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Fayez EA, Qazvini FF, Mahmoudi SM, Khoei S, Vesaltalab M, Teimourian S. Diagnosis of radiosensitive severe combined immunodeficiency disease (RS-SCID) by Comet Assay, management of bone marrow transplantation. Immunobiology 2020; 225:151961. [PMID: 32517885 DOI: 10.1016/j.imbio.2020.151961] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2020] [Revised: 05/07/2020] [Accepted: 05/15/2020] [Indexed: 11/16/2022]
Abstract
BACKGROUND AND OBJECTIVE Severe combined immunodeficiency disease (SCID) is a rare inherited severe immunodeficiency, in which functions of T cells and B cells are impaired. SCID is inherited either in X-linked recessive, or autosomal recessive forms, and is either radiosensitive or radioresistant. Artemis (DCLRE1C gene), DNA ligase IV, DNA-PKC, and Cernunnos/XLF proteins are regarded as NHEJ (Non-Homologous End-Joining) proteins that are involved in the repair process of double-strand DNA breaks and their mutations would lead to cellular radiosensitivity. Diagnostic radiosensitivity assays are important for the management of clinical BMT (Bone Marrow Transplantation) conditions, such as what conditioning agents and doses should be used. MATERIALS AND METHODS In this study, five SCID patients and healthy controls were examined. Skin fibroblasts were cultured. After X-irradiation, cells either underwent clonogenic assay or incubated to allow DNA repair and examined by the alkaline comet assay. Finally, DCLRE1C, RAG-1, and RAG-2 genes sequenced. RESULTS By clonogenic assay, three patients were detected as radiosensitive with possible mutations in NHEJ genes such as DCLRE1C gene. The percentage of DNA in the tail measured by comet assay, in all three patients, was significantly different from the two other patients and the control group (p-value < 0.05). By using Sanger sequencing, a mutation in DCLRE1C gene was detected in one of the radiosensitive patients and two mutations in RAG-1, and RAG-2 genes were detected in the two radioresistant patients. CONCLUSION Our findings suggest that comet assay is a fast technique for the diagnosis of the radiosensitive form of SCID and is very suitable for the timely diagnosis of RS-SCID before BMT.
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Affiliation(s)
- Elham Alipour Fayez
- Department of Immunology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Fatemeh Farajihaye Qazvini
- Department of Clinical Biochemistry and Laboratory Medicine, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Seyedeh Marzeyeh Mahmoudi
- Department of Cell and Molecular Biology, Islamic Azad University, Science and Research Branch. Tehran, Iran
| | - Samideh Khoei
- Department of Medical Physics, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Matin Vesaltalab
- School of Medicine, Bandar Abbas University of Medical Science, Bandar Abbas, Iran
| | - Shahram Teimourian
- Department of Medical Genetics, School of Medicine, Iran University of Medical Sciences, Tehran, Iran.
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Holgersson A, Erdal H, Nilsson A, Lewensohn R, Kanter L. Expression of DNA-PKcs and Ku86, but not Ku70, differs between lymphoid malignancies. Exp Mol Pathol 2004; 77:1-6. [PMID: 15215044 DOI: 10.1016/j.yexmp.2004.02.001] [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] [Received: 01/25/2004] [Indexed: 10/26/2022]
Abstract
We have investigated the role of DNA-dependent protein kinase (DNA-PK) and related it to proliferation and maturation of different lymphoid malignancies. DNA-PK and Ki-67 protein content was investigated in tumour samples of lymphoid malignancies, obtained from patients with low- and high-grade lymphomas, acute lymphoblastic leukaemia and multiple myeloma. All patients were untreated before sampling. Normal bone marrow, reactive tonsillar tissue and ordinary lymph node tissue were used as controls. We show here that lymphoid malignancies display differences in DNA-PK protein expression. Low-grade lymphoma, appearing as chronic lymphocytic leukaemia (CLL) displayed a significantly lower frequency of cells staining positive for DNA-PKcs and Ku86, but surprisingly not for Ku70, compared with acute lymphoblastic leukaemia (ALL) cells. When material from individual CLL patients was investigated, cells from lymph nodes showed a higher frequency of positive cells with respect to all DNA-PK subunits, compared with CLL cells infiltrating the bone marrow. High-grade lymphoma lymph node samples showed an increased frequency of cells staining positive for DNA-PKcs, Ku86 and Ki-67 compared with lymph node samples from low-grade lymphoma patients. Again, no difference in the Ku70 levels between the two lymphoma entities was noted. In multiple myeloma, the frequency of cells with positive staining for DNA-PKcs was similar to that detected in ALL and high-grade lymphoma. We conclude that with the exception of multiple myeloma, expression of DNA-PK coincides with the degree of maturation of lymphoid malignancies. In low- and high-grade lymphoma, DNA-PK is associated with the proliferation rate.
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Affiliation(s)
- Asa Holgersson
- Unit of Medical Radiation Biology, Karolinska Institutet, CCK, Stockholm, Sweden
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Abstract
One of the most toxic insults a cell can incur is a disruption of its linear DNA in the form of a double-strand break (DSB). Left unrepaired, or repaired improperly, these lesions can result in cell death or neoplastic transformation. Despite these dangers, lymphoid cells purposely introduce DSBs into their genome to maximize the diversity and effector functions of their antigen receptor genes. While the generation of breaks requires distinct lymphoid-specific factors, their resolution requires various ubiquitously expressed DNA-repair proteins, known collectively as the non-homologous end-joining pathway. In this review, we discuss the factors that constitute this pathway as well as the evidence of their involvement in two lymphoid-specific DNA recombination events.
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Affiliation(s)
- Sean Rooney
- Howard Hughes Medical Institute, The Children's Hospital, The Department of Genetics, Harvard Medical School and The Center for Blood Research, Boston, MA 02115, USA
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Chen L, Huang S, Lee L, Davalos A, Schiestl RH, Campisi J, Oshima J. WRN, the protein deficient in Werner syndrome, plays a critical structural role in optimizing DNA repair. Aging Cell 2003; 2:191-9. [PMID: 12934712 DOI: 10.1046/j.1474-9728.2003.00052.x] [Citation(s) in RCA: 117] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Werner syndrome (WS) predisposes patients to cancer and premature aging, owing to mutations in WRN. The WRN protein is a RECQ-like helicase and is thought to participate in DNA double-strand break (DSB) repair by non-homologous end joining (NHEJ) or homologous recombination (HR). It has been previously shown that non-homologous DNA ends develop extensive deletions during repair in WS cells, and that this WS phenotype was complemented by wild-type (wt) WRN. WRN possesses both 3' --> 5' exonuclease and 3' --> 5' helicase activities. To determine the relative contributions of each of these distinct enzymatic activities to DSB repair, we examined NHEJ and HR in WS cells (WRN-/-) complemented with either wtWRN, exonuclease-defective WRN (E-), helicase-defective WRN (H-) or exonuclease/helicase-defective WRN (E-H-). The single E-and H- mutants each partially complemented the NHEJ abnormality of WRN-/- cells. Strikingly, the E-H- double mutant complemented the WS deficiency nearly as efficiently as did wtWRN. Similarly, the double mutant complemented the moderate HR deficiency of WS cells nearly as well as did wtWRN, whereas the E- and H- single mutants increased HR to levels higher than those restored by either E-H- or wtWRN. These results suggest that balanced exonuclease and helicase activities of WRN are required for optimal HR. Moreover, WRN appears to play a structural role, independent of its enzymatic activities, in optimizing HR and efficient NHEJ repair. Another human RECQ helicase, BLM, suppressed HR but had little or no effect on NHEJ, suggesting that mammalian RECQ helicases have distinct functions that can finely regulate recombination events.
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Affiliation(s)
- Lishan Chen
- Department of Pathology, University of Washington, Seattle, WA 98195-7470, USA
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5
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Abstract
Genetic defects in T-cell function lead to susceptibility to infections or to other clinical problems that are more grave than those seen in disorders resulting in antibody deficiency alone. Those affected usually present during infancy with either common or opportunistic infections and rarely survive beyond infancy or childhood. The spectrum of T-cell defects ranges from the syndrome of severe combined immunodeficiency, in which T-cell function is absent, to combined immunodeficiency disorders in which there is some, but not adequate, T-cell function for a normal life span. Recent discoveries of the molecular causes of many of these defects have led to a new understanding of the flawed biology underlying the ever-growing number of defects. Most of these conditions could be diagnosed by means of screening for lymphopenia or for T-cell deficiency in cord blood at birth. Early recognition of those so afflicted is essential to the application of the most appropriate treatments for these conditions at a very early age. The latter treatments include both transplantation and gene therapy in addition to immunoglobulin replacement. Fully defining the molecular defects of such patients is also essential for genetic counseling of family members and prenatal diagnosis.
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Affiliation(s)
- Rebecca H Buckley
- Division of Allergy and Immunology, Department of Pediatrics, Duke University Medical Center, Durham, NC 27710, USA
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Chen ML, Kuo CL. A conserved sequence block in the murine and human T cell receptor Jα loci interacts with developmentally regulated nucleoprotein complexesin vitroand associates with GATA-3 and Octamer-binding factorsin vivo. Eur J Immunol 2001. [DOI: 10.1002/1521-4141(200106)31:6<1696::aid-immu1696>3.0.co;2-n] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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Sekiguchi JM, Gao Y, Gu Y, Frank K, Sun Y, Chaudhuri J, Zhu C, Cheng HL, Manis J, Ferguson D, Davidson L, Greenberg ME, Alt FW. Nonhomologous end-joining proteins are required for V(D)J recombination, normal growth, and neurogenesis. COLD SPRING HARBOR SYMPOSIA ON QUANTITATIVE BIOLOGY 2001; 64:169-81. [PMID: 11232282 DOI: 10.1101/sqb.1999.64.169] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Affiliation(s)
- J M Sekiguchi
- Howard Hughes Medical Institute, Children's Hospital, Center for Blood Research, and Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA
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Yeo TC, Xia D, Hassouneh S, Yang XO, Sabath DE, Sperling K, Gatti RA, Concannon P, Willerford DM. V(D)J rearrangement in Nijmegen breakage syndrome. Mol Immunol 2000; 37:1131-9. [PMID: 11451418 DOI: 10.1016/s0161-5890(01)00026-8] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Repair of DNA double-strand breaks is essential for maintenance of genomic stability, and is specifically required for rearrangement of immunoglobulin (Ig) and T cell receptor (TCR) loci during development of the immune system. Abnormalities in these repair processes also contribute to oncogenic chromosomal rearrangements that underlie many lymphoid malignancies. Nijmegen breakage syndrome (NBS) is a rare autosomal recessive condition characterized by immunodeficiency, radiation sensitivity, and increased predisposition to lymphoid cancers bearing oncogenic Ig and TCR locus translocations. NBS patients fail to produce nibrin, a protein required for the nuclear localization and function of a DNA repair complex that includes Mre11 and Rad50. Mre11 has biochemical properties that suggest a potential role in V(D)J recombination. We studied V(D)J recombination in NBS cells in vitro and in vivo, using cell lines and peripheral blood leukocyte DNA from NBS patients. We found that NBS cells were competent to rejoin signal substrates with normal efficiency and high fidelity. Coding substrates were similarly rejoined efficiently, and coding end structures appeared normal. In B cells from NBS patients, the spectrums of IgH CDR3 regions were diverse and normally distributed. Moreover, the lengths and composition of Igkappa VJ joins and IgH VDJ joins derived from NBS and normal subjects were indistinguishable. Our data indicate that nibrin plays no essential role in V(D)J recombination and is not required for the generation of an apparently diverse B cell repertoire.
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Affiliation(s)
- T C Yeo
- Molecular Genetics Program, Virginia Mason Research Center, 1201 Ninth Avenue, Seattle, WA 98101-2795, USA
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Tachibana H, Haruta H, Ueda K, Chiwata T, Yamada K. Induction of light chain replacement in human plasma cells by caffeine is independent from both the upregulation of RAG protein expression and germ line transcription. J Biol Chem 2000; 275:5927-33. [PMID: 10681585 DOI: 10.1074/jbc.275.8.5927] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
When some human plasma cell lines are cultured with concanavalin A, the original light chain is replaced with another light chain which results from secondary VJ recombination (light chain shifting). We examined various intracellular factors involved in the induction of light chain shifting. Light chain shifting can be induced upon treatment with agents with phosphatase inhibitory activity such as caffeine and okadaic acid. Although the plasma cells used express both RAG-1 and RAG-2, the expression level of these proteins was not affected by caffeine or okadaic acid. Transcription of the germ line locus, which correlates to the locus activation for rearrangement, is also not influenced by phosphatase inhibition. However, the amount of signal broken-ended DNA intermediates generated during V(D)J rearrangement was shown to increase upon caffeine or okadaic acid treatment. The inhibitory activity of caffeine on phosphatase was the same as okadaic acid. However, caffeine exhibited much higher activity for VJ coding joint formation than okadaic acid. Therefore, although phosphatase inhibition might act, in part, on a mechanism by which V(D)J recombinase activity is regulated within the human plasma cells, other factor(s) are probably also involved in the process.
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Affiliation(s)
- H Tachibana
- Division of Bioresources, Graduate School, Kyushu University, Hakozaki 6-10-1, Higashi-ku, Fukuoka, 812-8581, Japan.
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11
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12
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Vanasse GJ, Halbrook J, Thomas S, Burgess A, Hoekstra MF, Disteche CM, Willerford DM. Genetic pathway to recurrent chromosome translocations in murine lymphoma involves V(D)J recombinase. J Clin Invest 1999; 103:1669-75. [PMID: 10377173 PMCID: PMC408389 DOI: 10.1172/jci6658] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Chromosome translocations involving antigen receptor loci are a genetic hallmark of non-Hodgkin's lymphomas in humans. Most commonly, these translocations result in juxtaposition of the immunoglobulin heavy-chain (IgH) locus with one of several cellular proto-oncogenes, leading to deregulated oncogene expression. The V(D)J recombinase, which mediates physiologic rearrangements of antigen receptor genes, may play a mechanistic role in some lymphoma translocations, although evidence is indirect. A high incidence of B-lineage lymphomas has been observed in mice with severe combined immunodeficiency (SCID) and p53-null mutations. We show that these tumors are characteristic of the pro-B-cell stage of development and that they harbor recurrent translocations involving chromosomes 12 and 15. Fluorescence in situ hybridization (FISH) shows retention of IgH sequences on the derivative chromosome 12, implying that breakpoints involve the IgH locus. Pro-B-cell lymphomas were suppressed in SCID p53(-/-) mice by a Rag-2-null mutation, demonstrating that DNA breaks generated during V(D)J recombination are required for oncogenic transformation, and suggesting that t(12;15) arise during attempted IgH rearrangement in pro-B cells. These studies indicate that the oncogenic potential inherent in antigen receptor diversification is controlled in vivo by efficient rejoining of DNA ends generated during V(D)J recombination and an intact cellular response to DNA damage.
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MESH Headings
- Animals
- B-Lymphocytes/immunology
- DNA Nucleotidyltransferases/genetics
- Gene Rearrangement, B-Lymphocyte, Heavy Chain
- Immunoglobulin Heavy Chains/genetics
- Immunophenotyping
- Lymphoma, B-Cell/enzymology
- Lymphoma, B-Cell/genetics
- Lymphoma, B-Cell/immunology
- Mice
- Mice, Inbred C57BL
- Mice, Inbred ICR
- Mice, Knockout
- Mice, SCID
- Receptors, Antigen, B-Cell/genetics
- Stem Cells/immunology
- Translocation, Genetic/immunology
- Tumor Suppressor Protein p53/deficiency
- Tumor Suppressor Protein p53/genetics
- VDJ Recombinases
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Affiliation(s)
- G J Vanasse
- Department of Medicine, University of Washington, Seattle 98195, USA
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13
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Kong FK, Chen CL, Six A, Hockett RD, Cooper MD. T cell receptor gene deletion circles identify recent thymic emigrants in the peripheral T cell pool. Proc Natl Acad Sci U S A 1999; 96:1536-40. [PMID: 9990059 PMCID: PMC15507 DOI: 10.1073/pnas.96.4.1536] [Citation(s) in RCA: 124] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Progenitor cells undergo T cell receptor (TCR) gene rearrangements during their intrathymic differentiation to become T cells. Rearrangements of the variable (V), diversity (D), and joining (J) segments of the TCR genes result in deletion of the intervening chromosomal DNA and the formation of circular episomes as a byproduct. Detection of these extrachromosomal excision circles in T cells located in the peripheral lymphoid tissues has been viewed as evidence for the existence of extrathymic T cell generation. Because all of the T cells in chickens apparently are generated in the thymus, we have employed this avian model to determine the fate of the V(D)J deletion circles. In normal animals we identified TCR Vgamma-Jgamma and Vbeta-Dbeta deletion circles in the blood, spleen, and intestines, as well as in the thymus. Thymectomy resulted in the gradual loss of these DNA deletion circles in all of the peripheral lymphoid tissues. A quantitative PCR analysis of Vgamma1-Jgamma1 and Vbeta1-Dbeta deletion circles in splenic gamma delta and Vbeta1(+) alphabeta T cells indicated that their numbers progressively decline after thymectomy with a half-life of approximately 2 weeks. Although TCR deletion circles therefore cannot be regarded as reliable indicators of in situ V(D)J rearrangement, measuring their levels in peripheral T cell samples can provide a valuable index of newly generated T cells entering the T cell pool.
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Affiliation(s)
- F K Kong
- Division of Developmental and Clinical Immunology, University of Alabama at Birmingham, Birmingham, AL 35294-3300, USA
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14
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Sterzl J. Cellular and molecular basis of immunodeficiencies: their consequences for the development and induction of the immune response. Folia Microbiol (Praha) 1998; 43:535-42. [PMID: 9821321 DOI: 10.1007/bf02820815] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
This review lists primary immunodeficiencies which essentially involve mutations in genes coding for functionally important molecules, membrane antigens (e.g., MHC), chains of lymphokine receptors, protein kinases of the signal cascade, transcription factors, and important regulators of cellular metabolism. Mutations and subsequent immunodeficiencies occur as early as during embryogenesis (lymphopoiesis-I) as well as during induction of the immune response by antigen (ligand) binding to cell receptors, TCR and BCR (immunopoiesis-II). Immunodeficiencies are classified according the developmental stages in which they occur most markedly, even in clinical terms. Some early mutations are immediately lethal, some express themselves by blocking embryonic lymphopoiesis, while other mutations do not become demonstrable until after cell stimulation by antigens (see the Tables).
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Affiliation(s)
- J Sterzl
- Division of Immunology and Gnotobiology, Academy of Sciences of Czech Republic, Prague
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15
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Sleckman BP, Bassing CH, Bardon CG, Okada A, Khor B, Bories JC, Monroe R, Alt FW. Accessibility control of variable region gene assembly during T-cell development. Immunol Rev 1998; 165:121-30. [PMID: 9850857 DOI: 10.1111/j.1600-065x.1998.tb01235.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
T-cell development is a complex and ordered process that is regulated in part by the progressive assembly and expression of antigen receptor genes. T cells can be divided into two lineages based on expression of either an alpha beta or gamma delta T-cell antigen receptor (TCR). The genes that encode the TCR beta and gamma chains lie in distinct loci, whereas the genes that encode the TCR alpha and delta chains lie in a single locus (TCR alpha/delta locus). Assembly of TCR variable region genes is mediated by a site-specific recombination process that is common among all lymphocytes. Despite the common nature of this process, recombination of TCR genes is tightly regulated within the context of the developing T cell. TCR beta, gamma and delta variable region genes are assembled prior to TCR alpha variable region genes. Furthermore, assembly of TCR beta variable region genes is regulated within the context of allelic exclusion. The regulation of rearrangement and expression of genes within the TCR alpha/delta locus presents a complicated problem. TCR alpha and delta variable region genes are assembled at different stages of T-cell development, and fully assembled TCR alpha and delta variable region genes must be expressed in distinct lineages of T cells, alpha beta and gamma delta, respectively. We have developed several experimental approaches to assess the role of cis-acting elements in regulating recombination and expression of TCR genes. Here we describe these approaches and discuss our analyses of the regulation of accessibility of the TCR beta and TCR alpha/delta loci during T-cell development.
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Affiliation(s)
- B P Sleckman
- Howard Hughes Medical Institute, Children's Hospital, Boston, MA 02115, USA
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Taccioli GE, Amatucci AG, Beamish HJ, Gell D, Xiang XH, Torres Arzayus MI, Priestley A, Jackson SP, Marshak Rothstein A, Jeggo PA, Herrera VL. Targeted disruption of the catalytic subunit of the DNA-PK gene in mice confers severe combined immunodeficiency and radiosensitivity. Immunity 1998; 9:355-66. [PMID: 9768755 DOI: 10.1016/s1074-7613(00)80618-4] [Citation(s) in RCA: 251] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The DNA-dependent protein kinase is a mammalian protein complex composed of Ku70, Ku80, and DNA-PKcs subunits that has been implicated in DNA double-strand break repair and V(D)J recombination. Here, by gene targeting, we have constructed a mouse with a disruption in the kinase domain of DNA-PKcs, generating an animal model completely devoid of DNA-PK activity. Our results demonstrate that DNA-PK activity is required for coding but not for signal join formation in mice. Although our DNA-PKcs defective mice closely resemble Scid mice, they differ by having elevated numbers of CD4+CD8+ thymocytes. This suggests that the Scid mice may not represent a null phenotype and may retain some residual DNA-PKcs function.
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Affiliation(s)
- G E Taccioli
- Department of Microbiology, Boston University School of Medicine, Massachusetts 02118, USA.
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17
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Nicolas N, Moshous D, Cavazzana-Calvo M, Papadopoulo D, de Chasseval R, Le Deist F, Fischer A, de Villartay JP. A human severe combined immunodeficiency (SCID) condition with increased sensitivity to ionizing radiations and impaired V(D)J rearrangements defines a new DNA recombination/repair deficiency. J Exp Med 1998; 188:627-34. [PMID: 9705945 PMCID: PMC2213354 DOI: 10.1084/jem.188.4.627] [Citation(s) in RCA: 128] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
The products of recombination activating gene (RAG)1 and RAG2 initiate the lymphoid-specific phase of the V(D)J recombination by creating a DNA double-strand break (dsb), leaving hairpin-sealed coding ends. The next step uses the general DNA repair machinery of the cells to resolve this dsb. Several genes involved in both V(D)J recombination and DNA repair have been identified through the analysis of in vitro mutants (Chinese hamster ovary cells) and in vivo situations of murine and equine severe combined immunodeficiency (scid). These studies lead to the description of the Ku-DNA-dependent protein kinase complex and the XRCC4 factor. A human SCID condition is characterized by an absence of B and T lymphocytes. One subset of these patients also demonstrates an increased sensitivity to the ionizing radiation of their fibroblasts and bone marrow precursor cells. This phenotype is accompanied by a profound defect in V(D)J recombination with a lack of coding joint formation, whereas signal joints are normal. Functional and genetic analyses distinguish these patients from the other recombination/repair mutants, and thus define a new group of mutants whose affected gene(s) is involved in sensitivity to ionizing radiation and V(D)J recombination.
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Affiliation(s)
- N Nicolas
- Institut National de la Santé et de la Recherche Médicale U429, Développement Normal et Pathologique du Système Immunitaire, Hôpital Necker-Enfants Malades, 75015 Paris, France
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18
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Li L, Drayna D, Hu D, Hayward A, Gahagan S, Pabst H, Cowan MJ. The gene for severe combined immunodeficiency disease in Athabascan-speaking Native Americans is located on chromosome 10p. Am J Hum Genet 1998; 62:136-44. [PMID: 9443881 PMCID: PMC1376812 DOI: 10.1086/301688] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Severe combined immunodeficiency disease (SCID) consists of a group of heterogeneous genetic disorders. The most severe phenotype, T-B- SCID, is inherited as an autosomal recessive trait and is characterized by a profound deficiency of both T cell and B cell immunity. There is a uniquely high frequency of T-B- SCID among Athabascan-speaking Native Americans (A-SCID). To localize the A-SCID gene, we conducted a genomewide search, using linkage analysis of approximately 300 microsatellite markers in 14 affected Athabascan-speaking Native American families. We obtained conclusive evidence for linkage of the A-SCID locus to markers on chromosome 10p. The maximum pairwise LOD scores 4.53 and 4.60 were obtained from two adjacent markers, D10S191 and D10S1653, respectively, at a recombination fraction of straight theta=.00. Recombination events placed the gene in an interval of approximately 6.5 cM flanked by D10S1664 and D10S674. Multipoint analysis positioned the gene for the A-SCID phenotype between D10S191 and D10S1653, with a peak LOD score of 5.10 at D10S191. Strong linkage disequilibrium was found in five linked markers spanning approximately 6.5 cM in the candidate region, suggesting a founder effect with an ancestral mutation that occurred sometime before 1300 A.D.
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Affiliation(s)
- L Li
- Department of Pediatrics, Bone Marrow Transplant Division, University of California, San Francisco, CA 94143-1278, USA
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19
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Nussenzweig A, Sokol K, Burgman P, Li L, Li GC. Hypersensitivity of Ku80-deficient cell lines and mice to DNA damage: the effects of ionizing radiation on growth, survival, and development. Proc Natl Acad Sci U S A 1997; 94:13588-93. [PMID: 9391070 PMCID: PMC28350 DOI: 10.1073/pnas.94.25.13588] [Citation(s) in RCA: 143] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
We recently have shown that mice deficient for the 86-kDa component (Ku80) of the DNA-dependent protein kinase exhibit growth retardation and a profound deficiency in V(D)J (variable, diversity, and joining) recombination. These defects may be related to abnormalities in DNA metabolism that arise from the inability of Ku80 mutant cells to process DNA double-strand breaks. To further characterize the role of Ku80 in DNA double-strand break repair, we have generated embryonic stem cells and pre-B cells and examined their response to ionizing radiation. Ku80(-/-) embryonic stem cells are more sensitive than controls to gamma-irradiation, and pre-B cells derived from Ku80 mutant mice display enhanced spontaneous and gamma-ray-induced apoptosis. We then determined the effects of ionizing radiation on the survival, growth, and lymphocyte development in Ku80-deficient mice. Ku80(-/-) mice display a hypersensitivity to gamma-irradiation, characterized by loss of hair pigmentation, severe injury to the gastrointestinal tract, and enhanced mortality. Exposure of newborn Ku80(-/-) mice to sublethal doses of ionizing radiation enhances their growth retardation and results in the induction of T cell-specific differentiation. However, unlike severe combined immunodeficient mice, radiation-induced T cell development in Ku80(-/-) mice is not accompanied by extensive thymocyte proliferation. The response of Ku80-deficient cell lines and mice to DNA-damaging agents provides important insights into the role of Ku80 in growth regulation, lymphocyte development, and DNA repair.
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Affiliation(s)
- A Nussenzweig
- Departments of Medical Physics and Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, NY 10021, USA
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Gu Y, Jin S, Gao Y, Weaver DT, Alt FW. Ku70-deficient embryonic stem cells have increased ionizing radiosensitivity, defective DNA end-binding activity, and inability to support V(D)J recombination. Proc Natl Acad Sci U S A 1997; 94:8076-81. [PMID: 9223317 PMCID: PMC21559 DOI: 10.1073/pnas.94.15.8076] [Citation(s) in RCA: 322] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/16/1997] [Indexed: 02/04/2023] Open
Abstract
V(D)J recombination requires both lymphoid-specific and generally expressed enzymatic activities. All three known generally expressed activities involved in V(D)J recombination are also involved in DNA double-strand break repair (DSBR). Two of these are components of the DNA-dependent protein kinase (DNA-PK) and include Ku80 and DNA-PK catalytic subunit (DNA-PKcs); the third, XRCC4, is a protein of unknown function. The Ku70 protein is an additional component of DNA-PK; Ku70 forms a heterodimer with Ku80 to generate the DNA end-binding component of the enzyme. To test putative functions for Ku70, we have used gene-targeted mutation to generate a murine embryonic stem cell line which lacks Ku70 expression. We find that the Ku70(-/-) cells produce no detectable Ku70 and very little Ku80, suggesting a direct interrelationship between their levels. Correspondingly, these cells lack the nonspecific DNA end-binding activity associated with Ku. Significantly, the Ku70(-/-) embryonic stem cells have markedly increased sensitivity to gamma-irradiation relative to Ku70(+/-) or wild-type embryonic stem cells. Furthermore, the Ku70(-/-) cells lack the ability to effectively rejoin signal and coding ends liberated in transiently introduced V(D)J recombination substrates by enforced RAG-1 and RAG-2 expression. We conclude that the Ku70 gene product is involved in DSBR and V(D)J recombination and confirm that the Ku70 gene can be classified as a member of the x-ray cross-complementation group 6 (XRCC6). Potential differences between the Ku70(-/-) and Ku80(-/-) V(D)J recombination defects are discussed.
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Affiliation(s)
- Y Gu
- Children's Hospital, Boston, MA 02115, USA
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21
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Willerford DM, Swat W, Alt FW. Developmental regulation of V(D)J recombination and lymphocyte differentiation. Curr Opin Genet Dev 1996; 6:603-9. [PMID: 8939716 DOI: 10.1016/s0959-437x(96)80090-6] [Citation(s) in RCA: 82] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Recent insights into the mechanism of V(D)J recombination have clarified the direct role of the products of the recombination-activating genes Rag-1 and Rag-2 in site-specific DNA cleavage at recombination signal sequences and have identified components of the general DNA double-strand break repair pathway that participate in the rejoining of the Rag-1 and Rag-2-cut receptor gene segments. The V(D)J reaction is restricted to particular antigen receptor loci in a lineage-specific and stage-specific manner. This specificity appears to involve cis-regulatory elements, some of which also regulate transcription of the germline antigen receptor loci. Early developmental steps in the T and B lineages - including phenotypic differentiation, expansion of precursors, and selection processes - are effected in a stepwise fashion by signals generated, at least in part, by the products of the functionally rearranged antigen receptor genes themselves.
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Affiliation(s)
- D M Willerford
- Howard Hughes Medical Institute, The Children's Hospital, Boston, Massachusetts 02115, USA.
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22
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Sleckman BP, Gorman JR, Alt FW. Accessibility control of antigen-receptor variable-region gene assembly: role of cis-acting elements. Annu Rev Immunol 1996; 14:459-81. [PMID: 8717521 DOI: 10.1146/annurev.immunol.14.1.459] [Citation(s) in RCA: 238] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Antigen receptor variable region genes are assembled from germline variable (V), diversity (D), and joining (J) gene segments. This process requires expression of V(D)J recombinase activity, and "accessibility" of variable gene segments to this recombinase. The exact mechanism by which variable gene segments become accessible during development is not known. However, several studies have shown that cis-acting elements that regulate transcription may also function to regulate accessibility. Here we review the evidence that transcriptional promoters, enhancers, and silencers are involved in regulation of accessibility. The manner in which these elements may combine to regulate accessibility is addressed. In addition, current and potential strategies for identifying and analyzing cis-acting elements that mediate locus accessibility are discussed.
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Affiliation(s)
- B P Sleckman
- Howard Hughes Medical Institute, Children's Hospital, Boston, Massachusetts 02115, USA
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Li Z, Alt FW. Identification of the XRCC4 gene: complementation of the DSBR and V(D)J recombination defects of XR-1 cells. Curr Top Microbiol Immunol 1996; 217:143-50. [PMID: 8787623 DOI: 10.1007/978-3-642-50140-1_10] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- Z Li
- Center for Blood Research and Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
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Li Z, Otevrel T, Gao Y, Cheng HL, Seed B, Stamato TD, Taccioli GE, Alt FW. The XRCC4 gene encodes a novel protein involved in DNA double-strand break repair and V(D)J recombination. Cell 1995; 83:1079-89. [PMID: 8548796 DOI: 10.1016/0092-8674(95)90135-3] [Citation(s) in RCA: 361] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The XR-1 Chinese hamster ovary cell line is impaired in DNA double-strand break repair (DSBR) and in ability to support V(D)J recombination of transiently introduced substrates. We now show that XR-1 cells support recombination-activating gene 1- and 2-mediated initiation of V(D)J recombination within a chromosomally integrated substrate, but are highly impaired in ability to complete the process by forming coding and recognition sequence joins. On this basis, we isolated a human cDNA sequence, termed XRCC4, whose expression confers normal V(D)J recombination ability and significant restoration of DSBR activity to XR-1, clearly demonstrating that this gene product is involved in both processes. The XRCC4 gene maps to the previously identified locus on human chromosome 5, is deleted in XR-1 cells, and encodes a ubiquitously expressed product unrelated to any described protein.
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Affiliation(s)
- Z Li
- Center for Blood Research, Harvard University Medical School, Boston, Massachusetts 02115, USA
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