disorders: chronic mucocutaneous candidiasis (CMC), chronic hypoparathyroidism (CHP), and Addison's disease. APECED develops at high incidence in Finns, Sardinians, and Iranian Jews and presents with a wide range of clinical phenotypes and genotypes. In this manuscript, we report the clinical, endocrinological, and molecular features of a 16-year-old female patient from Pakistan living in Italy and presenting the major APECED clinical manifestations CMC, CHP, and primary adrenal insufficiency. Premature ovarian failure, chronic bronchopneumopathy, vitiligo, Hashimoto's thyroiditis emerged as associated diseases. In our patient, AIRE gene screening revealed the novel c.396G>C (p.Arg132Ser; p.R132S) mutation in homozygosity thus confirming APECED diagnosis. This is the first reported mutation within the nuclear localization signal (NLS) that is associated with APECED. The NLS mutation affects the nuclear import of classical transcription factors through nuclear pore by recognition of nuclear import receptors, the importin α molecules. By displaying crystal structures of the peptide containing the KRK basic residue cluster bound to α importins, we show that p.R132S replacement in 131-KRK-133 does not reproduce these interactions. Thus, we propose that the novel mutation exerts its pathogenetic effect by impairing the nuclear import of the Aire protein. The present case report is added to a limited series of Pakistani APECED patients who we reviewed from the scientific literature, mostly diagnosed on clinical findings.
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Affiliation(s)
- Marsha Pellegrino
- Infectivology and Clinical Trials Research Division, Bambino Gesù Children’s Hospital, Rome, Italy
| | - Emanuele Bellacchio
- Molecular Genetics and Functional Genomics, Genetics and Rare Diseases Research Division, Bambino Gesù Children’s Hospital, Rome, Italy
| | | | - Federica Frasca
- Infectivology and Clinical Trials Research Division, Bambino Gesù Children’s Hospital, Rome, Italy
| | - Corrado Betterle
- Endocrine Unit, Department of Medicine (DIMED), University of Padua, Padua, Italy
| | - Alessandra Fierabracci
- Infectivology and Clinical Trials Research Division, Bambino Gesù Children’s Hospital, Rome, Italy
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5
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Speck-Hernandez CA, Assis AF, Felicio RF, Cotrim-Sousa L, Pezzi N, Lopes GS, Bombonato-Prado KF, Giuliatti S, Passos GA. Aire Disruption Influences the Medullary Thymic Epithelial Cell Transcriptome and Interaction With Thymocytes. Front Immunol 2018; 9:964. [PMID: 29867946 PMCID: PMC5949327 DOI: 10.3389/fimmu.2018.00964] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2017] [Accepted: 04/18/2018] [Indexed: 11/13/2022] Open
Abstract
The function of medullary thymic epithelial cells (mTECs) is associated with thymocyte adhesion, which is crucial for the negative selection of autoreactive thymocytes in the thymus. This process represents the root of central tolerance of self-components and prevents the onset of autoimmune diseases. Since thymic epithelia correspond to an important target of donor T cells during the onset of chronic graft-vs-host-disease, mTEC-thymocyte adhesion may have implications for alloimmunity. The Aire and Fezf2 genes function as transcriptome controllers in mTECs. The central question of this study is whether there is a mutual relationship between mTEC-thymocyte adhesion and the control of the mTEC transcriptome and whether Aire is involved in this process. Here, we show that in vitro mTEC-thymocyte adhesion causes transcriptome changes in mTECs and upregulates the transcriptional expression of Aire and Fezf2, as well as cell adhesion-related genes such as Cd80 or Tcf7, among others. Crispr-Cas9-mediated Aire gene disruption demonstrated that this gene plays a role in the process of mTEC-thymocyte adhesion. Consistent with the nuclear localization signal (NLS) encoded by Aire exon 3, which was targeted, we demonstrate that Aire KO-/- mTECs impair AIRE protein localization in the nucleus. Consequently, the loss of function of Aire reduced the ability of these cells to adhere to thymocytes. Their transcriptomes differed from their wild-type Aire+/+ counterparts, even during thymocyte adhesion. A set of mRNA isoforms that encode proteins involved in cell adhesion were also modulated during this process. This demonstrates that both thymocyte interactions and Aire influence transcriptome profiling of mTEC cells.
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Affiliation(s)
- Cesar A. Speck-Hernandez
- Graduate Programme in Basic and Applied Immunology, Universidade de São Paulo, São Paulo, Brazil
| | - Amanda F. Assis
- Molecular Immunogenetics Group, Genetics, Ribeirão Preto Medical School, Universidade de São Paulo, São Paulo, Brazil
| | - Rafaela F. Felicio
- Graduate Programme in Basic and Applied Immunology, Universidade de São Paulo, São Paulo, Brazil
| | - Larissa Cotrim-Sousa
- Molecular Immunogenetics Group, Genetics, Ribeirão Preto Medical School, Universidade de São Paulo, São Paulo, Brazil
| | - Nicole Pezzi
- Graduate Programme in Basic and Applied Immunology, Universidade de São Paulo, São Paulo, Brazil
| | - Gabriel S. Lopes
- Graduate Programme in Cellular and Molecular Biology, Ribeirão Preto Medical School, Universidade de São Paulo, São Paulo, Brazil
| | - Karina F. Bombonato-Prado
- Morphology, Physiology and Basic Pathology, School of Dentistry of Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil
| | - Silvana Giuliatti
- Genetics, Bioinformatics Group, Ribeirão Preto Medical School, Universidade de São Paulo, São Paulo, Brazil
| | - Geraldo A. Passos
- Molecular Immunogenetics Group, Genetics, Ribeirão Preto Medical School, Universidade de São Paulo, São Paulo, Brazil
- Morphology, Physiology and Basic Pathology, School of Dentistry of Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil
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6
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Abstract
About two decades ago, cloning of the autoimmune regulator (AIRE) gene materialized one of the most important actors on the scene of self-tolerance. Thymic transcription of genes encoding tissue-specific antigens (ts-ags) is activated by AIRE protein and embodies the essence of thymic self-representation. Pathogenic AIRE variants cause the autoimmune polyglandular syndrome type 1, which is a rare and complex disease that is gaining attention in research on autoimmunity. The animal models of disease, although not identically reproducing the human picture, supply fundamental information on mechanisms and extent of AIRE action: thanks to its multidomain structure, AIRE localizes to chromatin enclosing the target genes, binds to histones, and offers an anchorage to multimolecular complexes involved in initiation and post-initiation events of gene transcription. In addition, AIRE enhances mRNA diversity by favoring alternative mRNA splicing. Once synthesized, ts-ags are presented to, and cause deletion of the self-reactive thymocyte clones. However, AIRE function is not restricted to the activation of gene transcription. AIRE would control presentation and transfer of self-antigens for thymic cellular interplay: such mechanism is aimed at increasing the likelihood of engagement of the thymocytes that carry the corresponding T-cell receptors. Another fundamental role of AIRE in promoting self-tolerance is related to the development of thymocyte anergy, as thymic self-representation shapes at the same time the repertoire of regulatory T cells. Finally, AIRE seems to replicate its action in the secondary lymphoid organs, albeit the cell lineage detaining such property has not been fully characterized. Delineation of AIRE functions adds interesting data to the knowledge of the mechanisms of self-tolerance and introduces exciting perspectives of therapeutic interventions against the related diseases.
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Affiliation(s)
- Roberto Perniola
- Department of Pediatrics, Neonatal Intensive Care, Vito Fazzi Regional Hospital, Lecce, Italy
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7
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Passos GA, Speck‐Hernandez CA, Assis AF, Mendes‐da‐Cruz DA. Update on Aire and thymic negative selection. Immunology 2018; 153:10-20. [PMID: 28871661 PMCID: PMC5721245 DOI: 10.1111/imm.12831] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Revised: 08/24/2017] [Accepted: 08/31/2017] [Indexed: 12/17/2022] Open
Abstract
Twenty years ago, the autoimmune regulator (Aire) gene was associated with autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy, and was cloned and sequenced. Its importance goes beyond its abstract link with human autoimmune disease. Aire identification opened new perspectives to better understand the molecular basis of central tolerance and self-non-self distinction, the main properties of the immune system. Since 1997, a growing number of immunologists and molecular geneticists have made important discoveries about the function of Aire, which is essentially a pleiotropic gene. Aire is one of the functional markers in medullary thymic epithelial cells (mTECs), controlling their differentiation and expression of peripheral tissue antigens (PTAs), mTEC-thymocyte adhesion and the expression of microRNAs, among other functions. With Aire, the immunological tolerance became even more apparent from the molecular genetics point of view. Currently, mTECs represent the most unusual cells because they express almost the entire functional genome but still maintain their identity. Due to the enormous diversity of PTAs, this uncommon gene expression pattern was termed promiscuous gene expression, the interpretation of which is essentially immunological - i.e. it is related to self-representation in the thymus. Therefore, this knowledge is strongly linked to the negative selection of autoreactive thymocytes. In this update, we focus on the most relevant results of Aire as a transcriptional and post-transcriptional controller of PTAs in mTECs, its mechanism of action, and its influence on the negative selection of autoreactive thymocytes as the bases of the induction of central tolerance and prevention of autoimmune diseases.
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Affiliation(s)
- Geraldo A. Passos
- Molecular Immunogenetics GroupDepartment of GeneticsRibeirão Preto Medical SchoolUniversity of São PauloRibeirão PretoSPBrazil
- Discipline of Genetics and Molecular BiologyDepartment of Morphology, Physiology and Basic PathologySchool of Dentistry of Ribeirão PretoUniversity of São PauloRibeirão PretoSPBrazil
| | - Cesar A. Speck‐Hernandez
- Graduate Programme in Basic and Applied ImmunologyRibeirão Preto Medical SchoolUniversity of São PauloRibeirão PretoSPBrazil
| | - Amanda F. Assis
- Molecular Immunogenetics GroupDepartment of GeneticsRibeirão Preto Medical SchoolUniversity of São PauloRibeirão PretoSPBrazil
| | - Daniella A. Mendes‐da‐Cruz
- Laboratory on Thymus ResearchOswaldo Cruz InstituteOswaldo Cruz FoundationRio de JaneiroRJBrazil
- National Institute of Science and Technology on NeuroimmunomodulationRio de JaneiroRJBrazil
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8
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Abramson J, Goldfarb Y. AIRE: From promiscuous molecular partnerships to promiscuous gene expression. Eur J Immunol 2016; 46:22-33. [PMID: 26450177 DOI: 10.1002/eji.201545792] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2015] [Revised: 08/10/2015] [Accepted: 10/05/2015] [Indexed: 12/11/2022]
Abstract
Autoimmune regulator (AIRE) is a unique transcriptional regulator that induces promiscuous expression of thousands of tissue-restricted antigens (TRAs) in medullary thymic epithelial cells (mTECs), a step critical for the induction of immunological self-tolerance. The past 15 years have seen dramatic progress in our understanding of how AIRE induces immunological self-tolerance on a molecular level. This major advancement can be greatly attributed to the identification of a large variety of proteins that physically associate with AIRE, supporting and regulating its transcription-transactivation capacity. These diverse molecular partnerships have been shown to play roles in shuttling AIRE to the nucleus, securing AIRE's interaction with nuclear matrix and chromatin, releasing RNA polymerase-II from its stalled state and potentiating AIRE-mediated gene expression, among others. In this review we discuss the relationship of AIRE with its vast and rather diverse repertoire of partners and highlight how such "promiscuous partnerships" contribute to the phenomenon of "promiscuous gene expression" in the thymus.
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Affiliation(s)
- Jakub Abramson
- Department of Immunology, Weizmann Institute of Science, Rehovot, Israel
| | - Yael Goldfarb
- Department of Immunology, Weizmann Institute of Science, Rehovot, Israel
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9
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Maslovskaja J, Saare M, Liiv I, Rebane A, Peterson P. Extended HSR/CARD domain mediates AIRE binding to DNA. Biochem Biophys Res Commun 2015; 468:913-20. [PMID: 26607109 DOI: 10.1016/j.bbrc.2015.11.056] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2015] [Accepted: 11/12/2015] [Indexed: 02/06/2023]
Abstract
Autoimmune regulator (AIRE) activates the transcription of many genes in an unusual promiscuous and stochastic manner. The mechanism by which AIRE binds to the chromatin and DNA is not fully understood, and the regulatory elements that AIRE target genes possess are not delineated. In the current study, we demonstrate that AIRE activates the expression of transiently transfected luciferase reporters that lack defined promoter regions, as well as intron and poly(A) signal sequences. Our protein-DNA interaction experiments with mutated AIRE reveal that the intact homogeneously staining region/caspase recruitment domain (HSR/CARD) and amino acids R113 and K114 are key elements involved in AIRE binding to DNA.
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Affiliation(s)
- Julia Maslovskaja
- Molecular Pathology, Institute of Biomedicine and Translational Medicine, University of Tartu, Tartu, 50411, Estonia.
| | - Mario Saare
- Molecular Pathology, Institute of Biomedicine and Translational Medicine, University of Tartu, Tartu, 50411, Estonia
| | - Ingrid Liiv
- Molecular Pathology, Institute of Biomedicine and Translational Medicine, University of Tartu, Tartu, 50411, Estonia
| | - Ana Rebane
- Molecular Pathology, Institute of Biomedicine and Translational Medicine, University of Tartu, Tartu, 50411, Estonia
| | - Pärt Peterson
- Molecular Pathology, Institute of Biomedicine and Translational Medicine, University of Tartu, Tartu, 50411, Estonia
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Lopes N, Ferrier P, Irla M. [Induction of central tolerance by the factor Aire: molecular and epigenetic regulation]. Med Sci (Paris) 2015; 31:742-7. [PMID: 26340833 DOI: 10.1051/medsci/20153108012] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2023] Open
Abstract
The establishment of thymic central tolerance is a critical process to prevent the development of autoimmune diseases. Medullary thymic epithelial cells (mTEC) are essential to this process through the expression of the transcription factor Aire, which controls the transcription of many genes encoding tissue-restricted antigens. Mutations in the Aire gene are responsible for a rare autoimmune disorder called APECED (autoimmune polyendocrinopathy candidiasis ectodermal dystrophy). This review summarizes our current knowledge on the mode of action of Aire at the molecular and epigenetic levels in controlling the expression of tissue-restricted antigens. We also discuss recently described additional roles of this transcription factor in the induction of central T-cell tolerance.
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Affiliation(s)
- Noëlla Lopes
- Centre d'Immunologie de Marseille-Luminy, Aix Marseille Université UM2, Inserm, U1104, CNRS UMR7280, 13288 Marseille, France
| | - Pierre Ferrier
- Centre d'Immunologie de Marseille-Luminy, Aix Marseille Université UM2, Inserm, U1104, CNRS UMR7280, 13288 Marseille, France
| | - Magali Irla
- Centre d'Immunologie de Marseille-Luminy, Aix Marseille Université UM2, Inserm, U1104, CNRS UMR7280, 13288 Marseille, France
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Abstract
The human genome encodes seven isoforms of importin α which are grouped into three subfamilies known as α1, α2 and α3. All isoforms share a fundamentally conserved architecture that consists of an N-terminal, autoinhibitory, importin-β-binding (IBB) domain and a C-terminal Arm (Armadillo)-core that associates with nuclear localization signal (NLS) cargoes. Despite striking similarity in amino acid sequence and 3D structure, importin-α isoforms display remarkable substrate specificity in vivo. In the present review, we look at key differences among importin-α isoforms and provide a comprehensive inventory of known viral and cellular cargoes that have been shown to associate preferentially with specific isoforms. We illustrate how the diversification of the adaptor importin α into seven isoforms expands the dynamic range and regulatory control of nucleocytoplasmic transport, offering unexpected opportunities for pharmacological intervention. The emerging view of importin α is that of a key signalling molecule, with isoforms that confer preferential nuclear entry and spatiotemporal specificity on viral and cellular cargoes directly linked to human diseases.
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Incani F, Serra ML, Meloni A, Cossu C, Saba L, Cabras T, Messana I, Rosatelli MC. AIRE acetylation and deacetylation: effect on protein stability and transactivation activity. J Biomed Sci 2014; 21:85. [PMID: 25158603 PMCID: PMC4256887 DOI: 10.1186/s12929-014-0085-z] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2014] [Accepted: 08/16/2014] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND The AIRE protein plays a remarkable role as a regulator of central tolerance by controlling the promiscuous expression of tissue-specific antigens in thymic medullary epithelial cells. Defects in AIRE gene cause the autoimmune polyendocrinopathy- candidiasis-ectodermal dystrophy, a rare disease frequent in Iranian Jews, Finns, and Sardinian population. RESULTS In this study, we have precisely mapped, by mass spectrometry experiments, the sites of protein acetylation and, by mutagenesis assays, we have described a set of acetylated lysines as being crucial in influencing the subcellular localization of AIRE. Furthermore, we have also determined that the de-acetyltransferase enzymes HDAC1-2 are involved in the lysine de-acetylation of AIRE. CONCLUSIONS On the basis of our results and those reported in literature, we propose a model in which lysines acetylation increases the stability of AIRE in the nucleus. In addition, we observed that the interaction of AIRE with deacetylases complexes inhibits its transcriptional activity and is probably responsible for the instability of AIRE, which becomes more susceptible to degradation in the proteasome.
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Affiliation(s)
- Federica Incani
- />Dipartimento di Sanità Pubblica, Medicina Clinica e Molecolare, Unità di Ricerca di Scienze Biomediche e Biotecnologie, Università degli Studi di Cagliari, via Jenner s/n, Cagliari, Italy
| | - Maria Luisa Serra
- />Dipartimento di Sanità Pubblica, Medicina Clinica e Molecolare, Unità di Ricerca di Scienze Biomediche e Biotecnologie, Università degli Studi di Cagliari, via Jenner s/n, Cagliari, Italy
| | - Alessandra Meloni
- />Istituto di Ricerca Genetica e Biomedica, Consiglio Nazionale delle Ricerche, Cagliari, Italy
| | - Carla Cossu
- />Dipartimento di Sanità Pubblica, Medicina Clinica e Molecolare, Unità di Ricerca di Scienze Biomediche e Biotecnologie, Università degli Studi di Cagliari, via Jenner s/n, Cagliari, Italy
| | - Luisella Saba
- />Dipartimento di Sanità Pubblica, Medicina Clinica e Molecolare, Unità di Ricerca di Scienze Biomediche e Biotecnologie, Università degli Studi di Cagliari, via Jenner s/n, Cagliari, Italy
| | - Tiziana Cabras
- />Dipartimento di Scienze della Vita e dell’Ambiente, Sezione di Biochimica, Università degli Studi di Cagliari, Cagliari, Italy
| | - Irene Messana
- />Dipartimento di Scienze della Vita e dell’Ambiente, Sezione di Biochimica, Università degli Studi di Cagliari, Cagliari, Italy
| | - Maria Cristina Rosatelli
- />Dipartimento di Sanità Pubblica, Medicina Clinica e Molecolare, Unità di Ricerca di Scienze Biomediche e Biotecnologie, Università degli Studi di Cagliari, via Jenner s/n, Cagliari, Italy
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13
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Perniola R, Musco G. The biophysical and biochemical properties of the autoimmune regulator (AIRE) protein. BIOCHIMICA ET BIOPHYSICA ACTA 2014; 1842:326-37. [PMID: 24275490 DOI: 10.1016/j.bbadis.2013.11.020] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2013] [Revised: 11/11/2013] [Accepted: 11/18/2013] [Indexed: 01/20/2023]
Abstract
AIRE (for autoimmune regulator) is a multidomain protein that performs a fundamental function in the thymus and possibly in the secondary lymphoid organs: the regulation, especially in the sense of activation, of the process of gene transcription in cell lines deputed to the presentation of self-antigens to the maturing T lymphocytes. The apoptosis of the elements bearing T-cell receptors with critical affinity for the exhibited self-antigens prevents the escape of autoreactive clones and represents a simple and efficient mechanism of deletional self-tolerance. However, AIRE action relies on an articulated complex of biophysical and biochemical properties, in most cases attributable to single subspecialized domains. Here a thorough review of the matter is presented, with a privileged look at the pathogenic changes of AIRE that interfere with such properties and lead to the impairment in its chief function.
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Affiliation(s)
- Roberto Perniola
- Department of Pediatrics - Neonatal Intensive Care, V. Fazzi Regional Hospital, Piazza F. Muratore, I-73100, Lecce, Italy.
| | - Giovanna Musco
- Biomolecular NMR Laboratory, Center of Translational Genomics and Bioinformatics, Dulbecco Telethon Institute at San Raffaele Scientific Institute, Via Olgettina 58, I-20132, Milan, Italy.
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14
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Zumer K, Saksela K, Peterlin BM. The mechanism of tissue-restricted antigen gene expression by AIRE. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2013; 190:2479-82. [PMID: 23456700 DOI: 10.4049/jimmunol.1203210] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2023]
Abstract
The autoimmune regulator is a critical transcription factor for generating central tolerance in the thymus. Recent studies have revealed how the autoimmune regulator targets many otherwise tissue-restricted Ag genes to enable negative selection of autoreactive T cells.
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Affiliation(s)
- Kristina Zumer
- Department of Virology, Haartman Institute, Helsinki University Central Hospital, University of Helsinki, FIN-00014 Helsinki, Finland
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15
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Zhang J, Liu H, Liu Z, Liao Y, Guo L, Wang H, He L, Zhang X, Xing Q. A functional alternative splicing mutation in AIRE gene causes autoimmune polyendocrine syndrome type 1. PLoS One 2013; 8:e53981. [PMID: 23342054 PMCID: PMC3540864 DOI: 10.1371/journal.pone.0053981] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2012] [Accepted: 12/05/2012] [Indexed: 01/28/2023] Open
Abstract
Autoimmune polyendocrine syndrome type 1 (APS-1) is a rare autosomal recessive disease defined by the presence of two of the three conditions: mucocutaneous candidiasis, hypoparathyroidism, and Addison's disease. Loss-of-function mutations of the autoimmune regulator (AIRE) gene have been linked to APS-1. Here we report mutational analysis and functional characterization of an AIRE mutation in a consanguineous Chinese family with APS-1. All exons of the AIRE gene and adjacent exon-intron sequences were amplified by PCR and subsequently sequenced. We identified a homozygous missense AIRE mutation c.463G>A (p.Gly155Ser) in two siblings with different clinical features of APS-1. In silico splice-site prediction and minigene analysis were carried out to study the potential pathological consequence. Minigene splicing analysis and subsequent cDNA sequencing revealed that the AIRE mutation potentially compromised the recognition of the splice donor of intron 3, causing alternative pre-mRNA splicing by intron 3 retention. Furthermore, the aberrant AIRE transcript was identified in a heterozygous carrier of the c.463G>A mutation. The aberrant intron 3-retaining transcript generated a truncated protein (p.G155fsX203) containing the first 154 AIRE amino acids and followed by 48 aberrant amino acids. Therefore, our study represents the first functional characterization of the alternatively spliced AIRE mutation that may explain the pathogenetic role in APS-1.
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Affiliation(s)
- Junyu Zhang
- Children’s Hospital and Institutes of Biomedical Sciences, Fudan University, Shanghai, China
- Bio-X Institutes, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders (Ministry of Education), Shanghai Jiao Tong University, Shanghai, China
| | - Hongbin Liu
- Henan Provincial Corps Hospital, Chinese’s Armed Police Forces, Zhengzhou, China
| | - Zhiyuan Liu
- Henan Provincial Corps Hospital, Chinese’s Armed Police Forces, Zhengzhou, China
| | - Yong Liao
- Chongqing Municipal Corps Hospital, Chinese’s Armed Police Forces, Chongqing, China
| | - Luo Guo
- Children’s Hospital and Institutes of Biomedical Sciences, Fudan University, Shanghai, China
- Bio-X Institutes, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders (Ministry of Education), Shanghai Jiao Tong University, Shanghai, China
| | - Honglian Wang
- Children’s Hospital and Institutes of Biomedical Sciences, Fudan University, Shanghai, China
- Bio-X Institutes, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders (Ministry of Education), Shanghai Jiao Tong University, Shanghai, China
| | - Lin He
- Children’s Hospital and Institutes of Biomedical Sciences, Fudan University, Shanghai, China
- Bio-X Institutes, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders (Ministry of Education), Shanghai Jiao Tong University, Shanghai, China
| | - Xiaodong Zhang
- Neuroscience & Behavioral Disorders Program, Duke-NUS Graduate Medical School Singapore, Singapore
- Department of Physiology, National University of Singapore, Singapore
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, United States of America
| | - Qinghe Xing
- Children’s Hospital and Institutes of Biomedical Sciences, Fudan University, Shanghai, China
- Bio-X Institutes, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders (Ministry of Education), Shanghai Jiao Tong University, Shanghai, China
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16
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Vasicova P, Stradalova V, Halada P, Hasek J, Malcova I. Nuclear import of chromatin remodeler Isw1 is mediated by atypical bipartite cNLS and classical import pathway. Traffic 2012; 14:176-93. [PMID: 23121014 DOI: 10.1111/tra.12025] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2012] [Revised: 10/29/2012] [Accepted: 11/01/2012] [Indexed: 11/28/2022]
Abstract
The protein Isw1 of Saccharomyces cerevisiae is an imitation-switch chromatin-remodeling factor. We studied the mechanisms of its nuclear import and found that the nuclear localization signal (NLS) mediating the transport of Isw1 into the nucleus is located at the end of the C-terminus of the protein (aa1079-1105). We show that it is an atypical bipartite signal with an unconventional linker of 19 aa (KRIR X(19) KKAK) and the only nuclear targeting signal within the Isw1 molecule. The efficiency of Isw1 nuclear import was found to be modulated by changes to the amino acid composition in the vicinity of the KRIR motif, but not by the linker length. Live-cell imaging of various karyopherin mutants and in vitro binding assays of Isw1NLS to importin-α revealed that the nuclear translocation of Isw1 is mediated by the classical import pathway. Analogous motifs to Isw1NLS are highly conserved in Isw1 homologues of other yeast species, and putative bipartite cNLS were identified in silico at the end of the C-termini of imitation switch (ISWI) proteins from higher eukaryotes. We suggest that the C-termini of the ISWI family proteins play an important role in their nuclear import.
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Affiliation(s)
- Pavla Vasicova
- Laboratory of Cell Reproduction, Institute of Microbiology v.v.i., Academy of Sciences of the Czech Republic, Videnska 1083, Cz-14220, Prague 4, Czech Republic
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17
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Saare M, Rebane A, Rajashekar B, Vilo J, Peterson P. Autoimmune regulator is acetylated by transcription coactivator CBP/p300. Exp Cell Res 2012; 318:1767-78. [PMID: 22659170 DOI: 10.1016/j.yexcr.2012.04.013] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2012] [Revised: 04/12/2012] [Accepted: 04/17/2012] [Indexed: 11/17/2022]
Abstract
The Autoimmune Regulator (AIRE) is a regulator of transcription in the thymic medulla, where it controls the expression of a large set of peripheral-tissue specific genes. AIRE interacts with the transcriptional coactivator and acetyltransferase CBP and synergistically cooperates with it in transcriptional activation. Here, we aimed to study a possible role of AIRE acetylation in the modulation of its activity. We found that AIRE is acetylated in tissue culture cells and this acetylation is enhanced by overexpression of CBP and the CBP paralog p300. The acetylated lysines were located within nuclear localization signal and SAND domain. AIRE with mutations that mimicked acetylated K243 and K253 in the SAND domain had reduced transactivation activity and accumulated into fewer and larger nuclear bodies, whereas mutations that mimicked the unacetylated lysines were functionally similar to wild-type AIRE. Analogously to CBP, p300 localized to AIRE-containing nuclear bodies, however, the overexpression of p300 did not enhance the transcriptional activation of AIRE-regulated genes. Further studies showed that overexpression of p300 stabilized the AIRE protein. Interestingly, gene expression profiling revealed that AIRE, with mutations mimicking K243/K253 acetylation in SAND, was able to activate gene expression, although the affected genes were different and the activation level was lower from those regulated by wild-type AIRE. Our results suggest that the AIRE acetylation can influence the selection of AIRE activated genes.
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Affiliation(s)
- Mario Saare
- Molecular Pathology, Institute of General and Molecular Pathology, University of Tartu, 19th Ravila Str, Tartu, Estonia.
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18
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Lovewell T, Tazi-Ahnini R. Models to explore the molecular function and regulation of AIRE. EGYPTIAN JOURNAL OF MEDICAL HUMAN GENETICS 2011. [DOI: 10.1016/j.ejmhg.2011.06.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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19
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Lott K, Bhardwaj A, Sims PJ, Cingolani G. A minimal nuclear localization signal (NLS) in human phospholipid scramblase 4 that binds only the minor NLS-binding site of importin alpha1. J Biol Chem 2011; 286:28160-9. [PMID: 21690087 PMCID: PMC3151061 DOI: 10.1074/jbc.m111.228007] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2011] [Revised: 06/10/2011] [Indexed: 12/16/2022] Open
Abstract
Importin α1 can bind classical nuclear localization signals (NLSs) in two NLS-binding sites, known as "major" and "minor." The major site is located between ARM repeats 2-4, whereas the minor site spans ARM 7-8. In this study, we have characterized the cellular localization of human phospholipid scramblase 4 (hPLSCR4), a member of the phospholipid scramblase protein family. We identified a minimal NLS in hPLSCR4 ((273)GSIIRKWN(280)) that contains only two basic amino acids. This NLS is both necessary for nuclear localization of hPLSCR4 in transfected HeLa cells and sufficient for nuclear import of a non-diffusible cargo in permeabilized cells. Mutation of only one of the two basic residues, Arg(277), correlates with loss of nuclear localization, suggesting this amino acid plays a key role in nuclear transport. Crystallographic analysis of mammalian importin α1 in complex with the hPLSCR4-NLS reveals this minimal NLS binds specifically and exclusively to the minor binding site of importin α. These data provide the first structural and functional evidence of a novel NLS-binding mode in importin α1 that uses only the minor groove as the exclusive site for nuclear import of nonclassical cargos.
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Affiliation(s)
- Kaylen Lott
- From the Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107
- the Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, New York 13210, and
| | - Anshul Bhardwaj
- From the Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107
| | - Peter J. Sims
- the Department of Pathology and Laboratory Medicine, University of Rochester Medical Center, Rochester, New York 14642-8626
| | - Gino Cingolani
- From the Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107
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20
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Perdomo J, Fock EL, Kaur G, Yan F, Khachigian LM, Jans DA, Chong BH. A monopartite sequence is essential for p45 NF-E2 nuclear translocation, transcriptional activity and platelet production. J Thromb Haemost 2010; 8:2542-53. [PMID: 20854373 DOI: 10.1111/j.1538-7836.2010.04058.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
BACKGROUND p45 NF-E2 is a bZIP transcription factor crucial for thrombopoiesis, as indicated by the fact that loss of p45 NF-E2 function results in dramatic embryonic lethal thrombopoietic defects and its overexpression boosts platelet release. OBJECTIVES In the present study, we set out to identify the sequences responsible for p45 NF-E2 nuclear import, evaluate its transport mechanism and ascertain its functional significance. METHODS A series of p45 NF-E2 deletion constructs fused to green fluorescent protein (GFP) was created and their cellular localization examined in mammalian cells, with the factor responsible for nuclear import identified using an in vitro transport assay. A p45 NF-E2 derivative mutated in the nuclear targeting sequence (NLS) was generated and its biological activity compared with wild type (wt) in luciferase assays, and proplatelet and platelet production measured in murine megakaryocytes transduced with a retroviral vector. RESULTS Here we show that residues 271-273 are essential for nuclear import of p45 NF-E2 in COS-7 and in primary bone marrow cells. The p45 NF-E2 NLS facilitates nuclear import specifically via importin (IMP) 7. Although within the DNA-binding domain of p45 NF-E2, the NLS is not essential for DNA-binding, but is crucial for transcriptional activation and biological activity; where, in contrast to wt, a mutant derivative with a mutated NLS failed to promote proplatelet and platelet production in murine megakaryocytes. CONCLUSIONS The NLS is critical for p45 NF-E2 function, with the present study being the first to demonstrate the importance of NLS-dependent nuclear import of p45 NF-E2 for platelet development.
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Affiliation(s)
- J Perdomo
- Centre for Vascular Research, University of New South Wales, Sydney, New South Wales, Australia
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21
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Meloni A, Fiorillo E, Corda D, Incani F, Serra ML, Contini A, Cao A, Rosatelli MC. DAXX is a new AIRE-interacting protein. J Biol Chem 2010; 285:13012-21. [PMID: 20185822 PMCID: PMC2857146 DOI: 10.1074/jbc.m109.037747] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2009] [Revised: 02/09/2010] [Indexed: 01/18/2023] Open
Abstract
The AIRE protein plays a remarkable role as a regulator of central tolerance by controlling the promiscuous expression of tissue-specific antigens in thymic medullary epithelial cells. Defects in the AIRE gene cause the autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy, a rare disease frequent in Iranian Jews, Finns, and Sardinian population. To this day, the precise function of the AIRE protein in regulating transcription and its interacting proteins has yet to be entirely clarified. The knowledge of novel AIRE interactors and their precise role will improve our knowledge of its biological activity and address some of the foremost autoimmunity-related questions. In this study, we have used a yeast two-hybrid system to identify AIRE-interacting proteins. This approach led us to the discovery of a new AIRE-interacting protein called DAXX. The protein is known to be a multifunctional adaptor with functions both in apoptosis and in transcription regulation pathways. The interaction between AIRE and DAXX has been validated by in vivo coimmunoprecipitation analysis and colocalization study in mammalian cells. The interaction has been further confirmed by showing in transactivation assays that DAXX exerts a strong repressive role on the transcriptional activity of AIRE.
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Affiliation(s)
- Allesandra Meloni
- From the
Istituto di Neurogenetica e Neurofarmacologia, Consiglio Nazionale delle Ricerche and
| | - Edoardo Fiorillo
- the
Dipartimento di Scienze Biomediche e Biotecnologie, Università degli Studi di Cagliari, 09121 Cagliari, Italy
| | - Denise Corda
- the
Dipartimento di Scienze Biomediche e Biotecnologie, Università degli Studi di Cagliari, 09121 Cagliari, Italy
| | - Federica Incani
- the
Dipartimento di Scienze Biomediche e Biotecnologie, Università degli Studi di Cagliari, 09121 Cagliari, Italy
| | - Maria Luisa Serra
- the
Dipartimento di Scienze Biomediche e Biotecnologie, Università degli Studi di Cagliari, 09121 Cagliari, Italy
| | - Antonella Contini
- the
Dipartimento di Scienze Biomediche e Biotecnologie, Università degli Studi di Cagliari, 09121 Cagliari, Italy
| | - Antonio Cao
- From the
Istituto di Neurogenetica e Neurofarmacologia, Consiglio Nazionale delle Ricerche and
| | - Maria Cristina Rosatelli
- the
Dipartimento di Scienze Biomediche e Biotecnologie, Università degli Studi di Cagliari, 09121 Cagliari, Italy
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22
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Abstract
A pool of immature T cells with a seemingly unrestricted repertoire of antigen specificities is generated life-long in the thymus. Amongst these cells are, however, thymocytes that express a strongly self-reactive antigen receptor and hence hold the potential to trigger autoimmunity. To prevent such an outcome, the thymus employs several independent but functionally related strategies that act in parallel to enforce self-tolerance. The deletion of strongly self-reactive thymocytes and the generation of regulatory T cells constitute the two most efficient mechanisms to induce and maintain immunological tolerance. Thymic epithelial cells of the medulla express for this purpose tissue-restricted self-antigens. This review will focus on the cellular and molecular mechanisms operative in the thymus to shape a repertoire of mature T cells tolerant to self-antigens.
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Affiliation(s)
- G A Holländer
- Department of Clinical-Biological Sciences, Laboratory of Pediatric Immunology, Center for Biomedicine, University of Basel and The University Children's Hospital, Switzerland.
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23
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Peterson P, Org T, Rebane A. Transcriptional regulation by AIRE: molecular mechanisms of central tolerance. Nat Rev Immunol 2008; 8:948-57. [PMID: 19008896 PMCID: PMC2785478 DOI: 10.1038/nri2450] [Citation(s) in RCA: 172] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The negative selection of T cells in the thymus is necessary for the maintenance of self tolerance. Medullary thymic epithelial cells have a key function in this process as they express a large number of tissue-specific self antigens that are presented to developing T cells. Mutations in the autoimmune regulator (AIRE) protein cause a breakdown of central tolerance that is associated with decreased expression of self antigens in the thymus. In this Review, we discuss the role of AIRE in the thymus and recent advances in our understanding of how AIRE might function at the molecular level to regulate gene expression.
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Affiliation(s)
- Pärt Peterson
- Institute of General and Molecular Pathology, University of Tartu, Tartu 5O411, Estonia.
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24
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Saltis M, Criscitiello MF, Ohta Y, Keefe M, Trede NS, Goitsuka R, Flajnik MF. Evolutionarily conserved and divergent regions of the autoimmune regulator (Aire) gene: a comparative analysis. Immunogenetics 2008; 60:105-14. [PMID: 18214467 PMCID: PMC7039057 DOI: 10.1007/s00251-007-0268-9] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2007] [Accepted: 12/05/2007] [Indexed: 01/06/2023]
Abstract
During T cell differentiation, medullary thymic epithelial cells (MTEC) expose developing T cells to tissue-specific antigens. MTEC expression of such self-antigens requires the transcription factor autoimmune regulator (Aire). In mammals, defects in aire result in multi-tissue, T cell-mediated autoimmunity. Because the T cell receptor repertoire is randomly generated and extremely diverse in all jawed vertebrates, it is likely that an aire-dependent T cell tolerance mechanism also exists in nonmammalian vertebrates. We have isolated aire genes from animals in all gnathostome classes except the cartilaginous fish by a combination of molecular techniques and scanning of expressed sequence tags and genomic databases. The deduced amino acid sequences of Aire were compared among mouse, human, opossum, chicken, Xenopus, zebrafish, and pufferfish. The first of two plant homeodomains (PHD) in human Aire and regions associated with nuclear and cytoplasmic localization are evolutionarily conserved, while other domains are either absent or divergent in one or more vertebrate classes. Furthermore, the second zinc-binding domain previously named Aire PHD2 appears to have greater sequence similarity with Ring finger domains than to PHD domains. Point mutations in defective human aire genes are generally found in the most evolutionarily conserved regions of the protein. These findings reveal a very rapid evolution of certain regions of aire during vertebrate evolution and support the existence of an aire-dependent mechanism of T cell tolerance dating back at least to the emergence of bony fish.
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Affiliation(s)
- Mark Saltis
- Department of Microbiology and Immunology, University of Maryland, Baltimore, MD 21201, USA
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25
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DeVoss JJ, Anderson MS. Lessons on immune tolerance from the monogenic disease APS1. Curr Opin Genet Dev 2007; 17:193-200. [PMID: 17466510 DOI: 10.1016/j.gde.2007.04.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2007] [Accepted: 04/13/2007] [Indexed: 12/28/2022]
Abstract
Autoimmunity is a complex disease process that results from a breakdown in the ability of the immune system to discriminate self from non-self. One approach to unraveling how autoimmunity occurs is to study monogenic diseases, for which a single gene defect is responsible. Recent work on the monogenic autoimmune disease 'autoimmune polyglandular syndrome type 1' (APS1) and on the causal gene of this disorder--autoimmune regulator (AIRE)--is providing new lessons on how immune tolerance is maintained.
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Affiliation(s)
- Jason J DeVoss
- University of California San Francisco Diabetes Center, HSW1102, San Francisco, CA 94143-0540, USA.
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