1
|
Waindok P, Janecek-Erfurth E, Lindenwald DL, Wilk E, Schughart K, Geffers R, Strube C. Toxocara canis- and Toxocara cati-Induced Neurotoxocarosis Is Associated with Comprehensive Brain Transcriptomic Alterations. Microorganisms 2022; 10:microorganisms10010177. [PMID: 35056627 PMCID: PMC8779660 DOI: 10.3390/microorganisms10010177] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 01/10/2022] [Accepted: 01/11/2022] [Indexed: 12/27/2022] Open
Abstract
Toxocara canis and Toxocara cati are globally occurring zoonotic roundworms of dogs and cats. Migration and persistence of Toxocara larvae in the central nervous system of paratenic hosts including humans may cause clinical signs of neurotoxocarosis (NT). As pathomechanisms of NT and host responses against Toxocara larvae are mostly unknown, whole-genome microarray transcription analysis was performed in cerebra and cerebella of experimentally infected C57Bl/6J mice as paratenic host model at days 14, 28, 70, 98, and 120 post-infection. Neuroinvasion of T. cati evoked 220 cerebral and 215 cerebellar differentially transcribed genes (DTGs), but no particular PANTHER (Protein ANalysis THrough Evolutionary Relationships) pathway was affected. In T. canis-infected mice, 1039 cerebral and 2073 cerebellar DTGs were identified. Statistically significant dysregulations occurred in various pathways, including cholesterol biosynthesis, apoptosis signaling, and the Slit/Robo mediated axon guidance as well as different pathways associated with the immune and defense response. Observed dysregulations of the cholesterol biosynthesis, as well as the Alzheimer disease-amyloid secretase pathway in conjunction with previous histopathological neurodegenerative findings, may promote the discussion of T. canis as a causative agent for dementia and/or Alzheimer’s disease. Furthermore, results contribute to a deeper understanding of the largely unknown pathogenesis and host-parasite interactions during NT, and may provide the basis for prospective investigations evaluating pathogenic mechanisms or designing novel diagnostic and therapeutic approaches.
Collapse
Affiliation(s)
- Patrick Waindok
- Institute for Parasitology, Centre for Infection Medicine, University of Veterinary Medicine Hannover, 30559 Hanover, Germany; (P.W.); (E.J.-E.); (D.L.L.)
| | - Elisabeth Janecek-Erfurth
- Institute for Parasitology, Centre for Infection Medicine, University of Veterinary Medicine Hannover, 30559 Hanover, Germany; (P.W.); (E.J.-E.); (D.L.L.)
| | - Dimitri L. Lindenwald
- Institute for Parasitology, Centre for Infection Medicine, University of Veterinary Medicine Hannover, 30559 Hanover, Germany; (P.W.); (E.J.-E.); (D.L.L.)
| | - Esther Wilk
- Department of Infection Genetics, Helmholtz Centre for Infection Research, 38124 Braunschweig, Germany; (E.W.); (K.S.)
| | - Klaus Schughart
- Department of Infection Genetics, Helmholtz Centre for Infection Research, 38124 Braunschweig, Germany; (E.W.); (K.S.)
- Department of Microbiology, Immunology and Biochemistry, University of Tennessee Health Science Centre, Memphis, TN 38163, USA
- Institute for Animal Breeding and Genetics, University of Veterinary Medicine Hannover, 30559 Hanover, Germany
| | - Robert Geffers
- Research Group Genome Analytics, Helmholtz Centre for Infection Research, 38124 Braunschweig, Germany;
| | - Christina Strube
- Institute for Parasitology, Centre for Infection Medicine, University of Veterinary Medicine Hannover, 30559 Hanover, Germany; (P.W.); (E.J.-E.); (D.L.L.)
- Correspondence: ; Tel.: +49-511-953-8711
| |
Collapse
|
2
|
Wu X, You W, Wu Z, Ye F, Chen S. Serum biomarker analysis at the protein level on pulmonary hypertension secondary to old anterior myocardial infarction. Pulm Circ 2020; 10:2045894020969079. [PMID: 33282196 PMCID: PMC7691928 DOI: 10.1177/2045894020969079] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Accepted: 10/06/2020] [Indexed: 01/06/2023] Open
Abstract
Pulmonary hypertension (PH) related to old anterior myocardial infarction (OAMI)
always accompanies a bad prognosis, and thus, we aimed to screen serum
biomarkers related to PH in OAMI patients. According to right ventricular
systolic pressure, we divided mice into sham, OAMI, and PH-OAMI groups and
evaluated body, heart and lung weight, heart function, pulmonary blood flow
velocity, cardiac fibrotic area, and pulmonary arteriole condition. Lung and
serum were under the proteomic analysis. Levels of three identified proteins
were measured. Compared with sham and OAMI mice, PH-OAMI mice showed heart
dysfunction, low pulmonary blood flow, high right ventricular systolic pressure,
heavy heart and lung weight, large cardiac fibrotic area, and pathological
pulmonary arteriole remodeling (P<0.05 or
P<0.01). Haptoglobin, annexin A5, and Ig mu chain C region
of lung and serum were changed significantly in PH-OAMI mice
(P<0.01). Then, we collected serum and clinical data,
measured three serum protein levels, and performed multivariate regression and
receiver operating characteristic curve in patients (normal, OAMI, and PH-OAMI
groups). Compared with normal and OAMI patients, serum levels of three proteins
in PH-OAMI patients were also altered notably (P<0.01).
These three proteins can predict PH in OAMI patients
(P<0.01). Receiver operating characteristic curve analysis
revealed haptoglobin (cut-off value: 78.295, sensitivity: 62.8%, specificity:
94.4%), annexin A5 (cut-off value: 151.925, sensitivity: 41.9%, specificity:
82.4%), and Ig mu chain C region (cut-off value: 168.885, sensitivity: 86.0%,
specificity: 79.6%) (P<0.01). Three circulating serum
proteins can be useful for the categorization of OAMI patients with and without
PH.
Collapse
Affiliation(s)
- Xiangqi Wu
- Division of Cardiology, Nanjing First Hospital, Nanjing Medical University, Nanjing, China
| | - Wei You
- Division of Cardiology, Nanjing First Hospital, Nanjing Medical University, Nanjing, China
| | - Zhiming Wu
- Division of Cardiology, Nanjing First Hospital, Nanjing Medical University, Nanjing, China
| | - Fei Ye
- Division of Cardiology, Nanjing First Hospital, Nanjing Medical University, Nanjing, China
| | - Shaoliang Chen
- Division of Cardiology, Nanjing First Hospital, Nanjing Medical University, Nanjing, China
| |
Collapse
|
3
|
Pantophlet R, Trattnig N, Murrell S, Lu N, Chau D, Rempel C, Wilson IA, Kosma P. Bacterially derived synthetic mimetics of mammalian oligomannose prime antibody responses that neutralize HIV infectivity. Nat Commun 2017; 8:1601. [PMID: 29150603 PMCID: PMC5693931 DOI: 10.1038/s41467-017-01640-y] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2017] [Accepted: 10/04/2017] [Indexed: 12/21/2022] Open
Abstract
Oligomannose-type glycans are among the major targets on the gp120 component of the HIV envelope protein (Env) for broadly neutralizing antibodies (bnAbs). However, attempts to elicit oligomannose-specific nAbs by immunizing with natural or synthetic oligomannose have so far not been successful, possibly due to B cell tolerance checkpoints. Here we design and synthesize oligomannose mimetics, based on the unique chemical structure of a recently identified bacterial lipooligosaccharide, to appear foreign to the immune system. One of these mimetics is bound avidly by members of a family of oligomannose-specific bnAbs and their putative common germline precursor when presented as a glycoconjugate. The crystal structure of one of the mimetics bound to a member of this bnAb family confirms the antigenic resemblance. Lastly, immunization of human-antibody transgenic animals with a lead mimetic evokes nAbs with specificities approaching those of existing bnAbs. These results provide evidence for utilizing antigenic mimicry to elicit oligomannose-specific bnAbs to HIV-1.
Collapse
Affiliation(s)
- Ralph Pantophlet
- Faculty of Health Sciences, Simon Fraser University, Burnaby, BC, Canada, V5A1S6. .,Department of Molecular Biology & Biochemistry, Simon Fraser University, Burnaby, BC, Canada, V5A1S6. .,SFU Interdisciplinary Research Centre for HIV, Simon Fraser University, Burnaby, BC, Canada, V5A1S6.
| | - Nino Trattnig
- Department of Chemistry, University of Natural Resources and Life Sciences, A-1190, Vienna, Austria
| | - Sasha Murrell
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA, 92037, USA.,Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, CA, 92037, USA
| | - Naiomi Lu
- Faculty of Health Sciences, Simon Fraser University, Burnaby, BC, Canada, V5A1S6
| | - Dennis Chau
- Faculty of Health Sciences, Simon Fraser University, Burnaby, BC, Canada, V5A1S6
| | - Caitlin Rempel
- Faculty of Health Sciences, Simon Fraser University, Burnaby, BC, Canada, V5A1S6
| | - Ian A Wilson
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA, 92037, USA. .,Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, CA, 92037, USA. .,IAVI Neutralizing Antibody Center, The Scripps Research Institute, La Jolla, CA, 92037, USA. .,Center for HIV/AIDS Vaccine Immunology and Immunogen Discovery, The Scripps Research Institute, La Jolla, CA, 92037, USA.
| | - Paul Kosma
- Department of Chemistry, University of Natural Resources and Life Sciences, A-1190, Vienna, Austria.
| |
Collapse
|
4
|
Mallikaratchy PR, Ruggiero A, Gardner JR, Kuryavyi V, Maguire WF, Heaney ML, McDevitt MR, Patel DJ, Scheinberg DA. A multivalent DNA aptamer specific for the B-cell receptor on human lymphoma and leukemia. Nucleic Acids Res 2010; 39:2458-69. [PMID: 21030439 PMCID: PMC3064813 DOI: 10.1093/nar/gkq996] [Citation(s) in RCA: 142] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Long-term survival still eludes most patients with leukemia and non-Hodgkin’s lymphoma. No approved therapies target the hallmark of the B cell, its mIgM, also known as the B-cell receptor (BCR). Aptamers are small oligonucleotides that can specifically bind to a wide range of target molecules and offer some advantages over antibodies as therapeutic agents. Here, we report the rational engineering of aptamer TD05 into multimeric forms reactive with the BCR that may be useful in biomedical applications. Systematic truncation of TD05 coupled with modification with locked nucleic acids (LNA) increased conformational stability and nuclease resistance. Trimeric and tetrameric versions with optimized polyethyleneglycol (PEG) linker lengths exhibited high avidity at physiological temperatures both in vitro and in vivo. Competition and protease studies showed that the multimeric, optimized aptamer bound to membrane-associated human mIgM, but not with soluble IgM in plasma, allowing the possibility of targeting leukemias and lymphomas in vivo. The B-cell specificity of the multivalent aptamer was confirmed on lymphoma cell lines and fresh clinical leukemia samples. The chemically engineered aptamers, with significantly improved kinetic and biochemical features, unique specificity and desirable pharmacological properties, may be useful in biomedical applications.
Collapse
|
5
|
Marchalonis JJ, Schluter SF, Bernstein RM, Shen S, Edmundson AB. Phylogenetic emergence and molecular evolution of the immunoglobulin family. Adv Immunol 1998; 70:417-506. [PMID: 9755343 DOI: 10.1016/s0065-2776(08)60392-2] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- J J Marchalonis
- Department of Microbiology and Immunology, College of Medicine, University of Arizona, Tucson 85724, USA
| | | | | | | | | |
Collapse
|
6
|
Yel L, Minegishi Y, Coustan-Smith E, Buckley RH, Trübel H, Pachman LM, Kitchingman GR, Campana D, Rohrer J, Conley ME. Mutations in the mu heavy-chain gene in patients with agammaglobulinemia. N Engl J Med 1996; 335:1486-93. [PMID: 8890099 DOI: 10.1056/nejm199611143352003] [Citation(s) in RCA: 193] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
BACKGROUND Most patients with congenital hypogammaglobulinemia and absent B cells are males with X-linked agammaglobulinemia, which is caused by mutations in the gene for Bruton's tyrosine kinase (Btk); however, there are females with a similar disorder who do not have mutations in this gene. We studied two families with autosomal recessive defects in B-cell development and patients with presumed X-linked agammaglobulinemia who did not have mutations in Btk. METHODS A series of candidate genes that encode proteins involved in B-cell signal-transduction pathways were analyzed by linkage studies and mutation screening. RESULTS Four different mutations were identified in the mu heavy-chain gene on chromosome 14. In one family, there was a homozygous 75-to-100-kb deletion that included D-region genes, J-region genes, and the mu constant-region gene. In a second family, there was a homozygous base-pair substitution in the alternative splice site of the mu heavy-chain gene. This mutation would inhibit production of the membrane form of the mu chain and produce an amino acid substitution in the secreted form. In addition, a patient previously thought to have X-linked agammaglobulinemia was found to have an amino acid substitution on one chromosome at an invariant cysteine that is required for the intrachain disulfide bond and, on the other chromosome, a large deletion that included the immunoglobulin locus. CONCLUSIONS Defects in the mu heavy-chain gene are a cause of agammaglobulinemia in humans. This implies that an intact membrane-bound mu chain is essential for B-cell development.
Collapse
Affiliation(s)
- L Yel
- Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|
7
|
Wilson MR, Ross DA, Miller NW, Clem LW, Middleton DL, Warr GW. Alternate pre-mRNA processing pathways in the production of membrane IgM heavy chains in holostean fish. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 1995; 19:165-177. [PMID: 7556803 DOI: 10.1016/0145-305x(94)00064-m] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
A single gene encodes two forms of the IgM heavy chain (mu) in vertebrates: one (microseconds) present in serum as secreted IgM and the other (microns) as the antigen receptor form of IgM present on the B-lymphocyte membrane. The mRNAs encoding microseconds and microns are derived from a single primary transcript by alternate pathways of RNA processing. In all vertebrates so far examined, with the exception of teleosts, microns mRNA is produced by splicing the transmembrane (TM) encoding exon 1 into a cryptic donor site near the 3' end of the C mu 4 exon. In contrast, teleost species splice the TM exon 1 into the regular splice donor site at the 3' boundary of the C mu 3 exon. We have examined micron mRNAs in two species of primitive bony fish, the holostean bowfin and the longnose gar. These fish utilize both the C mu 3 to TM1 (teleost) pathway and the typical cryptic C mu 4 to TM1 pathway. In addition the bowfin possesses a cryptic splice donor site near the middle of C mu 3. This is used in the production of a third species of microns-encoding mRNA, but does not participate in the production of an alternate form of the microseconds mRNA. The structure and patterns of expression of their mu genes suggest that the gar and bowfin may be more closely related than implied by the current view of fish evolution.
Collapse
Affiliation(s)
- M R Wilson
- Department of Microbiology, University of Mississippi Medical Center, Jackson 39216-4505, USA
| | | | | | | | | | | |
Collapse
|
8
|
Mariette X, Brouet JC, Danon F, Tsapis A, Lassoued K. Nucleotide sequence analysis of the VL and VH domains of five human IgM directed to lamin B. Evidence for an antigen-driven process in the generation of human autoantibodies to lamin B. ARTHRITIS AND RHEUMATISM 1993; 36:1315-24. [PMID: 8216425 DOI: 10.1002/art.1780360916] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
OBJECTIVE To gain insight into the genetic origin of human antilamin autoantibodies, we determined the nucleotide sequence of the light and heavy chain variable region (VL and VH) domains of 5 IgM antibodies directed to lamin B. These antibodies represent a distinct subset of antinuclear antibodies, and their presence is associated with a particular lupus-like syndrome. METHODS We derived and cloned lymphoblastoid cell lines from peripheral blood B cells of 3 patients, selected anti-lamin B-producing subclones, and sequenced the messenger RNA coding for Ig heavy and light chains. RESULTS We isolated 2 subclones (1 IgM kappa, 1 IgM lambda) from one patient (FUR) and 2 subclones (both IgM lambda) from another (HER). In contrast, all 8 lines derived from B cells isolated from the third patient (BEN) synthesized identical anti-lamin B IgM kappa antibodies: All VL and VH domains from these 5 IgM were encoded by different VL or VH genes. DH regions were all different, and there was no restriction in the use of JL or JH segments. Analysis of the nucleotide sequence of the VL domains allowed the identification of the putative germinal gene in 3 instances (V kappa IV, Humkv325, and V lambda III.1); the overall ratios of replacement:silent mutations (R:S) were 6.5 and 1.2 in the complementarity-determining regions (CDRs) and framework regions (FRs), respectively. The 2 other lambda sequences belonged to the V lambda III family. With regard to VH domains, 3 of 5 derived from previously identified germline genes (VHIV 4.19, VHIV 4.22, and VHIII 9.1); the overall R:S ratio for these genes was 8 and 1.5 in CDRs and FRs, respectively. CONCLUSION Taken together, these data provide evidence that the repertoire of human antilamin autoantibodies is not restricted and that the antigen (or another kind of selective pressure) plays a role in the generation of autoantibodies to lamin B. This hypothesis is in accordance with the reactivity of these antibodies to discrete epitopes of lamin B.
Collapse
Affiliation(s)
- X Mariette
- Laboratory of Immunopathology, Hôpital Saint-Louis, Paris, France
| | | | | | | | | |
Collapse
|
9
|
Corradini P, Boccadoro M, Voena C, Pileri A. Evidence for a bone marrow B cell transcribing malignant plasma cell VDJ joined to C mu sequence in immunoglobulin (IgG)- and IgA-secreting multiple myelomas. J Exp Med 1993; 178:1091-6. [PMID: 8350048 PMCID: PMC2191156 DOI: 10.1084/jem.178.3.1091] [Citation(s) in RCA: 88] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Multiple myeloma is a B cell malignancy characterized by the expansion of plasma cells producing monoclonal immunoglobulins (Ig). It has been regarded as a tumor arising at the B, pre-B lymphocyte, or even stem cell level. Precursor cells are presumed to proliferate and differentiate giving rise to the plasma cell clonal expansion. Antigenic features and specific Ig gene rearrangement shared by B lymphocytes and myeloma cells have supported this hypothesis. However, the existence of such a precursor is based upon indirect evidence and is still an open question. During differentiation, B cells rearrange variable (V) regions of Ig heavy chain genes, providing a specific marker of clonality. Using an anchor polymerase chain reaction assay, these rearranged regions from five patients with multiple myeloma were cloned and sequenced. The switch of the Ig constant (C) region was used to define the B cell differentiation stage: V regions are linked to C mu genes in pre-B and B lymphocytes (pre-switch B cells), but to C gamma or C alpha in post-switch B lymphocytes and plasma cells (post-switch B cells). Analysis of bone marrow cells at diagnosis revealed the presence of pre-switch B cells bearing plasma cell V regions still joined to the C mu gene. These cells were not identified in peripheral blood, where tumor post-switch B cells were detected. These pre-switch B cells may be regarded as potential myeloma cell precursors.
Collapse
Affiliation(s)
- P Corradini
- Divisione di Ematologia dell' Università di Torino, Ospedale Molinette, Italy
| | | | | | | |
Collapse
|
10
|
Harindranath N, Donadel G, Sigounas G, Notkins AL. Comparison of complete nucleotide sequence of the human IgM heavy chain constant region of polyreactive and monoreactive antibodies. Mol Immunol 1993; 30:111-2. [PMID: 8417370 DOI: 10.1016/0161-5890(93)90434-d] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Affiliation(s)
- N Harindranath
- Laboratory of Oral Medicine, National Institute of Dental Research, National Institutes of Health, Bethesda, MD 20892
| | | | | | | |
Collapse
|
11
|
Tomlinson IM, Walter G, Marks JD, Llewelyn MB, Winter G. The repertoire of human germline VH sequences reveals about fifty groups of VH segments with different hypervariable loops. J Mol Biol 1992; 227:776-98. [PMID: 1404388 DOI: 10.1016/0022-2836(92)90223-7] [Citation(s) in RCA: 486] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
We have used the polymerase chain reaction and VH family-based primers to clone and sequence 74 human germline VH segments from a single individual and built a directory to include all known germline sequences. The directory contains 122 VH segments with different nucleotide sequences, 83 of which have open reading frames. The directory indicates that the structural diversity of the germline repertoire for antigen binding is fixed by about 50 groups of VH segments: each group encodes identical hypervariable loops. The directory should help in mapping the VH locus, in estimating somatic mutation and VH segment usage and in designing and constructing synthetic antibody libraries.
Collapse
|
12
|
Shimizu A, Nussenzweig MC, Han H, Sanchez M, Honjo T. Trans-splicing as a possible molecular mechanism for the multiple isotype expression of the immunoglobulin gene. J Exp Med 1991; 173:1385-93. [PMID: 1903429 PMCID: PMC2190851 DOI: 10.1084/jem.173.6.1385] [Citation(s) in RCA: 61] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
We analyzed the molecular mechanism for the immunoglobulin (Ig) multiple isotype expression using a transgenic mouse (TG.SA) model system. Though most of the endogenous mu chain expression was excluded by the expression of the human rearranged mu transgene in the TG.SA mouse, a significant portion of splenic B lymphocytes could express the transgenic human IgM and endogenous mouse IgG simultaneously after stimulation with lipopolysaccharide and interleukin 4. The fluorescence-activated cell sorter-purified population of the human IgM+/mouse IgG+ cells expressed mRNA that consisted of properly spliced sequences of the transgenic VHDJH and the endogenous mouse C gamma genes (trans-mRNA), together with the transgenic human mu mRNA and germline transcripts of the mouse C gamma gene, without apparent rearrangement of the transgene. We also found that a lymphoma tumor, derived from the cross between the TG.SA mouse and another transgenic mouse carrying Ig H chain enhancer-driven c-myc oncogene, expressed about equal levels of the trans-mRNA and the transgenic mu mRNA without DNA rearrangement in either the transgene or the endogenous mouse switch region. These findings strongly support our previous proposal that the trans-splicing can account for the multiple isotype expression in this transgenic model and also suggest that novel molecular mechanism(s) might be involved in this reaction.
Collapse
Affiliation(s)
- A Shimizu
- Center for Molecular Biology and Genetics, Kyoto University Faculty of Medicine, Japan
| | | | | | | | | |
Collapse
|
13
|
Neale GA, Kitchingman GR. mRNA transcripts initiating within the human immunoglobulin mu heavy chain enhancer region contain a non-translatable exon and are extremely heterogeneous at the 5' end. Nucleic Acids Res 1991; 19:2427-33. [PMID: 1904154 PMCID: PMC329453 DOI: 10.1093/nar/19.9.2427] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Transcription events are thought to precede gene rearrangement in the immunoglobulin (Ig) loci and may be the mechanism by which the various gene regions are made accessible for recombination. If this is the case, identification and characterization of transcripts from the Ig loci should permit a better understanding of the gene rearrangement process. We have isolated a 2.3 kb cDNA clone from the human pre-B cell line Nalm-1 that contains enhancer-specific sequences from the Ig heavy (H) chain gene locus. The 2.3 kb transcript initiated within the enhancer region and showed extreme 5' heterogeneity, with more than 50 initiation sites mapping near the Ig-specific octamer ATTTGCGT. Sequencing of the cDNA clone demonstrated that 644 nucleotides from the Ig enhancer region were incorporated as a leader exon spliced to the mu constant (Cmu) region. This leader exon contained many translation termination codons and may function to inhibit the translation of sterile Cmu polypeptides. Using an enhancer-derived probe, we detected two low-abundancy mRNA transcripts with sizes of 2.3 and 12 kb. Northern blot analysis suggested that the 12 kb transcript was the unspliced precursor mRNA of a VDJ rearrangement. The potential role of these enhancer-containing transcripts in the opening of the IgH chain gene for rearrangement and for class switching is discussed.
Collapse
Affiliation(s)
- G A Neale
- Department of Virology and Molecular Biology, St Jude Children's Research Hospital, Memphis, TN 38101
| | | |
Collapse
|