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Dunn SE, Perry WA, Klein SL. Mechanisms and consequences of sex differences in immune responses. Nat Rev Nephrol 2024; 20:37-55. [PMID: 37993681 DOI: 10.1038/s41581-023-00787-w] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/26/2023] [Indexed: 11/24/2023]
Abstract
Biological sex differences refer to differences between males and females caused by the sex chromosome complement (that is, XY or XX), reproductive tissues (that is, the presence of testes or ovaries), and concentrations of sex steroids (that is, testosterone or oestrogens and progesterone). Although these sex differences are binary for most human individuals and mice, transgender individuals receiving hormone therapy, individuals with genetic syndromes (for example, Klinefelter and Turner syndromes) and people with disorders of sexual development reflect the diversity in sex-based biology. The broad distribution of sex steroid hormone receptors across diverse cell types and the differential expression of X-linked and autosomal genes means that sex is a biological variable that can affect the function of all physiological systems, including the immune system. Sex differences in immune cell function and immune responses to foreign and self antigens affect the development and outcome of diverse diseases and immune responses.
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Affiliation(s)
- Shannon E Dunn
- Department of Immunology, University of Toronto, Toronto, Ontario, Canada
- Women's College Research Institute, Women's College Hospital, Toronto, Ontario, Canada
| | - Whitney A Perry
- Division of Geographic Medicine and Infectious Diseases, Tufts Medical Center, Boston, MA, USA
| | - Sabra L Klein
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA.
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2
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Li X, Zhang W, Huang M, Ren Z, Nie C, Liu X, Yang S, Zhang X, Yang N. Selection of potential cytokeratin-18 monoclonal antibodies following IGH repertoire evaluation in mice. J Immunol Methods 2019; 474:112647. [PMID: 31421082 DOI: 10.1016/j.jim.2019.112647] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Revised: 07/12/2019] [Accepted: 08/13/2019] [Indexed: 12/12/2022]
Abstract
Cytokeratin 18 (CK18), the main scaffold protein of keratinocyte, is distributed in epithelial cells. This structural protein maintains the integrity and continuity of epithelial tissue. Cytokeratin is also frequently used as an immunohistochemical marker of tumor growth. In recent years, immune repertoire (IR) evaluation using next-generation sequencing (NGS) have become increasingly efficient. Here we deep sequenced the mouse IR of the immunoglobulin heavy chain (IGH) after CK18 immunization. We comprehensively analyzed the IR based on complementarity determining region 3 (CDR3) abundance, germline gene usage polarization, clone diversity, and lineage. We found many convergence characteristics after CK18 immunization. Convergence represents a phenomenon that antigen stimulation or pathogen exposure induces the antigen specific clone expansion and enrichment. The convergence could be used for the immune evaluation and antibody screen. After immunization, the IGHV5 gene clusters became preponderant. The abundance and length of the most frequent CDR3 both increased, nevertheless the IR diversity level decreased. From the convergent IGH repertoires, we selected and expressed six antibodies with the most frequent CDR3s and IGH V-J combinations. The ELISA results suggested all screened six antibodies bound CK18 specifically. The most potential antibody had 9.424E-10M M affinity for the interaction with the CK18. Therefore, this is the NGS platform has been first used for anti-CK18 monoclonal antibodies (MAbs) discovery. These analyses methods could also be used for vaccine evaluation.
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Affiliation(s)
- Xinyang Li
- BGI Education Center, University of Chinese Academy of Sciences, Shenzhen 518083, China; BGI-Shenzhen, Shenzhen 518083, China; China National GeneBank, BGI-Shenzhen, Shenzhen 518120, China
| | - Wei Zhang
- BGI-Shenzhen, Shenzhen 518083, China; China National GeneBank, BGI-Shenzhen, Shenzhen 518120, China
| | - Mi Huang
- BGI-Shenzhen, Shenzhen 518083, China; China National GeneBank, BGI-Shenzhen, Shenzhen 518120, China
| | - Zhe Ren
- BGI-Shenzhen, Shenzhen 518083, China; China National GeneBank, BGI-Shenzhen, Shenzhen 518120, China
| | - Chao Nie
- BGI Education Center, University of Chinese Academy of Sciences, Shenzhen 518083, China; BGI-Shenzhen, Shenzhen 518083, China; China National GeneBank, BGI-Shenzhen, Shenzhen 518120, China
| | - Xiao Liu
- BGI-Shenzhen, Shenzhen 518083, China; China National GeneBank, BGI-Shenzhen, Shenzhen 518120, China
| | - Shuang Yang
- BGI-Shenzhen, Shenzhen 518083, China; China National GeneBank, BGI-Shenzhen, Shenzhen 518120, China
| | - Xiuqing Zhang
- BGI Education Center, University of Chinese Academy of Sciences, Shenzhen 518083, China; BGI-Shenzhen, Shenzhen 518083, China; China National GeneBank, BGI-Shenzhen, Shenzhen 518120, China
| | - Naibo Yang
- BGI-Shenzhen, Shenzhen 518083, China; China National GeneBank, BGI-Shenzhen, Shenzhen 518120, China; Complete Genomics, Inc., 2904 Orchard Parkway, San Jose, CA 95134, USA.
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3
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Hou D, Ying T, Wang L, Chen C, Lu S, Wang Q, Seeley E, Xu J, Xi X, Li T, Liu J, Tang X, Zhang Z, Zhou J, Bai C, Wang C, Byrne-Steele M, Qu J, Han J, Song Y. Immune Repertoire Diversity Correlated with Mortality in Avian Influenza A (H7N9) Virus Infected Patients. Sci Rep 2016; 6:33843. [PMID: 27669665 PMCID: PMC5037391 DOI: 10.1038/srep33843] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Accepted: 09/02/2016] [Indexed: 01/09/2023] Open
Abstract
Specific changes in immune repertoires at genetic level responding to the lethal H7N9 virus are still poorly understood. We performed deep sequencing on the T and B cells from patients recently infected with H7N9 to explore the correlation between clinical outcomes and immune repertoire alterations. T and B cell repertoires display highly dynamic yet distinct clonotype alterations. During infection, T cell beta chain repertoire continues to contract while the diversity of immunoglobulin heavy chain repertoire recovers. Patient recovery is correlated to the diversity of T cell and B cell repertoires in different ways – higher B cell diversity and lower T cell diversity are found in survivors. The sequences clonally related to known antibodies with binding affinity to H7 hemagglutinin could be identified from survivors. These findings suggest that utilizing deep sequencing may improve prognostication during influenza infection and could help in development of antibody discovery methodologies for the treatment of virus infection.
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Affiliation(s)
- Dongni Hou
- Department of Pulmonary Medicine, Zhongshan Hospital, Fudan University, Shanghai, 200032, China
| | - Tianlei Ying
- Key Laboratory of Medical Molecular Virology of Ministries of Education and Health, School of Basic Medical Sciences, Fudan University, Shanghai, 200032, China
| | - Lili Wang
- Key Laboratory of Medical Molecular Virology of Ministries of Education and Health, School of Basic Medical Sciences, Fudan University, Shanghai, 200032, China
| | - Cuicui Chen
- Department of Pulmonary Medicine, Zhongshan Hospital, Fudan University, Shanghai, 200032, China
| | - Shuihua Lu
- Department of Respiratory Medicine, Shanghai Public Health Clinical Center, Fudan University, Shanghai, 201508, China
| | - Qin Wang
- Department of Pulmonary Medicine, Zhongshan Hospital, Fudan University, Shanghai, 200032, China
| | - Eric Seeley
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, University of California, San Francisco, CA 94143, USA
| | - Jianqing Xu
- Department of Respiratory Medicine, Shanghai Public Health Clinical Center, Fudan University, Shanghai, 201508, China
| | - Xiuhong Xi
- Department of Respiratory Medicine, Shanghai Public Health Clinical Center, Fudan University, Shanghai, 201508, China
| | - Tao Li
- Department of Respiratory Medicine, Shanghai Public Health Clinical Center, Fudan University, Shanghai, 201508, China
| | - Jie Liu
- Department of Pulmonary Medicine, Zhongshan Hospital, Fudan University, Shanghai, 200032, China
| | - Xinjun Tang
- Department of Pulmonary Medicine, Zhongshan Hospital, Fudan University, Shanghai, 200032, China
| | - Zhiyong Zhang
- Department of Respiratory Medicine, Shanghai Public Health Clinical Center, Fudan University, Shanghai, 201508, China
| | - Jian Zhou
- Department of Pulmonary Medicine, Zhongshan Hospital, Fudan University, Shanghai, 200032, China
| | - Chunxue Bai
- Department of Pulmonary Medicine, Zhongshan Hospital, Fudan University, Shanghai, 200032, China
| | - Chunlin Wang
- HudsonAlpha Institute for Biotechnology, Alabama, AL35806, USA
| | | | - Jieming Qu
- Department of Pulmonary Medicine, Ruijin Hospital, Shanghai Jiaotong University, Shanghai, 200025, China
| | - Jian Han
- HudsonAlpha Institute for Biotechnology, Alabama, AL35806, USA
| | - Yuanlin Song
- Department of Pulmonary Medicine, Zhongshan Hospital, Fudan University, Shanghai, 200032, China.,Department of Respiratory Medicine, Shanghai Public Health Clinical Center, Fudan University, Shanghai, 201508, China.,Department of Pulmonary Medicine, Zhongshan Hospital, Qingpu Branch, Shanghai, 200032, China
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4
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Hou D, Chen C, Seely EJ, Chen S, Song Y. High-Throughput Sequencing-Based Immune Repertoire Study during Infectious Disease. Front Immunol 2016; 7:336. [PMID: 27630639 PMCID: PMC5005336 DOI: 10.3389/fimmu.2016.00336] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Accepted: 08/19/2016] [Indexed: 11/13/2022] Open
Abstract
The selectivity of the adaptive immune response is based on the enormous diversity of T and B cell antigen-specific receptors. The immune repertoire, the collection of T and B cells with functional diversity in the circulatory system at any given time, is dynamic and reflects the essence of immune selectivity. In this article, we review the recent advances in immune repertoire study of infectious diseases, which were achieved by traditional techniques and high-throughput sequencing (HTS) techniques. HTS techniques enable the determination of complementary regions of lymphocyte receptors with unprecedented efficiency and scale. This progress in methodology enhances the understanding of immunologic changes during pathogen challenge and also provides a basis for further development of novel diagnostic markers, immunotherapies, and vaccines.
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Affiliation(s)
- Dongni Hou
- Department of Pulmonary Medicine, Zhongshan Hospital, Fudan University , Shanghai , China
| | - Cuicui Chen
- Department of Pulmonary Medicine, Zhongshan Hospital, Fudan University , Shanghai , China
| | - Eric John Seely
- Department of Medicine, Division of Pulmonary and Critical Care Medicine, University of California San Francisco , San Francisco, CA , USA
| | - Shujing Chen
- Department of Pulmonary Medicine, Zhongshan Hospital, Fudan University , Shanghai , China
| | - Yuanlin Song
- Department of Pulmonary Medicine, Zhongshan Hospital, Fudan University , Shanghai , China
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5
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Guthals A, Watrous JD, Dorrestein PC, Bandeira N. The spectral networks paradigm in high throughput mass spectrometry. MOLECULAR BIOSYSTEMS 2013; 8:2535-44. [PMID: 22610447 DOI: 10.1039/c2mb25085c] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
High-throughput proteomics is made possible by a combination of modern mass spectrometry instruments capable of generating many millions of tandem mass (MS(2)) spectra on a daily basis and the increasingly sophisticated associated software for their automated identification. Despite the growing accumulation of collections of identified spectra and the regular generation of MS(2) data from related peptides, the mainstream approach for peptide identification is still the nearly two decades old approach of matching one MS(2) spectrum at a time against a database of protein sequences. Moreover, database search tools overwhelmingly continue to require that users guess in advance a small set of 4-6 post-translational modifications that may be present in their data in order to avoid incurring substantial false positive and negative rates. The spectral networks paradigm for analysis of MS(2) spectra differs from the mainstream database search paradigm in three fundamental ways. First, spectral networks are based on matching spectra against other spectra instead of against protein sequences. Second, spectral networks find spectra from related peptides even before considering their possible identifications. Third, spectral networks determine consensus identifications from sets of spectra from related peptides instead of separately attempting to identify one spectrum at a time. Even though spectral networks algorithms are still in their infancy, they have already delivered the longest and most accurate de novo sequences to date, revealed a new route for the discovery of unexpected post-translational modifications and highly-modified peptides, enabled automated sequencing of cyclic non-ribosomal peptides with unknown amino acids and are now defining a novel approach for mapping the entire molecular output of biological systems that is suitable for analysis with tandem mass spectrometry. Here we review the current state of spectral networks algorithms and discuss possible future directions for automated interpretation of spectra from any class of molecules.
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Affiliation(s)
- Adrian Guthals
- Dept. Computer Science and Engineering, University of California, San Diego, USA
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6
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Abstract
While advances in tandem mass spectrometry (MS/MS) steadily increase the rate of generation of MS/MS spectra, standard algorithmic approaches for peptide identification recently seemed to be reaching the limit on the amount of information that could be extracted from MS/MS spectra. However, a closer look reveals that a common limiting procedure is to analyze each spectrum in isolation, even though high throughput mass spectrometry regularly generates many spectra from related peptides. By capitalizing on this redundancy we show that, similarly to the alignment of protein sequences, unidentified MS/MS spectra can also be aligned for the identification of modified and unmodified variants of the same peptide. Moreover, this alignment procedure can be iterated for the accurate grouping of multiple modification variants of the same peptides. Furthermore, the combination of shotgun proteomics with the alignment of spectra from overlapping peptides led to the development of Shotgun Protein Sequencing - similarly to the assembly of DNA reads into whole genomic sequences, we show that assembly of MS/MS spectra enables the highest ever de novo sequencing accuracy, while recovering nearly complete protein sequences. We further show that shotgun protein sequencing has the potential to overcome the limitations of -current protein sequencing approaches and thus catalyze the otherwise impractical applications of proteomics methodologies in studies of unknown proteins.
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Affiliation(s)
- Nuno Bandeira
- Center for Computational Mass Spectrometry, University of California, San Diego, La Jolla, CA, USA.
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7
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Bandeira N, Clauser KR, Pevzner PA. Shotgun protein sequencing: assembly of peptide tandem mass spectra from mixtures of modified proteins. Mol Cell Proteomics 2007; 6:1123-34. [PMID: 17446555 DOI: 10.1074/mcp.m700001-mcp200] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Despite significant advances in the identification of known proteins, the analysis of unknown proteins by MS/MS still remains a challenging open problem. Although Klaus Biemann recognized the potential of MS/MS for sequencing of unknown proteins in the 1980s, low throughput Edman degradation followed by cloning still remains the main method to sequence unknown proteins. The automated interpretation of MS/MS spectra has been limited by a focus on individual spectra and has not capitalized on the information contained in spectra of overlapping peptides. Indeed the powerful shotgun DNA sequencing strategies have not been extended to automated protein sequencing. We demonstrate, for the first time, the feasibility of automated shotgun protein sequencing of protein mixtures by utilizing MS/MS spectra of overlapping and possibly modified peptides generated via multiple proteases of different specificities. We validate this approach by generating highly accurate de novo reconstructions of multiple regions of various proteins in western diamondback rattlesnake venom. We further argue that shotgun protein sequencing has the potential to overcome the limitations of current protein sequencing approaches and thus catalyze the otherwise impractical applications of proteomics methodologies in studies of unknown proteins.
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Affiliation(s)
- Nuno Bandeira
- Department of Computer Science and Engineering, University of California San Diego, La Jolla, California 92093, USA.
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8
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van den Broek D, Bloemberg GV, Lugtenberg B. The role of phenotypic variation in rhizosphere Pseudomonas bacteria. Environ Microbiol 2006; 7:1686-97. [PMID: 16232284 DOI: 10.1111/j.1462-2920.2005.00912.x] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Colony phase variation is a regulatory mechanism at the DNA level which usually results in high frequency, reversible switches between colonies with a different phenotype. A number of molecular mechanisms underlying phase variation are known: slipped-strand mispairing, genomic rearrangements, spontaneous mutations and epigenetic mechanisms such as differential methylation. Most examples of phenotypic variation or phase variation have been described in the context of host-pathogen interactions as mechanisms allowing pathogens to evade host immune responses. Recent reports indicate that phase variation is also relevant in competitive root colonization and biological control of phytopathogens. Many rhizospere Pseudomonas species show phenotypic variation, based on spontaneous mutation of the gacA and gacS genes. These morphological variants do not express secondary metabolites and have improved growth characteristics. The latter could contribute to efficient root colonization and success in competition, especially since (as shown for one strain) these variants were observed to revert to their wild-type form. The observation that these variants are present in rhizosphere-competent Pseudomonas bacteria suggests the existence of a conserved strategy to increase their success in the rhizosphere.
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Affiliation(s)
- Daan van den Broek
- Leiden University, Institute of Biology, Clusius Laboratory, Wassenaarseweg 64, 2333 AL Leiden, the Netherlands.
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9
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Dooley H, Flajnik MF. Antibody repertoire development in cartilaginous fish. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2006; 30:43-56. [PMID: 16146649 DOI: 10.1016/j.dci.2005.06.022] [Citation(s) in RCA: 127] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
There are 3 H chain and 3 L chain isotypes in the cartilaginous fish, all encoded by genes in the so-called cluster (VDDJ, VJ) organization. The H chain isotypes IgM and IgNAR, are readily detected at the protein level in most species. The third is readily identified at the protein level in skates (IgR) but only via immunoprecipitation or at the transcript level in sharks (IgW). High levels of diversity in CDR3 and up to 200 germline genes have been detected for IgM depending upon the species examined. IgNAR displays very high levels of CDR3 diversity but almost none in the germline. At least IgNAR and L chain genes have been shown to hypermutate to very high levels, apparently in response to antigen. The mutation footprints are similar to those in mammals except that the shark genes uniquely mutate nucleotide residues in tandem. A conspicuous feature of cartilaginous fish Ig genes is the presence of germline-joined genes, which are a result of RAG activity in germ cells. Such genes are expressed early in ontogeny and then extinguished or expressed at lower levels. 19S IgM and IgW expression precede that of 7S IgM and IgNAR during ontogeny. The 'switch' from 19S to 7S IgM, the regulation of expression of the Ig clusters, and the microenvironments for mutation/selection of cartilaginous fish B cells are all areas of ongoing research.
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Affiliation(s)
- H Dooley
- Department of Microbiology and Immunology, University of Maryland School of Medicine, 655 West Baltimore Street, Baltimore, MD 21201, USA
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Wallace R, Wallace RG. Adaptive chronic infection, structured stress, and medical magic bullets: do reductionist cures select for holistic diseases? Biosystems 2005; 77:93-108. [PMID: 15527949 DOI: 10.1016/j.biosystems.2004.04.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2004] [Revised: 04/21/2004] [Accepted: 04/28/2004] [Indexed: 11/24/2022]
Abstract
With a generalized language-of-thought argument for immune cognition, we model how population-directed, structured, psychosocial stress can impose an image of itself on the coevolutionary conflict between a highly adaptive chronic infection and the immune response. As population-level structured stress appears a fundamental part of the biology of disease, we raise the possibility that simplistic individual-oriented magic-bullet drug treatments, vaccines, and risk-reduction programs that do not address the fundamental living and working conditions which underlie disease ecology will fail to control many current epidemics. In addition, such reductionist interventions may go so far as to select for more holistic pathogens characterized by processes operating at multiple levels of biocultural organization. The complications are representative of the concerns of cultural immunology, a new field of study.
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Wilson TM, Vaisman A, Martomo SA, Sullivan P, Lan L, Hanaoka F, Yasui A, Woodgate R, Gearhart PJ. MSH2-MSH6 stimulates DNA polymerase eta, suggesting a role for A:T mutations in antibody genes. ACTA ACUST UNITED AC 2005; 201:637-45. [PMID: 15710654 PMCID: PMC2213055 DOI: 10.1084/jem.20042066] [Citation(s) in RCA: 150] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Activation-induced cytidine deaminase deaminates cytosine to uracil (dU) in DNA, which leads to mutations at C:G basepairs in immunoglobulin genes during somatic hypermutation. The mechanism that generates mutations at A:T basepairs, however, remains unclear. It appears to require the MSH2–MSH6 mismatch repair heterodimer and DNA polymerase (pol) η, as mutations of A:T are decreased in mice and humans lacking these proteins. Here, we demonstrate that these proteins interact physically and functionally. First, we show that MSH2–MSH6 binds to a U:G mismatch but not to other DNA intermediates produced during base excision repair of dUs, including an abasic site and a deoxyribose phosphate group. Second, MSH2 binds to pol η in solution, and endogenous MSH2 associates with the pol in cell extracts. Third, MSH2–MSH6 stimulates the catalytic activity of pol η in vitro. These observations suggest that the interaction between MSH2–MSH6 and DNA pol η stimulates synthesis of mutations at bases located downstream of the initial dU lesion, including A:T pairs.
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Affiliation(s)
- Teresa M Wilson
- Radiation Oncology Research Laboratory, Department of Radiation Oncology, University of Maryland, Baltimore, MD 21201, USA
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12
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Rawstron A, Hillmen P, Houlston R. Clonal lymphocytes in persons without known chronic lymphocytic leukemia (CLL): implications of recent findings in family members of CLL patients. Semin Hematol 2005; 41:192-200. [PMID: 15269879 DOI: 10.1053/j.seminhematol.2004.05.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Several genetic abnormalities have been characterized in chronic lymphocytic leukemia (CLL) but these are predominantly secondary events and the initiating phenomena in the etiology of the disease are yet to be established. Studies of inherited susceptibility have identified the early oncogenic events in both familial and "sporadic" forms of several malignant disorders, and this may also be possible in CLL. However, the utility of linkage analysis in identifying a predisposition locus for the disease is limited because large multigenerational families segregating CLL are rare, while the more frequent small nuclear CLL families contain insufficient numbers of affected individuals. The power to detect predisposition gene(s) could be greatly increased by extending the number of affected individuals within a particular family, for example, by identifying family members with subclinical levels of disease. High-sensitivity flow cytometry techniques, developed to monitor disease in CLL patients undergoing treatment, have allowed accurate enumeration of subclinical levels of CLL cells in healthy individuals from the general population and CLL families. Emerging evidence confirms the phenotypic, genotypic, and clinical associations between the aberrant cells in healthy individuals and those in CLL patients. The data suggest that inherited factors increase the susceptibility to both indolent and aggressive CLL, and they provide unbiased demonstration that the age of onset in CLL families is younger than in the general population.
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13
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Kivisaar M. Stationary phase mutagenesis: mechanisms that accelerate adaptation of microbial populations under environmental stress. Environ Microbiol 2004; 5:814-27. [PMID: 14510835 DOI: 10.1046/j.1462-2920.2003.00488.x] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Microorganisms are exposed to constantly changing environmental conditions. In a growth-restricting environment (e.g. during starvation), mutants arise that are able to take over the population by a process known as stationary phase mutation. Genetic adaptation of a microbial population under environmental stress involves mechanisms that lead to an elevated mutation rate. Under stressful conditions, DNA synthesis may become more erroneous because of the induction of error-prone DNA polymerases, resulting in a situation in which DNA repair systems are unable to cope with increasing amounts of DNA lesions. Transposition may also increase genetic variation. One may ask whether the rate of mutation under stressful conditions is elevated as a result of malfunctioning of systems responsible for accuracy or are there specific mechanisms that regulate the rate of mutations under stress. Evidence for the presence of mutagenic pathways that have probably been evolved to control the mutation rate in a cell will be discussed.
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Affiliation(s)
- Maia Kivisaar
- Department of Genetics, Institute of Molecular and Cell Biology, Tartu University and Estonian Biocentre, 51010 Tartu, Estonia.
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14
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Resnick MA, Inga A. Functional mutants of the sequence-specific transcription factor p53 and implications for master genes of diversity. Proc Natl Acad Sci U S A 2003; 100:9934-9. [PMID: 12909720 PMCID: PMC187891 DOI: 10.1073/pnas.1633803100] [Citation(s) in RCA: 129] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2003] [Indexed: 12/17/2022] Open
Abstract
There are many sources of genetic diversity, ranging from programmed mutagenesis in antibody genes to random mutagenesis during species evolution or development of cancer. We propose that mutations in DNA sequence-specific transcription factors that target response elements (REs) in many genes can also provide for rapid and broad phenotypic diversity, if the mutations lead to altered binding affinities at individual REs. To test this concept, we examined the in vivo transactivation capacity of wild-type human and murine p53 and 25 partial function mutants. The p53s were expressed in yeast from a rheostatable promoter, and the transactivation capacities toward >15 promoter REs upstream of a reporter gene were measured. Surprisingly, there was wide variation in transactivation by the mutant p53s toward the various REs. This is the first study to address directly the impact of mutations in a sequence-specific transcription factor on transactivation from a wide array of REs. We propose a master gene hypothesis for phenotypic diversity where the master gene is a single transcriptional activator (or repressor) that regulates many genes through different REs. Mutations of the master gene can lead to a variety of simultaneous changes in both the selection of targets and the extent of transcriptional modulation at the individual targets, resulting in a vast number of potential phenotypes that can be created with minimal mutational changes without altering existing protein-protein interactions.
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Affiliation(s)
- Michael A Resnick
- Laboratory of Molecular Genetics, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA.
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15
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McDonald JP, Frank EG, Plosky BS, Rogozin IB, Masutani C, Hanaoka F, Woodgate R, Gearhart PJ. 129-derived strains of mice are deficient in DNA polymerase iota and have normal immunoglobulin hypermutation. J Exp Med 2003; 198:635-43. [PMID: 12925679 PMCID: PMC2194173 DOI: 10.1084/jem.20030767] [Citation(s) in RCA: 148] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Recent studies suggest that DNA polymerase eta (poleta) and DNA polymerase iota (poliota) are involved in somatic hypermutation of immunoglobulin variable genes. To test the role of poliota in generating mutations in an animal model, we first characterized the biochemical properties of murine poliota. Like its human counterpart, murine poliota is extremely error-prone when catalyzing synthesis on a variety of DNA templates in vitro. Interestingly, when filling in a 1 base-pair gap, DNA synthesis and subsequent strand displacement was greatest in the presence of both pols iota and eta. Genomic sequence analysis of Poli led to the serendipitous discovery that 129-derived strains of mice have a nonsense codon mutation in exon 2 that abrogates production of poliota. Analysis of hypermutation in variable genes from 129/SvJ (Poli-/-) and C57BL/6J (Poli+/+) mice revealed that the overall frequency and spectrum of mutation were normal in poliota-deficient mice. Thus, either poliota does not participate in hypermutation, or its role is nonessential and can be readily assumed by another low-fidelity polymerase.
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Affiliation(s)
- John P McDonald
- Laboratory of Genomic Integrity, Building 6, Room 1A13, NICHD, NIH, 9000 Rockville Pike, Bethesda, MD 20892-2725, USA.
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Sohail A, Klapacz J, Samaranayake M, Ullah A, Bhagwat AS. Human activation-induced cytidine deaminase causes transcription-dependent, strand-biased C to U deaminations. Nucleic Acids Res 2003; 31:2990-4. [PMID: 12799424 PMCID: PMC162340 DOI: 10.1093/nar/gkg464] [Citation(s) in RCA: 222] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Activation-induced cytidine deaminase (AID) is required for the maturation of antibodies in higher vertebrates, where it promotes somatic hypermutation (SHM), class switch recombination and gene conversion. While it is known that SHM requires high levels of transcription of the target genes, it is unclear whether this is because AID targets transcribed genes. We show here that the human AID promotes C to T mutations in Escherichia coli which are stimulated by transcription. The mutations are strand-biased and occur preferentially in the non-transcribed strand of the target gene. Human AID purified from E.coli is active without prior treatment with a ribonuclease and deaminates cytosines in plasmid DNA in vitro. Further, the action of this enzyme is greatly stimulated by the transcription of the target gene in a strand-dependent fashion. These results confirm the prediction that AID may act directly on DNA and show that it can act on transcribing DNA in the absence of specialized DNA structures such as R-loops. It suggests that AID may be recruited to variable genes through transcription without the assistance of other proteins and that the strand bias in SHM may be caused by the preference of AID for the non-transcribed strand.
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Affiliation(s)
- Anjum Sohail
- Department of Chemistry, Wayne State University, Detroit, MI 48202, USA
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Boursier L, Su W, Spencer J. Imprint of somatic hypermutation differs in human immunoglobulin heavy and lambda chain variable gene segments. Mol Immunol 2003; 39:1025-34. [PMID: 12749909 DOI: 10.1016/s0161-5890(03)00033-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Somatic hypermutation (SHM) introduces mutations into immunoglobulin (Ig) variable gene segments, thus diversifying the B cell repertoire prior to positive selection of high affinity variants during maturation of T cell-dependent B cell responses. Somatic hypermutation of Ig heavy chain generates predominantly single base substitutions, favoring transition rather than transversion substitutions, and tends to direct mutations to specific 4-mer target sequences with G in second and C in third position. Here we have analyzed heavily mutated, nonproductively rearranged Ig lambda chain variable gene segments from human intestinal plasma cells, controlling for germline composition of the genes and local sequence variability. We have observed significant G.C strand bias in IgV(lambda), and differences in some di- and trinuleotide target preferences in IgV(lambda) compared to IgV(H). There is also a significant tendency to accumulate adjacent triplet mutations in IgV(lambda), which is not evident in IgV(H) in normal circumstances. These observations suggest that some aspect of the mechanism of somatic hypermutation operates differently in human immunoglobulin heavy and lambda light chain variable gene segments.
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Affiliation(s)
- Laurent Boursier
- Department of Histopathology, Guy's, King's and St Thomas' Medical School, St Thomas' Campus, Lambeth Palace Road, London, SE1 7EH, UK.
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