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Abstract
Severe combined immune deficiencies (SCIDs) are a group of monogenic diseases resulting in profound disturbances of lymphocyte development and function. Affected individuals are prone to life-threatening infections and without treatment do not survive beyond the first year of life. Haematopoietic stem cell transplantation from a well-matched donor offers high rates of survival, but in the absence of a suitable matched donor, parental haploidentical transplants are associated with greater complications, lower success rates and in some instances poor long-term immune recovery. Alternative therapeutic options based on correction of the defective gene by retroviral gene delivery have been used to correct X-linked SCID (SCID-X1) and adenosine deaminase-deficient SCID (ADA-SCID). A number of clinical trials have established that ex vivo gene transfer into haematopoietic progenitor cells allows effective recovery of immune defects and that gene therapy can offer a successful alternative to transplantation. The development of leukaemia as a result of insertional mutagenesis in one trial of gene therapy for SCID-X1 has raised concerns regarding the toxicity of retroviral vector-based gene delivery. These side effects are now being studied in detail and measures to prevent such events through alternative vectors delivery systems are in development at present.
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Affiliation(s)
- H Bobby Gaspar
- Institute of Child Health, 30 Guilford Street, London, WC1N 1EH, UK.
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202
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Zhang Y, Zhou J, Cao X, Zhang Q, Lim CUK, Ullrich RL, Bailey SM, Liber HL. Partial deficiency of DNA-PKcs increases ionizing radiation-induced mutagenesis and telomere instability in human cells. Cancer Lett 2006; 250:63-73. [PMID: 17095151 DOI: 10.1016/j.canlet.2006.09.021] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2006] [Revised: 09/14/2006] [Accepted: 09/22/2006] [Indexed: 12/21/2022]
Abstract
The correct repair of DNA double-strand breaks (DSBs) is essential to maintaining the integrity of the genome. Misrepair of DSBs is detrimental to cells and organisms, leading to gene mutation, chromosomal aberration, and cancer development. Nonhomologous end-joining (NHEJ) is one of the principal rejoining processes in most higher eukaryotic cells. NHEJ is facilitated by DNA-dependent protein kinase (DNA-PK), which is composed of a catalytic subunit, DNA-PKcs, and the heterodimeric DNA binding regulatory complex Ku70/86. Null mutation of DNA-PKcs leads to immunodeficiency, chromosomal aberration, gene mutation, telomeric end-capping failure, and cancer predisposition in animals and cells. However, it is unknown whether partial deficiency of DNA-PKcs as might occur in a fraction of the population (e.g., heterozygotes), influences cellular function. Using small interfering RNA (siRNA) transfection, we established partial deficiency of DNA-PKcs in human cells, ranging from 4 to 85% of control levels. Our results reveal for the first time, that partial deficiency of DNA-PKcs leads to increased ionizing radiation (IR)-induced mutagenesis, cell killing, and telomere dysfunction. Radiation mutagenesis was increased inversely with DNA-PKcs protein level, with the most pronounced effect being observed in cells with protein levels below 50% of controls. A small but statistically significant increase in IR-induced cell killing was observed as DNA-PKcs levels decreased, over the entire range of protein levels. Frequencies of IR-induced telomere-DSB fusion was increased at levels of DNA-PKcs as low as approximately 50%, similar to what would be expected in heterozygous individuals. Taken together, our results suggest that even partial deficiency of DNA repair proteins may represent a considerable risk to genomic stability.
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Affiliation(s)
- Ying Zhang
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO 80521, USA.
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203
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Seymour R, Sundberg JP, Hogenesch H. Abnormal lymphoid organ development in immunodeficient mutant mice. Vet Pathol 2006; 43:401-23. [PMID: 16846982 DOI: 10.1354/vp.43-4-401] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Development of the primary and secondary lymphoid organs is a tightly controlled process. These tissues are highly organized to maximize efficiency of the immune response. Spontaneous and targeted mutations in laboratory mice have led to better understanding of the molecular interactions and signaling pathways essential to the development and organization of lymphoid tissues, and the functional consequences of loss or disruption of the normal structures. On the basis of studies of mutations in mice and other species, it has been determined that a wild-type allele of the Foxn1 gene is required for normal thymic development and function. The Tlx1, Bapx1, Tcf21, Wt1 and Dh genes are essential for development of the spleen, while mutations of Nkx2-3, Lta, Ltb, Ltbr, Map3k14, Relb, Tnf, Tnfrsf1a, Cxcl13, Blr1 (Cxcr5), or cpdm genes result in disruption of normal splenic microarchitecture. The requirements for organized lymph nodes vary according to anatomic location, but most rely on Id2 (Idb2) and Rorc, in addition to lymphotoxins and Tnfrsf11a, Tnfsf11, Relb, Map3k14, Cxcl13, and Blr1 genes. Development of Peyer's patches is dependent on Id2 and Rorc genes, lymphotoxins, and Relb, Map3k14, Il7r, and cpdm genes. Less is known about the requirements for nasal-associated lymphoid tissues (NALT), but Id2 is a requirement. Here we review abnormalities of lymphoid organ development in immunodeficient mutant mice, including spontaneous and targeted mutations of Id2, Rorc, Tnf, Tnfrsf1a, Lta, Ltb, Ltbr, Tnfrsf11a, Tnfsf11, Relb, Map3k14, IL7r, Blr1, and Cxcl13 genes.
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Affiliation(s)
- R Seymour
- Department of Veterinary Pathobiology, Purdue University, Veterinary Pathology Building, 725 Harrison Street, West Lafayette, IN 47907-2027 (USA)
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204
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Zheng X, Schwarz K. Making V(D)J rearrangement visible: quantification of recombination efficiency in real time at the single cell level. J Immunol Methods 2006; 315:133-43. [PMID: 16935293 DOI: 10.1016/j.jim.2006.07.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2006] [Revised: 07/10/2006] [Accepted: 07/20/2006] [Indexed: 11/27/2022]
Abstract
V(D)J recombination is of fundamental importance for the diversity of immunoglobulin and T cell receptor genes. An enhanced green fluorescent protein (EGFP) based assay was successfully developed to monitor V(D)J recombination efficiency. This assay makes V(D)J recombination visible at the single cell level in real time. Surprisingly, despite a high (60% to 90%) transfection efficiency, the EGFP based V(D)J recombination efficiency was found to be low ( approximately 1%) in 293 cells. The EGFP based V(D)J recombination efficiency correlated well with that achieved by the classical V(D)J recombination assay. The EGFP based V(D)J recombination efficiency depended on the relative RAG (recombination activating gene)-1 and RAG-2 but not Artemis expression vector concentrations used for co-transfection. A rise of RAG-1 dosage increased recombination efficiency. In contrast, a surplus of RAG-2 inhibited V(D)J recombination efficiency. The test differentiates RAG null mutants as seen in human severe combined immunodeficiency (SCID).
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Affiliation(s)
- Xiao Zheng
- Department of Transfusion Medicine, University Hospital Ulm, Institute for Clinical Transfusion Medicine and Immunogenetics, German Red Cross Blood Service Baden-Württemberg-Hessen, Institute Ulm, Helmholtzstrasse 10, D-89081 Ulm, Germany
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205
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Abstract
Knowledge of the genetic mutations of primary immune deficiency syndromes has grown significantly over the last 30 years. In this article the authors present an overview of the clinical aspects, laboratory evaluation, and genetic defects of primary immunodeficiencies, with an emphasis on the pathophysiology of the known molecular defects. This article is designed to give the primary pediatrician a general knowledge of this rapidly expanding field.
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Affiliation(s)
- James W Verbsky
- Division of Rheumatology, Department of Pediatrics, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA
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206
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Broides A, Ault BH, Arthus MF, Bichet DG, Conley ME. Severe combined immunodeficiency associated with nephrogenic diabetes insipidus and a deletion in the Xq28 region. Clin Immunol 2006; 120:147-55. [PMID: 16781893 DOI: 10.1016/j.clim.2006.05.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2005] [Revised: 04/28/2006] [Accepted: 05/01/2006] [Indexed: 11/21/2022]
Abstract
We evaluated a baby boy with severe combined immunodeficiency (SCID) and X-linked nephrogenic diabetes insipidus (NDI). This patient had less than 10% CD3+ T cells, almost all of which were positive for CD4 and CD45RO. Genetic studies demonstrated a 34.4 kb deletion at Xq28 which included AVPR2, the gene responsible for NDI; ARHGAP4, a hematopoietic specific gene encoding a GTPase-activating protein; and a highly conserved segment of DNA between ARHGAP4 and ARD1A, a gene involved in the response to hypoxia. Other patients with NDI, but without immunodeficiency, have had deletions that remove all ARHGAP4 except exon 1; however, no other patients have had deletions of the highly conserved intragenic region between ARHGAP4 and ARD1A. X chromosome inactivation studies, done on sorted cells from the mother and grandmother of the patient, carriers of the deletion, demonstrated exclusive use of the non-mutant X chromosome as the active X in CD4 and CD8 T cells. Surprisingly, NK cells, monocytes and neutrophils from these women demonstrated preferential use of the mutant X chromosome as the active X. These results are consistent with an X-linked form of SCID, due to the loss of regulatory elements that control the response to hypoxia in hematopoietic cells.
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Affiliation(s)
- Arnon Broides
- Department of Immunology, University of Tennessee College of Medicine, St. Jude Children's Research Hospital, 332 North Lauderdale, Memphis, TN 38105, USA.
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207
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Abstract
The origin of the recombination-activating genes (RAGs) is considered to be a foundation hallmark for adaptive immunity, characterised by the presence of antigen receptor genes that provide the ability to recognise and respond to specific peptide antigens. In vertebrates, a diverse repertoire of antigen-specific receptors, T cell receptors and immunoglobulins is generated by V(D)J recombination performed by the RAG-1 and RAG-2 protein complex. RAG homologues were identified in many jawed vertebrates. Despite their crucial importance, no homologues have been found in jawless vertebrates and invertebrates. This paper focuses on the RAG homologues in humans and other vertebrates for which the genome is completely sequenced, and also discusses the main contribution of the use of RAG homologues in phylogenetics and vertebrate evolution. Since mutations in both genes cause a spectrum of severe combined immunodeficiencies, including the Omenn syndrome (OS), these topics are discussed in detail. Finally, the relevance to genomic diversity and implications to immunomics are addressed. The search for homologues could enlighten us about the evolutionary processes that shaped the adaptive immune system. Understanding the diversity of the adaptive immune system is crucially important for the design and development of new therapies to modulate the immune responses in humans and/or animal models.
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Affiliation(s)
- Maristela Martins de Camargo
- Department of Immunology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP 05508-900, Brazil
| | - Laila Alves Nahum
- Department of Biological Science, Louisiana State University, Baton Rouge, LA 70803, USA
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208
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Hönig M, Schwarz K. Omenn syndrome: a lack of tolerance on the background of deficient lymphocyte development and maturation. Curr Opin Rheumatol 2006; 18:383-8. [PMID: 16763459 DOI: 10.1097/01.bor.0000231907.50290.6f] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE OF REVIEW Omenn syndrome is a rare inherited primary immunodeficiency characterized by severe combined immunodeficiency in combination with autoimmune features leading to squamous erythrodermia, alopecia, lymphadenopathy, hepatosplenomegaly, and intractable diarrhea. Recent advances include characterizing the genetic basis of the syndrome and integrating the genetic defects into knowledge of tolerance induction. RECENT FINDINGS Molecular studies have shown that besides the well-known hypomorphic recombination activating gene defects, mutations in the nonhomologous end-joining factor Artemis and in the interleukin-7 receptor alpha chain can contribute to the development of Omenn syndrome. These investigations established that Omenn syndrome is a genetically heterogeneous condition. Whereas the majority of patients with Omenn syndrome bear hypomorphic gene alterations, some exhibit somatic mosaicism due to second-site reversions of null alleles. A lack of central tolerance contributes to the autoimmune pathology of the disease. SUMMARY Research has begun to clarify the genetic defects and the conditions underlying the lack of tolerance enforcement that predispose to Omenn syndrome. Clinical applications of this research include the identification of the causative genetic defect in the majority of Omenn syndrome cases and the use of this genetic knowledge in family and prenatal analyses and in difficult differential autoimmune diagnoses.
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Affiliation(s)
- Manfred Hönig
- Institute for Clinical Transfusion Medicine and Immunogenetics, Department of Transfusion Medicine, Germany
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209
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Enders A, Fisch P, Schwarz K, Duffner U, Pannicke U, Nikolopoulos E, Peters A, Orlowska-Volk M, Schindler D, Friedrich W, Selle B, Niemeyer C, Ehl S. A Severe Form of Human Combined Immunodeficiency Due to Mutations in DNA Ligase IV. THE JOURNAL OF IMMUNOLOGY 2006; 176:5060-8. [PMID: 16585603 DOI: 10.4049/jimmunol.176.8.5060] [Citation(s) in RCA: 110] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
DNA ligase IV (LigIV) deficiency was identified as the molecular basis for a severe form of combined immunodeficiency in two microcephalic siblings with cellular radiosensitivity. In one patient the diagnosis was made directly after birth, allowing analysis of the role of LigIV in the development of specific immune cells. Absolute numbers of B cells were reduced 100-fold and alphabeta T cells 10-fold, whereas gammadelta T cells were normal. Spectratyping of all three cell populations showed a diverse repertoire, but sequencing of IgH V(D)J junctions revealed shorter CDR3 regions due to more extensive nucleotide deletions among D and J elements and fewer N nucleotide insertions. Clonal restriction of IgG-expressing, but not IgM-expressing, B cells and the lack of primary and secondary lymph node follicles indicated impaired class switch recombination. Observations in the older sibling showed that this rudimentary immune system was able to mount specific responses to infection. However, partial Ab responses and extensive amplification of gammadelta T cells could not prevent a life-threatening course of viral and bacterial infections, the development of an EBV-induced lymphoma, and immune dysregulation reflected by severe autoimmune cytopenia. Impaired generation of immune diversity under conditions of limited LigIV activity can cause a human SCID variant with a characteristic immunological phenotype.
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Affiliation(s)
- Anselm Enders
- Department of Pediatrics and Adolescent Medicine, University of Freiburg, Freiburg, Germany
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210
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Abstract
The genes that encode immunoglobulin and T cell receptor proteins are assembled from component gene segments in a reaction known as V(D)J recombination. The reaction, and its crucial mediators RAG1 and RAG2, are essential for lymphocyte development and hence for adaptive immunity. Here we consider the biochemistry of this reaction, focusing on the DNA transactions and the proteins involved. We discuss how the RAG proteins interact with DNA and how coordinate cleavage of the DNA at two sites might be achieved. Finally, we consider the RAG proteins and V(D)J recombination from an evolutionary point of view.
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Affiliation(s)
- D G Schatz
- Section of Immunobiology, Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, CT 06520-8011, USA.
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211
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Faber C, Morbach H, Singh SK, Girschick HJ. Differential expression patterns of recombination-activating genes in individual mature B cells in juvenile idiopathic arthritis. Ann Rheum Dis 2006; 65:1351-6. [PMID: 16504994 PMCID: PMC1798333 DOI: 10.1136/ard.2005.047878] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
BACKGROUND Re-expression of the recombination-activating genes (RAG) in peripheral B cells may be relevant in the development of autoreactive antibodies in autoimmune diseases. The presence of antinuclear antibodies (ANA) as a hallmark of oligoarticular juvenile idiopathic arthritis (o-JIA, early-onset type) indicates a breakdown in immunological tolerance. AIM To examine the expression of RAG genes in peripheral blood mature B lymphocytes in patients with o-JIA. METHODS 777 memory B cells from peripheral blood, CD19+ CD27+ CD5+ or CD19+ CD27+ CD5-, isolated from three ANA+ children with o-JIA and three healthy age-matched children, were examined for the expression of RAG1 and RAG2 mRNA. mRNA transcripts of activation-induced cytidine deaminase and immunoglobulin G were searched to further determine their developmental stage. RESULTS mRNA was present for any of the two RAG genes in the B cells of children with JIA and controls. However, the predominance of RAG1 or RAG2 was different. A significantly decreased frequency of RAG2-expressing memory B cells in both CD5+ and CD5- populations was noted in children with JIA (p<0.001), whereas the number of RAG1-expressing B cells was slightly increased. The coordinate expression of both the RAG genes was a rare event, similar in the CD5+ populations (1% in controls, 2% in children with JIA), but different among the CD5- compartments (5% v 0%; p<0.01). CONCLUSION These results argue for a reduced coordinate RAG expression in the peripheral CD5- memory B cells of patients with o-JIA. Thus, it was hypothesised that impaired receptor revision contributes to autoimmune pathogenesis in JIA.
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Affiliation(s)
- C Faber
- Section of Paediatric Rheumatology and Osteology, Children's Hospital, University of Würzburg, Josef Schneider Str 2, D-97080 Würzburg, Germany
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212
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Buck D, Moshous D, de Chasseval R, Ma Y, le Deist F, Cavazzana-Calvo M, Fischer A, Casanova JL, Lieber MR, de Villartay JP. Severe combined immunodeficiency and microcephaly in siblings with hypomorphic mutations in DNA ligase IV. Eur J Immunol 2006; 36:224-35. [PMID: 16358361 DOI: 10.1002/eji.200535401] [Citation(s) in RCA: 163] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
DNA double-strand breaks (dsb) during V(D)J recombination of T and B lymphocyte receptor genes are resolved by the non-homologous DNA end joining pathway (NHEJ) including at least six factors: Ku70, Ku80, DNA-PK(cs), Artemis, Xrcc4, and DNA ligase IV (Lig4). Artemis and Lig4 are the only known V(D)J/NHEJ factors found deficient in human genetic disorders. Null mutations of the Artemis gene result in a complete absence of T and B lymphocytes and increased cellular sensitivity to ionizing radiations, causing radiosensitive-SCID. Mutations of Lig4 are exclusively hypomorphic and have only been described in six patients, four exhibiting mild immunodeficiency associated with microcephaly and developmental delay, while two patient had leukemia. Here we report a SCID associated with microcephaly caused by compound heterozygous hypomorphic mutations in Lig4. Residual activity of Lig4 in these patients is underscored by a normal pattern of TCR-alpha and -beta junctions in the T cells of the patients and a moderate impairment of V(D)J recombination as tested in vitro. These observations contrast with the severity of the clinical immunodeficiency, suggesting that Lig4 may have additional critical roles in lymphocyte survival beyond V(D)J recombination.
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Affiliation(s)
- Dietke Buck
- INSERM, Hôpital Necker Enfants-Malades, U429, Unité Développement Normal et Pathologique du Système Immunitaire, Paris, France
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213
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de Villartay JP, Lim A, Al-Mousa H, Dupont S, Déchanet-Merville J, Coumau-Gatbois E, Gougeon ML, Lemainque A, Eidenschenk C, Jouanguy E, Abel L, Casanova JL, Fischer A, Le Deist F. A novel immunodeficiency associated with hypomorphic RAG1 mutations and CMV infection. J Clin Invest 2006; 115:3291-9. [PMID: 16276422 PMCID: PMC1265866 DOI: 10.1172/jci25178] [Citation(s) in RCA: 157] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2005] [Accepted: 08/23/2005] [Indexed: 11/17/2022] Open
Abstract
Amorphic mutations in the recombination activating genes RAG1 and RAG2 have been reported to cause T- B- SCID, whereas hypomorphic mutations led to the expansion of a few autoimmune T cell clones responsible for the Omenn syndrome phenotype. We report here a novel clinical and immunological phenotype associated with recessive RAG1 hypomorphic mutations in 4 patients from 4 different families. The immunological phenotype consists of the oligoclonal expansion of TCR gammadelta T cells combined with TCR alphabeta T cell lymphopenia. The clinical phenotype consists of severe, disseminated CMV infection and autoimmune blood cell manifestations. Repertoire studies suggest that CMV infection, in the setting of this particular T cell immunodeficiency, may have driven the TCR gammadelta T cell clonal expansion. This observation extends the range of clinical and immunological phenotypes associated with RAG mutations, emphasizing the role of the genetic background and microbial environment in determining disease phenotype.
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214
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Dudley DD, Chaudhuri J, Bassing CH, Alt FW. Mechanism and control of V(D)J recombination versus class switch recombination: similarities and differences. Adv Immunol 2006; 86:43-112. [PMID: 15705419 DOI: 10.1016/s0065-2776(04)86002-4] [Citation(s) in RCA: 214] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
V(D)J recombination is the process by which the variable region exons encoding the antigen recognition sites of receptors expressed on B and T lymphocytes are generated during early development via somatic assembly of component gene segments. In response to antigen, somatic hypermutation (SHM) and class switch recombination (CSR) induce further modifications of immunoglobulin genes in B cells. CSR changes the IgH constant region for an alternate set that confers distinct antibody effector functions. SHM introduces mutations, at a high rate, into variable region exons, ultimately allowing affinity maturation. All of these genomic alteration processes require tight regulatory control mechanisms, both to ensure development of a normal immune system and to prevent potentially oncogenic processes, such as translocations, caused by errors in the recombination/mutation processes. In this regard, transcription of substrate sequences plays a significant role in target specificity, and transcription is mechanistically coupled to CSR and SHM. However, there are many mechanistic differences in these reactions. V(D)J recombination proceeds via precise DNA cleavage initiated by the RAG proteins at short conserved signal sequences, whereas CSR and SHM are initiated over large target regions via activation-induced cytidine deaminase (AID)-mediated DNA deamination of transcribed target DNA. Yet, new evidence suggests that AID cofactors may help provide an additional layer of specificity for both SHM and CSR. Whereas repair of RAG-induced double-strand breaks (DSBs) involves the general nonhomologous end-joining DNA repair pathway, and CSR also depends on at least some of these factors, CSR requires induction of certain general DSB response factors, whereas V(D)J recombination does not. In this review, we compare and contrast V(D)J recombination and CSR, with particular emphasis on the role of the initiating enzymes and DNA repair proteins in these processes.
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Affiliation(s)
- Darryll D Dudley
- Howard Hughes Medical Institute, The Children's Hospital Boston, CBR Institute for Biomedical Research, and Harvard Medical School, Boston, MA 02115, USA
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215
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Pathways of DNA Double-Strand Break Repair in Mammalian Cells after Ionizing Radiation. Genome Integr 2006. [DOI: 10.1007/7050_011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
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216
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Abstract
Mammals contend with a universe of evolving pathogens by generating an enormous diversity of antigen receptors during lymphocyte development. Precursor B and T cells assemble functional immunoglobulin (Ig) and T cell receptor (TCR) genes via recombination of numerous variable (V), diversity (D), and joining (J) gene segments. Although this combinatorial process generates significant diversity, genetic reorganization is inherently dangerous. Thus, V(D)J recombination must be tightly regulated to ensure proper lymphocyte development and avoid chromosomal translocations that cause lymphoid tumors. Each genomic rearrangement is mediated by a common V(D)J recombinase that recognizes sequences flanking all antigen receptor gene segments. The specificity of V(D)J recombination is due, in large part, to changes in the accessibility of chromatin at target gene segments, which either permits or restricts access to recombinase. The chromatin configuration of antigen receptor loci is governed by the concerted action of enhancers and promoters, which function as accessibility control elements (ACEs). In general, ACEs act as conduits for transcription factors, which in turn recruit enzymes that covalently modify or remodel nucleosomes. These ACE-mediated alterations are critical for activation of gene segment transcription and for opening chromatin associated with recombinase target sequences. In this chapter, we describe advances in understanding the mechanisms that control V(D)J recombination at the level of chromatin accessibility. The discussion will focus on cis-acting regulation by ACEs, the nuclear factors that control ACE function, and the epigenetic modifications that establish recombinase accessibility.
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Affiliation(s)
- Robin Milley Cobb
- Department of Microbiology and Immunology, Vanderbilt University, Nashville, Tennessee, USA
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217
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Abstract
Far from being mutually exclusive, immunodeficiency and autoimmunity may occur simultaneously. During the last years, analysis of Autoimmune Polyendocrinopathy--Candidiasis--Ectodermal Dystrophy (APECED) and Immunodysregulation--Polyendocrinopathy--Enteropathy--X-linked (IPEX), two rare monogenic forms of immunodeficiency associated with autoimmunity, has led to the identification of Auto Immune Regulator (AIRE) and Forkhead Box P3 (FOXP3), essential transcriptional regulators, involved in central tolerance and peripheral immune homeostasis, respectively. Characterization of the molecular and cellular mechanisms involved in APECED, and recognition that AIRE expression is sustained by effective thymopoiesis, has recently allowed to define that the autoimmunity of Omenn syndrome, a combined immunodeficiency due to defects of V(D)J recombination, also results from defective expression of AIRE. The implications of identification of the basis of autoimmunity in these rare forms of immunodeficiency have important implications for a better understanding of more common autoimmune disorders, and for development of novel therapeutic approaches.
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Affiliation(s)
- Luigi D Notarangelo
- Angelo Nocivelli Institute for Molecular Medicine, Department of Pediatrics, University of Brescia, Brescia, Italy
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218
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Lagresle-Peyrou C, Yates F, Malassis-Séris M, Hue C, Morillon E, Garrigue A, Liu A, Hajdari P, Stockholm D, Danos O, Lemercier B, Gougeon ML, Rieux-Laucat F, de Villartay JP, Fischer A, Cavazzana-Calvo M. Long-term immune reconstitution in RAG-1-deficient mice treated by retroviral gene therapy: a balance between efficiency and toxicity. Blood 2005; 107:63-72. [PMID: 16174758 DOI: 10.1182/blood-2005-05-2032] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Severe combined immunodeficiency (SCID) caused by mutations in RAG1 or RAG2 genes is characterized by a complete block in T- and B-cell development. The only curative treatment is allogeneic hematopoietic stem cell transplantation, which gives a high survival rate (90%) when an HLA-genoidentical donor exists but unsatisfactory results when only partially compatible donors are available. We have thus been interested in the development of a potential alternative treatment by using retroviral gene transfer of a normal copy of RAG1 cDNA. We show here that this approach applied to RAG-1-deficient mice restores normal B- and T-cell function even in the presence of a reduced number of mature B cells. The reconstitution is stable over time, attesting to a selective advantage of transduced progenitors. Notably, a high transgene copy number was detected in all lymphoid organs, and this was associated with a risk of lymphoproliferation as observed in one mouse. Altogether, these results demonstrate that correction of RAG-1 deficiency can be achieved by gene therapy in immunodeficient mice but that human application would require the use of self-inactivated vector to decrease the risk of lymphoproliferative diseases.
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Affiliation(s)
- Chantal Lagresle-Peyrou
- Université Paris-Descartes, Faculté de médecine, Inserm Unit 429, site Necker-Enfants Malades, 149 rue de Sèvres, 75743 Paris Cedex15, France.
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219
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van der Burg M, van Veelen LR, Verkaik NS, Wiegant WW, Hartwig NG, Barendregt BH, Brugmans L, Raams A, Jaspers NGJ, Zdzienicka MZ, van Dongen JJM, van Gent DC. A new type of radiosensitive T-B-NK+ severe combined immunodeficiency caused by a LIG4 mutation. J Clin Invest 2005; 116:137-45. [PMID: 16357942 PMCID: PMC1312018 DOI: 10.1172/jci26121] [Citation(s) in RCA: 149] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2005] [Accepted: 10/18/2005] [Indexed: 12/30/2022] Open
Abstract
V(D)J recombination of Ig and TCR loci is a stepwise process during which site-specific DNA double-strand breaks (DSBs) are made by RAG1/RAG2, followed by DSB repair by nonhomologous end joining. Defects in V(D)J recombination result in SCID characterized by absence of mature B and T cells. A subset of T-B-NK+ SCID patients is sensitive to ionizing radiation, and the majority of these patients have mutations in Artemis. We present a patient with a new type of radiosensitive T-B-NK+ SCID with a defect in DNA ligase IV (LIG4). To date, LIG4 mutations have only been described in a radiosensitive leukemia patient and in 4 patients with a designated LIG4 syndrome, which is associated with chromosomal instability, pancytopenia, and developmental and growth delay. The patient described here shows that a LIG4 mutation can also cause T-B-NK+ SCID without developmental defects. The LIG4-deficient SCID patient had an incomplete but severe block in precursor B cell differentiation, resulting in extremely low levels of blood B cells. The residual D(H)-J(H) junctions showed extensive nucleotide deletions, apparently caused by prolonged exonuclease activity during the delayed D(H)-J(H) ligation process. In conclusion, different LIG4 mutations can result in either a developmental defect with minor immunological abnormalities or a SCID picture with normal development.
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Affiliation(s)
- Mirjam van der Burg
- Department of Immunology and Department of Cell Biology and Genetics, Erasmus Medical Center, Rotterdam, The Netherlands
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220
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Battista S, Fedele M, Hoyos J, Pentimalli F, Pierantoni G, Visone R, De Martino I, Croce C, Fusco A. High-mobility-group A1 (HMGA1) proteins down-regulate the expression of the recombination activating gene 2 (RAG2). Biochem J 2005; 389:91-7. [PMID: 15713121 PMCID: PMC1184541 DOI: 10.1042/bj20041607] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
HMGA1 (high-mobility-group A1) proteins are architectural transcription factors that are found overexpressed in embryogenesis and malignant tumours. We have shown previously that they have a role in lymphopoiesis, since the loss of HMGA1 expression leads to an impairment of T-cell development and to an increase in B-cell population. Since RAGs (recombination activating genes) are key regulators of lymphoid differentiation, in the present study we investigate whether RAG2 expression is dependent on HMGA1 activity. We show that RAG2 gene expression is up-regulated in Hmga1-/- ES (embryonic stem) cells and EBs (embryoid bodies) as well as in yolk sacs and fibroblasts from Hmga1-/- mice, suggesting that HMGA1 proteins control RAG2 gene expression both in vitro and in vivo. We show that the effect of HMGA1 on RAG2 expression is direct, identify the responsible region in the RAG2 promoter and demonstrate binding to the promoter in vivo using chromatin immunoprecipitation. Since RAG2 is necessary for lymphoid cell development, our results suggest a novel mechanism by which HMGA1 might regulate lymphoid differentiation.
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Affiliation(s)
- Sabrina Battista
- *Dipartimento di Biologia e Patologia Cellulare e Molecolare e/o Istituto di Endocrinologia ed Oncologia Sperimentale del CNR, Facoltà di Medicina e Chirurgia di Napoli, Università degli Studi di Napoli ‘Federico II’, via Pansini, 5, 80131 Naples, Italy
| | - Monica Fedele
- *Dipartimento di Biologia e Patologia Cellulare e Molecolare e/o Istituto di Endocrinologia ed Oncologia Sperimentale del CNR, Facoltà di Medicina e Chirurgia di Napoli, Università degli Studi di Napoli ‘Federico II’, via Pansini, 5, 80131 Naples, Italy
| | - Josefina Martinez Hoyos
- *Dipartimento di Biologia e Patologia Cellulare e Molecolare e/o Istituto di Endocrinologia ed Oncologia Sperimentale del CNR, Facoltà di Medicina e Chirurgia di Napoli, Università degli Studi di Napoli ‘Federico II’, via Pansini, 5, 80131 Naples, Italy
| | - Francesca Pentimalli
- *Dipartimento di Biologia e Patologia Cellulare e Molecolare e/o Istituto di Endocrinologia ed Oncologia Sperimentale del CNR, Facoltà di Medicina e Chirurgia di Napoli, Università degli Studi di Napoli ‘Federico II’, via Pansini, 5, 80131 Naples, Italy
| | - Giovanna Maria Pierantoni
- *Dipartimento di Biologia e Patologia Cellulare e Molecolare e/o Istituto di Endocrinologia ed Oncologia Sperimentale del CNR, Facoltà di Medicina e Chirurgia di Napoli, Università degli Studi di Napoli ‘Federico II’, via Pansini, 5, 80131 Naples, Italy
| | - Rosa Visone
- *Dipartimento di Biologia e Patologia Cellulare e Molecolare e/o Istituto di Endocrinologia ed Oncologia Sperimentale del CNR, Facoltà di Medicina e Chirurgia di Napoli, Università degli Studi di Napoli ‘Federico II’, via Pansini, 5, 80131 Naples, Italy
| | - Ivana De Martino
- *Dipartimento di Biologia e Patologia Cellulare e Molecolare e/o Istituto di Endocrinologia ed Oncologia Sperimentale del CNR, Facoltà di Medicina e Chirurgia di Napoli, Università degli Studi di Napoli ‘Federico II’, via Pansini, 5, 80131 Naples, Italy
| | - Carlo Maria Croce
- †Kimmel Cancer Center, Thomas Jefferson University, 233 S 10th Street, Philadelphia, PA 19107, U.S.A
| | - Alfredo Fusco
- *Dipartimento di Biologia e Patologia Cellulare e Molecolare e/o Istituto di Endocrinologia ed Oncologia Sperimentale del CNR, Facoltà di Medicina e Chirurgia di Napoli, Università degli Studi di Napoli ‘Federico II’, via Pansini, 5, 80131 Naples, Italy
- ‡NOGEC (Naples Oncogenomic Center)–CEINGE, Biotecnologie Avanzate, via Comunale Margherita 482, 80145, Naples, Italy
- To whom correspondence should be addressed, at Dipartimento di Biologia e Patologia Cellulare e Molecolare (email )
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221
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Cunningham-Rundles C, Ponda PP. Molecular defects in T- and B-cell primary immunodeficiency diseases. Nat Rev Immunol 2005; 5:880-92. [PMID: 16261175 DOI: 10.1038/nri1713] [Citation(s) in RCA: 118] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
More than 120 inherited primary immunodeficiency diseases have been discovered in the past five decades, and the precise genetic defect in many of these diseases has now been identified. Increasing understanding of these molecular defects has considerably influenced both basic and translational research, and this has extended to many branches of medicine. Recent advances in both diagnosis and therapeutic modalities have allowed these defects to be identified earlier and to be more precisely defined, and they have also resulted in more promising long-term outcomes. The prospect of gene therapy continues to be included in the armamentarium of treatment considerations, because these conditions could be among the first to benefit from gene-therapy trials in humans.
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Affiliation(s)
- Charlotte Cunningham-Rundles
- Division of Clinical Immunology, Mount Sinai School of Medicine, 1425 Madison Avenue, Box 1089, New York, New York 10029, USA.
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222
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Buckley RH. Variable phenotypic expression of mutations in genes of the immune system. J Clin Invest 2005; 115:2974-6. [PMID: 16276411 PMCID: PMC1265883 DOI: 10.1172/jci26956] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Discovery of mutated genes that cause various types of primary immunodeficiencies has significantly advanced our understanding of the pathogenesis of these diseases and of the functions of normal gene products. However, it is becoming abundantly clear that the phenotypic presentation of mutations in a given gene can be quite different, depending upon the location and type of mutation but also probably upon other genetic factors and environmental influences. In this issue of the JCI, de Villartay et al. describe a third phenotype for mutations in recombination activating gene 1 (RAG1), in addition to the already known phenotypes of SCID and Omenn syndrome (see the related article beginning on page 3291).
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Affiliation(s)
- Rebecca H Buckley
- Department of Pediatrics, Duke University Medical Center, Durham, North Carolina 27710, USA.
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223
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Ehl S, Schwarz K, Enders A, Duffner U, Pannicke U, Kühr J, Mascart F, Schmitt-Graeff A, Niemeyer C, Fisch P. A variant of SCID with specific immune responses and predominance of gamma delta T cells. J Clin Invest 2005; 115:3140-8. [PMID: 16211094 PMCID: PMC1242191 DOI: 10.1172/jci25221] [Citation(s) in RCA: 128] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2005] [Accepted: 07/19/2005] [Indexed: 01/24/2023] Open
Abstract
We describe here a patient with a clinical and molecular diagnosis of recombinase activating gene 1-deficient (RAG1-deficient) SCID, who produced specific antibodies despite minimal B cell numbers. Memory B cells were detected and antibodies were produced not only against some vaccines and infections, but also against autoantigens. The patient had severely reduced levels of oligoclonal T cells expressing the alphabeta TCR but surprisingly normal numbers of T cells expressing the gammadelta TCR. Analysis at a clonal level and TCR complementarity-determining region-3 spectratyping for gammadelta T cells revealed a diversified oligoclonal repertoire with predominance of cells expressing a gamma4-delta3 TCR. Several gammadelta T cell clones displayed reactivity against CMV-infected cells. These observations are compatible with 2 non-mutually exclusive explanations for the gammadelta T cell predominance: a developmental advantage and infection-triggered, antigen-driven peripheral expansion. The patient carried the homozygous hypomorphic R561H RAG1 mutation leading to reduced V(D)J recombination but lacked all clinical features characteristic of Omenn syndrome. This report describes a new phenotype of RAG deficiency and shows that the ability to form specific antibodies does not exclude the diagnosis of SCID.
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MESH Headings
- Amino Acid Sequence
- Base Sequence
- Cells, Cultured
- Clone Cells
- Cytomegalovirus/immunology
- Cytomegalovirus Infections/immunology
- Female
- Fibroblasts/immunology
- Fibroblasts/virology
- Homeodomain Proteins/genetics
- Humans
- Immunophenotyping
- Infant
- Molecular Sequence Data
- Receptors, Antigen, T-Cell, gamma-delta/analysis
- Receptors, Antigen, T-Cell, gamma-delta/biosynthesis
- Receptors, Antigen, T-Cell, gamma-delta/genetics
- Severe Combined Immunodeficiency/genetics
- Severe Combined Immunodeficiency/immunology
- T-Lymphocytes/immunology
- T-Lymphocytes/metabolism
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Affiliation(s)
- Stephan Ehl
- Department of Pediatrics and Adolescent Medicine, University of Freiburg, Freiburg, Germany.
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224
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Weiler CR, Bankers-Fulbright JL. Common variable immunodeficiency: test indications and interpretations. Mayo Clin Proc 2005; 80:1187-200. [PMID: 16178499 DOI: 10.4065/80.9.1187] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Common variable immunodeficiency (CVID) is a primary immunodeficiency disorder that can present with multiple phenotypes, all of which are characterized by hypogammaglobulinemia, in a person at any age. A specific genetic defect that accounts for all CVID phenotypes has not been identified, and it is likely that several distinct genetic disorders with similar clinical presentations are responsible for the observed variation. In this review, we summarize the known genetic mutations that give rise to hypogammaglobulinemia and how these gene products affect normal or abnormal B-cell development and function, with particular emphasis on CVID. Additionally, we describe specific phenotypic and genetic laboratory tests that can be used to diagnose CVID and provide guidelines for test interpretation and subsequent therapeutic intervention.
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Affiliation(s)
- Catherine R Weiler
- Department of Internal Medicine and Division of Allergic Diseases, Mayo Clinic College of Medicine, Rochester, MN 55905, USA
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225
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Zhang J, Quintal L, Atkinson A, Williams B, Grunebaum E, Roifman CM. Novel RAG1 mutation in a case of severe combined immunodeficiency. Pediatrics 2005; 116:e445-9. [PMID: 16061569 DOI: 10.1542/peds.2005-0369] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
OBJECTIVE The recombination activating enzymes RAG1 and RAG2 are essential to the process of V(D)J rearrangement in B and T cells and thus to the development of normal immune function. Mutations in RAG1 or RAG2 can lead to a spectrum of disorders, ranging from typical (B-)(T-) severe combined immunodeficiency to Omenn's syndrome. We present a unique presentation of RAG1 deficiency. PATIENT We report on a 6-month-old girl who presented with severe respiratory distress, which continued to progress despite antibiotic therapy but seemed to respond to treatment with corticosteroids. The patient exhibited no erythroderma or eosinophilia, and her lymphoid organs were not enlarged. RESULTS Investigation of the immune system showed normal numbers of CD3+ T cells, which expressed either CD4 or CD8. Subsequent analysis of the T-cell receptor demonstrated that nearly all CD3+ T cells were clonal; one clone expressed CD4, whereas the other expressed CD8. The extremely restricted T-cell repertoire and the lack of circulating B cells prompted analysis of the RAG1 gene, which revealed a novel homozygous thymine to cytosine substitution at nucleotide position 2686. CONCLUSIONS This case underscores the importance of more extensive evaluation of the immune system even when widely available, standard, flow cytometric analysis shows normal numbers of T cells that express CD4 or CD8, especially in the absence of circulating B cells.
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Affiliation(s)
- Junyan Zhang
- Division of Immunology and Allergy, Hospital for Sick Children, University of Toronto, Toronto, Canada
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226
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Elkin SK, Ivanov D, Ewalt M, Ferguson CG, Hyberts SG, Sun ZYJ, Prestwich GD, Yuan J, Wagner G, Oettinger MA, Gozani OP. A PHD finger motif in the C terminus of RAG2 modulates recombination activity. J Biol Chem 2005; 280:28701-10. [PMID: 15964836 DOI: 10.1074/jbc.m504731200] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The RAG1 and RAG2 proteins catalyze V(D)J recombination and are essential for generation of the diverse repertoire of antigen receptor genes and effective immune responses. RAG2 is composed of a "core" domain that is required for the recombination reaction and a C-terminal nonessential or "non-core" region. Recent evidence has emerged arguing that the non-core region plays a critical regulatory role in the recombination reaction, and mutations in this region have been identified in patients with immunodeficiencies. Here we present the first structural data for the RAG2 protein, using NMR spectroscopy to demonstrate that the C terminus of RAG2 contains a noncanonical PHD finger. All of the non-core mutations of RAG2 that are implicated in the development of immunodeficiencies are located within the PHD finger, at either zinc-coordinating residues or residues adjacent to an alpha-helix on the surface of the domain that participates in binding to the signaling molecules, phosphoinositides. Functional analysis of disease and phosphoinositide-binding mutations reveals novel intramolecular interactions within the non-core region and suggests that the PHD finger adopts two distinct states. We propose a model in which the equilibrium between these states modulates recombination activity. Together, these data identify the PHD finger as a novel and functionally important domain of RAG2.
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Affiliation(s)
- Sheryl K Elkin
- Department of Molecular Biology, Massachusetts General Hospital, Boston, Massachusetts 02114, USA
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227
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Fischer A, Le Deist F, Hacein-Bey-Abina S, André-Schmutz I, Basile GDS, de Villartay JP, Cavazzana-Calvo M. Severe combined immunodeficiency. A model disease for molecular immunology and therapy. Immunol Rev 2005; 203:98-109. [PMID: 15661024 DOI: 10.1111/j.0105-2896.2005.00223.x] [Citation(s) in RCA: 179] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Severe combined immunodeficiencies (SCIDs) consist of genetically determined arrest of T-cell differentiation. Ten different molecular defects have now been identified, which all lead to early death in the absence of therapy. Transplantation of allogeneic hematopoietic stem cells (HSCT) can restore T-cell development, thus saving the lives of SCID patients. In this review, the different characteristics of HSCT are discussed along with the available data regarding the long-term outcome. Transient thymopoiesis caused by an exhaustion of donor progenitor cells and possibly a progressive loss of thymus function can lead to a progressive decline in T-cell functions. The preliminary results of gene therapy show the correction of two SCID conditions. Based on the assumption that long-lasting pluripotent progenitor cells are transduced, these data suggest that gene therapy could overcome the long-term recurrence of the T-cell immunodeficiency. SCID is thus a disease model for experimental therapy in the hematopoietic system.
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Affiliation(s)
- Alain Fischer
- INSERM U429, Hôpital Necker-Enfants Malades, Paris, France.
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228
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Wang J, Pluth JM, Cooper PK, Cowan MJ, Chen DJ, Yannone SM. Artemis deficiency confers a DNA double-strand break repair defect and Artemis phosphorylation status is altered by DNA damage and cell cycle progression. DNA Repair (Amst) 2005; 4:556-70. [PMID: 15811628 DOI: 10.1016/j.dnarep.2005.02.001] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2004] [Accepted: 01/04/2005] [Indexed: 11/24/2022]
Abstract
Mutations in the Artemis gene are causative in a subset of human severe combined immunodeficiencies (SCIDs) and Artemis-deficient cells exhibit radiation sensitivity and defective V(D)J recombination, implicating Artemis function in non-homologous end joining (NHEJ). Here we show that Artemis-deficient cells from Athabascan-speaking Native American SCID patients (SCIDA) display significantly elevated sensitivity to ionizing radiation (IR) but only a very subtle defect in DNA double-strand (DSB) break repair in contrast to the severe DSB repair defect of NHEJ-deficient cells. Primary human SCIDA fibroblasts accumulate and exhibit persistent arrest at both the G1/S and G2/M boundaries in response to IR, consistent with the presence of persistent DNA damage. Artemis protein is phosphorylated in a PI3-like kinase-dependent manner after either IR or a number of other DNA damaging treatments including etoposide, but SCIDA cells are not hypersensitive to treatment with etoposide. Inhibitor studies with various DNA damaging agents establish multiple phosphorylation states and suggest multiple kinases function in Artemis phosphorylation. We observe that Artemis phosphorylation occurs rapidly after irradiation like that of histone H2AX. However, unlike H2AX, Artemis de-phosphorylation is uncoupled from overall DNA repair and correlates instead with cell cycle progression to or through mitosis. Our results implicate a direct and non-redundant function of Artemis in the repair of a small subset of DNA double-strand breaks, possibly those with hairpin termini, which may account for the pronounced radiation sensitivity observed in Artemis-deficient cells.
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Affiliation(s)
- Junhua Wang
- Life Sciences Division, Department of Molecular Biology, Lawrence Berkeley National Laboratory, Mail Stop 74-157, 1 Cyclotron Road, Berkeley, CA 94720, USA
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229
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Bonilla FA, Bernstein IL, Khan DA, Ballas ZK, Chinen J, Frank MM, Kobrynski LJ, Levinson AI, Mazer B, Nelson RP, Orange JS, Routes JM, Shearer WT, Sorensen RU. Practice parameter for the diagnosis and management of primary immunodeficiency. Ann Allergy Asthma Immunol 2005; 94:S1-63. [PMID: 15945566 DOI: 10.1016/s1081-1206(10)61142-8] [Citation(s) in RCA: 311] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Francisco A Bonilla
- Department of Medicine, Children's Hospital Boston, Harvard Medical School, Boston, Massachusetts, USA
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230
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Wada T, Toma T, Okamoto H, Kasahara Y, Koizumi S, Agematsu K, Kimura H, Shimada A, Hayashi Y, Kato M, Yachie A. Oligoclonal expansion of T lymphocytes with multiple second-site mutations leads to Omenn syndrome in a patient with RAG1-deficient severe combined immunodeficiency. Blood 2005; 106:2099-101. [PMID: 15845893 DOI: 10.1182/blood-2005-03-0936] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Omenn syndrome (OS) is a rare primary immunodeficiency characterized by the presence of activated/oligoclonal T cells, eosinophilia, and the absence of circulating B cells. OS patients carry leaky mutations of recombination activating genes (RAG1 or RAG2) resulting in partial V(D)J recombination activity, whereas null mutations cause severe combined immunodeficiency with absence of mature T and B cells (T-B- SCID). Here we describe somatic mosaicism due to multiple second-site mutations in a patient with RAG1 deficiency. We found that he is homozygous for a single base deletion in the RAG1 gene, which results in frameshift and likely abrogates the protein function. However, the patient showed typical OS features. Molecular analysis revealed that several second-site mutations, all of which restored the RAG1 reading frame and resulted in missense mutations, were demonstrated in his T cells. These findings suggest that his revertant T-cell mosaicism is responsible for OS phenotype switched from T-B- SCID.
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Affiliation(s)
- Taizo Wada
- Department of Pediatrics, Graduate School of Medical Science, Kanazawa University, 13-1 Takaramachi, Kanazawa 920-8641, Japan.
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231
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Musio A, Marrella V, Sobacchi C, Rucci F, Fariselli L, Giliani S, Lanzi G, Notarangelo LD, Delia D, Colombo R, Vezzoni P, Villa A. Damaging-agent sensitivity of Artemis-deficient cell lines. Eur J Immunol 2005; 35:1250-6. [PMID: 15770702 DOI: 10.1002/eji.200425555] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Defects in repairing double-strand breaks can lead to genome instability and tumorigenesis. In humans, most T(-)B(-) severe combined immunodeficiencies (SCID) have a defect in either the RAG1 or RAG2 gene, are not radiosensitive and do not show genome instability. On the contrary, a minority of T(-)B(-) SCID patients have abnormalities in the Artemis gene and are moderately radiosensitive. Artemis-deficient cells are unable to process hairpin ends after RAG cleavage, but hairpin opening activity alone does not explain the moderate X-ray sensitivity of Artemis-deficient cells. We report here that, at variance with what has been described in mice, cell lines from Artemis(-/-) patients are moderately sensitive to mitomycin C and show only a low to moderate increase in genomic instability, both spontaneously and after exposure to ionizing radiations. There is some heterogeneity in the levels of DNA damage sensitivity and genome instability, which could in part be due to different effects of the specific mutation involved or to genetic background, which may not always represent null alleles. This data supports the hypothesis that, in addition to playing a role in hairpin opening during the V(D)J recombination process, Artemis is involved in the repair of a subset of DNA damage whose exact nature is still undefined.
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Affiliation(s)
- Antonio Musio
- Istituto di Tecnologie Biomediche, CNR, Segrate, Italy
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232
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Umetsu SE, Lee WL, McIntire JJ, Downey L, Sanjanwala B, Akbari O, Berry GJ, Nagumo H, Freeman GJ, Umetsu DT, DeKruyff RH. TIM-1 induces T cell activation and inhibits the development of peripheral tolerance. Nat Immunol 2005; 6:447-54. [PMID: 15793575 DOI: 10.1038/ni1186] [Citation(s) in RCA: 248] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2004] [Accepted: 02/01/2005] [Indexed: 02/01/2023]
Abstract
We have examined the function of TIM-1, encoded by a gene identified as an 'atopy susceptibility gene' (Havcr1*), and demonstrate here that TIM-1 is a molecule that costimulates T cell activation. TIM-1 was expressed on CD4(+) T cells after activation and its expression was sustained preferentially in T helper type 2 (T(H)2) but not T(H)1 cells. In vitro stimulation of CD4(+) T cells with a TIM-1-specific monoclonal antibody and T cell receptor ligation enhanced T cell proliferation; in T(H)2 cells, such costimulation greatly enhanced synthesis of interleukin 4 but not interferon-gamma. In vivo, the use of antibody to TIM-1 plus antigen substantially increased production of both interleukin 4 and interferon-gamma in unpolarized T cells, prevented the development of respiratory tolerance, and increased pulmonary inflammation. Our studies suggest that immunotherapies that regulate TIM-1 function may downmodulate allergic inflammatory diseases.
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Affiliation(s)
- Sarah E Umetsu
- Department of Pediatrics, Stanford University, Stanford, California 94305, USA
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233
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Cavadini P, Vermi W, Facchetti F, Fontana S, Nagafuchi S, Mazzolari E, Sediva A, Marrella V, Villa A, Fischer A, Notarangelo LD, Badolato R. AIRE deficiency in thymus of 2 patients with Omenn syndrome. J Clin Invest 2005. [DOI: 10.1172/jci200523087] [Citation(s) in RCA: 129] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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234
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Cavadini P, Vermi W, Facchetti F, Fontana S, Nagafuchi S, Mazzolari E, Sediva A, Marrella V, Villa A, Fischer A, Notarangelo LD, Badolato R. AIRE deficiency in thymus of 2 patients with Omenn syndrome. J Clin Invest 2005; 115:728-32. [PMID: 15696198 PMCID: PMC546458 DOI: 10.1172/jci23087] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2004] [Accepted: 12/07/2004] [Indexed: 12/11/2022] Open
Abstract
Omenn syndrome is a severe primary immunodeficiency with putative autoimmune manifestations of the skin and gastrointestinal tract. The disease is caused by hypomorphic mutations in recombination-activating genes that impair but do not abolish the process of VDJ recombination, leading to the generation of autoreactive T cells with a highly restricted receptor repertoire. Loss of central tolerance in genetically determined autoimmune diseases, e.g., autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy, is associated with defective expression by medullary thymic epithelial cells of AIRE, the transcription activator that induces thymic expression of tissue-specific antigens. Analysis of AIRE expression in the thymi of 2 Omenn syndrome patients and 1 SCID patient, by real-time RT-PCR and immunohistochemistry, demonstrated a profound reduction in the levels of AIRE mRNA and protein in patients as compared with a normal control subject. Lack of AIRE was associated with normal or even increased levels of keratin and lymphotoxin-beta receptor mRNAs, while mRNAs of the self-antigens insulin, cytochrome P450 1a2, and fatty acid-binding protein were undetectable in thymi from immunodeficiency patients. These results demonstrate that deficiency of AIRE expression is observed in severe immunodeficiencies characterized by abnormal T cell development and suggest that in Omenn syndrome, the few residual T cell clones that develop may escape negative selection and thereafter expand in the periphery, causing massive autoimmune reactions.
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Affiliation(s)
- Patrizia Cavadini
- 1Istituto di Medicina Molecolare Angelo Nocivelli, Clinica Pediatrica, University of Brescia, Brescia, Italy
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235
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Wei XC, Dohkan JI, Kishi H, Wu CX, Kondo S, Muraguchi A. Characterization of the proximal enhancer element and transcriptional regulatory factors for murine recombination activating gene-2. Eur J Immunol 2005; 35:612-21. [PMID: 15657951 DOI: 10.1002/eji.200425185] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Recombination-activating gene (RAG)-1 and RAG-2 are essential for V(D)J recombination and are expressed specifically in lymphoid cells. We previously identified two putative enhancer elements, the proximal and distal enhancers, located at -2.6 and -8 kb, respectively, 5' upstream of mouse RAG-2, and characterized the distal enhancer element in detail. In this study, to characterize the proximal enhancer in vitro as well as in vivo, we first defined a 170-bp core enhancer element within the proximal enhancer (Ep) and determined its activity in various cells. Ep conferred enhancer activity only in B-lymphoid cell lines, but not in T- or non-lymphoid cell lines. Analysis of the transgenic mice carrying an EGFP reporter gene linked with Ep revealed that Ep activated the transcription of the reporter gene in bone marrow and spleen, but not in thymus or non-lymphoid tissues. Ep was active in both B220+IgM- and B220+IgM+ subpopulations in the bone marrow and in the B220+ subpopulation in the spleen. Using electrophoretic mobility shift assays and mutational assays, we found that Ikaros and CCAAT/enhancer binding protein cooperatively bind Ep and function as the transcription factors responsible for B cell-specific enhancer activity. These results demonstrate the role of Ep as a cis-regulatory enhancer element for RAG-2-specific expression in B-lymphoid lineages.
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Affiliation(s)
- Xing-Cheng Wei
- Department of Immunology, Faculty of Medicine, Toyama Medical and Pharmaceutical University, Sugitani, Toyama, Japan
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236
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De P, Rodgers KK. Putting the pieces together: identification and characterization of structural domains in the V(D)J recombination protein RAG1. Immunol Rev 2005; 200:70-82. [PMID: 15242397 DOI: 10.1111/j.0105-2896.2004.00154.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
V(D)J recombination generates functional immunoglobulin and T-cell receptor genes in developing lymphocytes. The recombination-activating gene 1 (RAG1) and RAG2 proteins catalyze site-specific DNA cleavage in this recombination process. Biochemical studies have identified catalytically active regions of each protein, referred to as the core regions. Here, we review our progress in the identification and characterization, in biophysical and biochemical terms, of topologically independent domains within both the non-core and core regions of RAG1. Previous characterizations of a structural domain identified in the non-core region of RAG1 from residues 265-380, referred to as the zinc-binding dimerization domain, are discussed. This domain contains two zinc-binding motifs, a RING finger and a C2H2 zinc finger. Core RAG1 also consists of multiple domains, each of which functions individually in one or more of the essential macromolecular interactions formed by the intact core protein. Two structural domains referred to as the central and the C-terminal domains that include residues 528-760 and 761-979 of RAG1, respectively, have been identified. The interactions of the central and C-terminal domains in core RAG1 with the recombination signal sequence (RSS) have contributed additional insight to a developing model for the RAG1-RSS complex.
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Affiliation(s)
- Pallabi De
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
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237
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Revy P, Buck D, le Deist F, de Villartay JP. The Repair of DNA Damages/Modifications During the Maturation of the Immune System: Lessons from Human Primary Immunodeficiency Disorders and Animal Models. Adv Immunol 2005; 87:237-95. [PMID: 16102576 DOI: 10.1016/s0065-2776(05)87007-5] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The immune system is the site of various genotoxic stresses that occur during its maturation as well as during immune responses. These DNA lesions/modifications are primarily the consequences of specific physiological processes such as the V(D)J recombination, the immunoglobulin class switch recombination (CSR), and the generation of somatic hypermutations (SHMs) within Ig variable domains. The DNA lesions can be introduced either by specific factors (RAG1 and RAG2 in the case of V(D)J recombination and AID in the case of CSR and SHM) or during the various phases of cellular proliferation and cellular activation. All these DNA lesions are taken care of by the diverse DNA repair machineries of the cell. Several animal models as well as human conditions have established the critical importance of these DNA lesions/modifications and their repair in the physiology of the immune system. Indeed their defects have consequences ranging from immune deficiency to development of immune malignancy. The survey of human pathology has been highly instrumental in the past in identifying key factors involved in the generation of DNA modifications (AID for the Ig CSR and generation of SHM) or the repair of specific DNA damages (Artemis for V(D)J recombination). Defects in factors involved in the cell cycle checkpoints following DNA damage also have deleterious consequences on the immune system. The continuous survey of human diseases characterized by primary immunodeficiency associated with increased sensitivity to ionizing radiation should help identify other important DNA repair factors essential for the development and maintenance of the immune system.
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Affiliation(s)
- Patrick Revy
- Développement Normal et Pathologique du Système Immunitaire, INSERM U429, Hôpital Necker, Paris, France
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238
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Blackburn MR, Kellems RE. Adenosine Deaminase Deficiency: Metabolic Basis of Immune Deficiency and Pulmonary Inflammation. Adv Immunol 2005; 86:1-41. [PMID: 15705418 DOI: 10.1016/s0065-2776(04)86001-2] [Citation(s) in RCA: 117] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
Abstract
Genetic deficiencies in the purine catabolic enzyme adenosine deaminase (ADA) in humans results primarily in a severe lymphopenia and immunodeficiency that can lead to the death of affected individuals early in life. The metabolic basis of the immunodeficiency is likely related to the sensitivity of lymphocytes to the accumulation of the ADA substrates adenosine and 2'-deoxyadenosine. Investigations using ADA-deficient mice have provided compelling evidence to support the hypothesis that T and B cells are sensitive to increased concentrations of 2'-deoxyadenosine that kill cells through mechanisms that involve the accumulation of dATP and the induction of apoptosis. In addition to effects on the developing immune system, ADA-deficient humans exhibit phenotypes in other physiological systems including the renal, neural, skeletal, and pulmonary systems. ADA-deficient mice develop similar abnormalities that are dependent on the accumulation of adenosine and 2'-deoxyadenosine. Detailed analysis of the pulmonary insufficiency seen in ADA-deficient mice suggests that the accumulation of adenosine in the lung can directly access cellular signaling pathways that lead to the development and exacerbation of chronic lung disease. The ability of adenosine to regulate aspects of chronic lung disease is likely mediated by specific interactions with adenosine receptor subtypes on key regulatory cells. Thus, the examination of ADA deficiency has identified the importance of purinergic signaling during lymphoid development and in the regulation of aspects of chronic lung disease.
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Affiliation(s)
- Michael R Blackburn
- Department of Biochemistry and Molecular Biology, University of Texas Health Science Center at Houston, Houston, TX 77030 USA
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239
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Abstract
SCID, a syndrome characterized by the absence of T cells and adaptive immunity, can result from mutations in multiple genes that encode components of the immune system. Three such components are cytokine receptor chains or signaling molecules, five are needed for antigen receptor development, one is adenosine deaminase--a purine salvage pathway enzyme, and the last is a phosphatase, CD45. In this issue of the JCI, a report describes how complete deficiency of the CD3epsilon chain of the T cell antigen receptor/CD3 complex causes human SCID.
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MESH Headings
- Adenosine Deaminase/deficiency
- Adenosine Deaminase/genetics
- CD3 Complex/chemistry
- CD3 Complex/genetics
- Chromosomes, Human, Pair 11
- Chromosomes, Human, X
- Genetic Linkage
- Genetic Markers
- Humans
- Leukocyte Common Antigens/genetics
- Models, Biological
- Mutation
- Pedigree
- Protein Subunits/chemistry
- Protein Subunits/genetics
- Receptor-CD3 Complex, Antigen, T-Cell/deficiency
- Receptor-CD3 Complex, Antigen, T-Cell/genetics
- Receptors, Antigen, T-Cell/deficiency
- Receptors, Antigen, T-Cell/genetics
- Receptors, Cytokine/metabolism
- Severe Combined Immunodeficiency/etiology
- Severe Combined Immunodeficiency/genetics
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Affiliation(s)
- Rebecca H Buckley
- Department of Pediatrics, Duke University Medical Center, Durham, North Carolina, USA.
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240
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de Saint Basile G, Geissmann F, Flori E, Uring-Lambert B, Soudais C, Cavazzana-Calvo M, Durandy A, Jabado N, Fischer A, Le Deist F. Severe combined immunodeficiency caused by deficiency in either the delta or the epsilon subunit of CD3. J Clin Invest 2004; 114:1512-7. [PMID: 15546002 PMCID: PMC525745 DOI: 10.1172/jci22588] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2004] [Accepted: 08/24/2004] [Indexed: 02/02/2023] Open
Abstract
We investigated the molecular mechanism underlying a severe combined immunodeficiency characterized by the selective and complete absence of T cells. The condition was found in 5 patients and 2 fetuses from 3 consanguineous families. Linkage analysis performed on the 3 families revealed that the patients were carrying homozygous haplotypes within the 11q23 region, in which the genes encoding the gamma, delta, and epsilon subunits of CD3 are located. Patients and affected fetuses from 2 families were homozygous for a mutation in the CD3D gene, and patients from the third family were homozygous for a mutation in the CD3E gene. The thymus from a CD3delta-deficient fetus was analyzed and revealed that T cell differentiation was blocked at entry into the double positive (CD4+CD8+) stage with the accumulation of intermediate CD4-single positive cells. This indicates that CD3delta plays an essential role in promoting progression of early thymocytes toward double-positive stage. Altogether, these findings extend the known molecular mechanisms underlying severe combined immunodeficiency to a new deficiency, i.e., CD3epsilon deficiency, and emphasize the essential roles played by the CD3epsilon and CD3delta subunits in human thymocyte development, since these subunits associate with both the pre-TCR and the TCR.
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241
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Notarangelo LD, Mazzolari E, Forino C, Giliani S. Mechanisms of primary immunodeficiencies: from bed-side to bench and back. ACTA ACUST UNITED AC 2004. [DOI: 10.1016/j.ddmec.2004.10.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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242
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Affiliation(s)
- Megan S Lim
- Department of Pathology, University of Utah, Salt Lake City, USA.
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243
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244
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Basile GDS, Geissmann F, Flori E, Uring-Lambert B, Soudais C, Cavazzana-Calvo M, Durandy A, Jabado N, Fischer A, Deist FL. Severe combined immunodeficiency caused by deficiency in either the δ or the ε subunit of CD3. J Clin Invest 2004. [DOI: 10.1172/jci200422588] [Citation(s) in RCA: 115] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
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245
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Friedrich W, Müller SM. Allogeneic stem cell transplantation for treatment of immunodeficiency. ACTA ACUST UNITED AC 2004; 26:109-18. [PMID: 15368077 DOI: 10.1007/s00281-004-0158-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2004] [Accepted: 04/18/2004] [Indexed: 11/28/2022]
Abstract
Primary immunodeficiencies constitute a group of highly complex congenital disorders commonly characterized by an extremely poor prognosis. Allogeneic hematopoietic stem cell transplantation has the potential to establish a permanently functioning immune system and represents a curative approach in many of these disorders. In this review several aspects of stem cell transplantation are presented, with an emphasis on the mechanism of immune reconstitution in severe combined immunodeficiency diseases. In this disorder transplant modalities vary, and also include transplantation without cytoreductive conditioning. Clinical results are summarized based on recent analysis performed in large patient cohorts, which have shown steady improvements and have led to a marked change in the prognosis of patients with primary immunodeficiencies.
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Affiliation(s)
- Wilhelm Friedrich
- Department of Pediatrics, University of Ulm, Prittwitzstrasse 43, 89075 Ulm, Germany.
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246
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Abstract
Autoreactive antibodies are etiologic agents in a number of autoimmune diseases. Like all other antibodies these antibodies are produced in developing B cells by V(D)J recombination in the bone marrow. Three mechanisms regulate autoreactive B cells: deletion, receptor editing, and anergy. Here we review the prevalence of autoantibodies in the initial antibody repertoire, their regulation by receptor editing, and the role of the recombinase proteins (RAG1 and RAG2) in this process.
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Affiliation(s)
- Mila Jankovic
- Laboratory of Molecular Immunology, The Rockefeller University, New York, New York 10021, USA.
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247
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Le Deist F, Poinsignon C, Moshous D, Fischer A, de Villartay JP. Artemis sheds new light on V(D)J recombination. Immunol Rev 2004; 200:142-55. [PMID: 15242402 DOI: 10.1111/j.0105-2896.2004.00169.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
V(D)J recombination represents one of the three mechanisms that contribute to the diversity of the immune repertoire of B lymphocytes and T lymphocytes. It also constitutes a major checkpoint during the development of the immune system. Indeed, any V(D)J recombination deficiency leads to a block of B-cell and T-cell maturation in humans and animal models, leading to severe combined immunodeficiency (T-B-SCID). Nine factors have been identified so far to participate in V(D)J recombination. The discovery of Artemis, mutated in a subset of T-B-SCID, provided some new information regarding one of the missing V(D)J recombinase activities: hairpin opening at coding ends prior to DNA repair of the recombination activating genes 1/2-generated DNA double-strand break. New conditions of immune deficiency in humans are now under investigations and should lead to the identification of additional V(D)J recombination/DNA repair factors.
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Affiliation(s)
- Françoise Le Deist
- Développement Normal et Pathologique du Système Immunitaire, INSERM U429, Paris, France
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248
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Prag S, Collett G, Adams J. Molecular analysis of muskelin identifies a conserved discoidin-like domain that contributes to protein self-association. Biochem J 2004; 381:547-59. [PMID: 15084145 PMCID: PMC1133863 DOI: 10.1042/bj20040253] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2004] [Revised: 04/08/2004] [Accepted: 04/15/2004] [Indexed: 12/28/2022]
Abstract
Muskelin is an intracellular protein with a C-terminal kelch-repeat domain that was initially characterized as having functional involvement in cell spreading on the extracellular matrix glycoprotein thrombospondin-1. As one approach to understanding the functional properties of muskelin, we have combined bioinformatic and biochemical studies. Through analysis of a new dataset of eight animal muskelins, we showed that the N-terminal region of the polypeptide corresponds to a predicted discoidin-like domain. This domain architecture is conserved in fungal muskelins and reveals a structural parallel between the muskelins and certain extracellular fungal galactose oxidases, although the phylogeny of the two groups appears distinct. In view of the fact that a number of kelch-repeat proteins have been shown to self-associate, co-immunoprecipitation, protein pull-down assays and studies of cellular localization were carried out with wild-type, deletion mutant and point mutant muskelins to investigate the roles of the discoidin-like and kelch-repeat domains. We obtained evidence for cis- and trans-interactions between the two domains. These studies provide evidence that muskelin self-associates through a head-to-tail mechanism involving the discoidin-like domain.
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Key Words
- discoidin domain
- fungi
- galactose oxidase
- kelch repeat
- muskelin
- β-propeller
- btb/poz domain, bric-a-brac, tramtrack, broad-complex/poxvirus and zinc finger domain
- cdd, conserved domain database
- ctlh motif, c-terminal to lish motif
- dtt, dithiothreitol
- ecm, extracellular matrix
- egfp, enhanced green fluorescent protein
- egfp–mk, egpf fused to muskelin
- egfp–mkkc, egpf fused to amino acids 244–735 of muskelin
- egfp–mkdd and gst-mkdd, egfp and gst respectively fused to the muskelin discoidin-like domain
- est, expressed sequence tag
- fgi, fungal genome initiative
- gst, glutathione s-transferase
- lish motif, lissencephaly-1 homology motif
- orf, open reading frame
- psi, proteasome inhibitor i [benzyloxycarbonyl-ile-glu(otbu)-ala-leu-cho]
- smart, simple modular architecture research tool
- smc, smooth muscle cell
- wicgr, whitehead institute center for genome research
- z-llf-cho, benzyloxycarbonyl-leu-leu-phenylalaninal
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Affiliation(s)
- Soren Prag
- *Department of Cell Biology, Lerner Research Institute, Cleveland Clinic Foundation, 9500 Euclid Avenue, Cleveland, OH 44195, U.S.A
- †MRC Laboratory for Molecular Cell Biology and Department of Biochemistry and Molecular Biology, University College London, Gower St., London WC1E 6BT, U.K
| | - Georgina D. M. Collett
- †MRC Laboratory for Molecular Cell Biology and Department of Biochemistry and Molecular Biology, University College London, Gower St., London WC1E 6BT, U.K
| | - Josephine C. Adams
- *Department of Cell Biology, Lerner Research Institute, Cleveland Clinic Foundation, 9500 Euclid Avenue, Cleveland, OH 44195, U.S.A
- †MRC Laboratory for Molecular Cell Biology and Department of Biochemistry and Molecular Biology, University College London, Gower St., London WC1E 6BT, U.K
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249
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Wu CX, Zhao WP, Kishi H, Dokan J, Jin ZX, Wei XC, Yokoyama KK, Muraguchi A. Activation of mouse RAG-2 promoter by Myc-associated zinc finger protein. Biochem Biophys Res Commun 2004; 317:1096-102. [PMID: 15094381 DOI: 10.1016/j.bbrc.2004.03.159] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2004] [Indexed: 11/24/2022]
Abstract
Recombination activating gene-1 (RAG-1) and RAG-2 are expressed specifically in lymphocytes undergoing the antigen receptor gene rearrangement during the lymphocyte development. Our previous study showed that the -41 to -17 nucleotides (nt) 5' -upstream region of mouse RAG-2 were pre-requisite for the core promoter activity and that Pax-5/c-Myb/LEF-1 protein-protein complex was responsible for its activity in immature B cells. In this study, we show that the -65/-42 sequence, the non-conserved sequence between human and mouse RAG-2 promoter, is necessary for the full promoter activity for mouse RAG-2. Electrophoresis mobility shift assay revealed that Myc-associated zinc finger protein (MAZ) as well as SP1/3 binds a GA box in this region. Using chromatin immunoprecipitation, we show that MAZ binds the RAG-2 promoter region in pre-B cells. Furthermore, we show that MAZ synergistically activates the murine RAG-2 promoter with Pax-5/c-Myb/LEF-1 complex. These results first demonstrate that MAZ participates in activation of mouse RAG-2 promoter.
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Affiliation(s)
- Chun-Xiao Wu
- Department of Immunology, Faculty of Medicine, Toyama Medical and Pharmaceutical University, 2630, Sugitani, Toyama 930-0194, Japan
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250
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Abstract
In the fifty years since Ogden Bruton discovered agammaglobulinemia, more than 100 additional immunodeficiency syndromes have been described. These disorders may involve one or more components of the immune system, including T, B, and NK lymphocytes; phagocytic cells; and complement proteins. Most are recessive traits, some of which are caused by mutations in genes on the X chromosome, others in genes on autosomal chromosomes. Until the past decade, there was little insight into the fundamental problems underlying a majority of these conditions. Many of the primary immunodeficiency diseases have now been mapped to specific chromosomal locations, and the fundamental biologic errors have been identified in more than 3 dozen. Within the past decade the molecular bases of 7 X-linked immunodeficiency disorders have been reported: X-linked immunodeficiency with Hyper IgM, X-linked lymphoproliferative disease, X-linked agammaglobulinemia, X-linked severe combined immunodeficiency, the Wiskott-Aldrich syndrome, nuclear factor kappaB essential modulator (NEMO or IKKg), and the immune dysregulation polyendocrinopathy (IPEX) syndrome. The abnormal genes in X-linked chronic granulomatous disease (CGD) and properdin deficiency had been identified several years earlier. In addition, there are now many autosomal recessive immunodeficiencies for which the molecular bases have been discovered. These new advances will be reviewed, with particular emphasis on the pulmonary complications of some of these diseases. In some cases there are unique features of lung abnormalities in specific defects. Infections obviously account for most of these complications, but the host reaction to infection often leads to characteristic findings that can be helpful diagnostically. Finally, advances in treatment of the underlying diseases as well as their infectious complications will be covered.
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Affiliation(s)
- Rebecca H Buckley
- Departments of Pediatrics and Immunology, Duke University Medical Center, Durham, NC 27710, USA.
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