scholarly journals Positive and negative regulation of immunoglobulin gene expression by a novel B-cell-specific enhancer element.

1991 ◽  
Vol 11 (1) ◽  
pp. 75-83 ◽  
Author(s):  
J Wang ◽  
M Oketani ◽  
T Watanabe
Keyword(s):  
T Cells ◽  
B Cells ◽  
B Cell ◽  
Heavy Chain ◽  
Hela Cells ◽  
Simian Virus 40 ◽  
Immunoglobulin Gene ◽  
Enhancer Activity ◽  
Enhancer Element ◽  
Octamer Motif

A new B-cell-specific enhancer element has been identified 3' of E4 and the octamerlike motifs in the human immunoglobulin heavy-chain gene enhancer. Tandem copies of this 67-bp MnlI-AluI fragment, when fused to the chloramphenicol acetyltransferase gene driven by the conalbumin promoter, stimulated transcription in B cells but not in Jurkat T cells or HeLa cells. Footprinting analysis revealed that the identical sequence CCGAAACTGAAAAGG, designated E6, was protected by nuclear extracts from B cells, T cells, or HeLa cells. Gel mobility shift assays using a synthetic E6 motif detected a B-cell-specific complex in addition to a ubiquitous band found also in T cells and HeLa cells. In agreement with the results of gel retardation assays, tandem copies of the E6 motif stimulated transcription in ARH77 and Raji cells but not in Jurkat or HeLa cells. Furthermore, a mutant E6 motif lost both in vitro binding activity and in vivo enhancer activity. In striking contrast to the mouse Ig heavy-chain enhancer, in which the octamer motif acts as a B-cell-specific enhancer element, the human enhancer contains an octamerlike sequence with one base substitution which bound octamer-binding proteins with only very low affinity and showed no enhancer activity of its own. Interestingly, the MnlI-AluI fragment could suppress the basal-level activity of the conalbumin promoter in both Jurkat and HeLa cells. Moreover, simian virus 40 enhancer activity was blocked by the MnlI-AluI fragment in HeLa cells but not in B cells. Thus, the novel enhancer element identified in this study is probably a target site for both positive and negative factors.

Positive and negative regulation of immunoglobulin gene expression by a novel B-cell-specific enhancer element

1991 ◽  
Vol 11 (1) ◽  
pp. 75-83
Author(s):  
J Wang ◽  
M Oketani ◽  
T Watanabe
Keyword(s):  
T Cells ◽  
B Cells ◽  
B Cell ◽  
Heavy Chain ◽  
Hela Cells ◽  
Simian Virus 40 ◽  
Immunoglobulin Gene ◽  
Enhancer Activity ◽  
Enhancer Element ◽  
Octamer Motif

A new B-cell-specific enhancer element has been identified 3' of E4 and the octamerlike motifs in the human immunoglobulin heavy-chain gene enhancer. Tandem copies of this 67-bp MnlI-AluI fragment, when fused to the chloramphenicol acetyltransferase gene driven by the conalbumin promoter, stimulated transcription in B cells but not in Jurkat T cells or HeLa cells. Footprinting analysis revealed that the identical sequence CCGAAACTGAAAAGG, designated E6, was protected by nuclear extracts from B cells, T cells, or HeLa cells. Gel mobility shift assays using a synthetic E6 motif detected a B-cell-specific complex in addition to a ubiquitous band found also in T cells and HeLa cells. In agreement with the results of gel retardation assays, tandem copies of the E6 motif stimulated transcription in ARH77 and Raji cells but not in Jurkat or HeLa cells. Furthermore, a mutant E6 motif lost both in vitro binding activity and in vivo enhancer activity. In striking contrast to the mouse Ig heavy-chain enhancer, in which the octamer motif acts as a B-cell-specific enhancer element, the human enhancer contains an octamerlike sequence with one base substitution which bound octamer-binding proteins with only very low affinity and showed no enhancer activity of its own. Interestingly, the MnlI-AluI fragment could suppress the basal-level activity of the conalbumin promoter in both Jurkat and HeLa cells. Moreover, simian virus 40 enhancer activity was blocked by the MnlI-AluI fragment in HeLa cells but not in B cells. Thus, the novel enhancer element identified in this study is probably a target site for both positive and negative factors.

Pi, a pre-B-cell-specific enhancer element in the immunoglobulin heavy-chain enhancer

1993 ◽  
Vol 13 (10) ◽  
pp. 5957-5969
Author(s):  
T A Libermann ◽  
D Baltimore
Keyword(s):  
B Cell ◽  
Heavy Chain ◽  
Mutational Analysis ◽  
Protein S ◽  
Immunoglobulin Heavy Chain ◽  
Chain Gene ◽  
Cell Stage ◽  
Enhancer Activity ◽  
Enhancer Element ◽  
Light Chain Gene

We have identified a new immunoglobulin heavy-chain enhancer element, designated pi, between the microE2 and microE3 elements. The pi enhancer element is transcriptionally active primarily during early stages of B-cell development but becomes virtually inactive during B-cell maturation at about the stage of immunoglobulin kappa light-chain gene rearrangement. Mutational analysis suggests that the pi element is crucial for immunoglobulin heavy-chain enhancer activity at the pre-B-cell stage but is almost irrelevant for enhancer activity at the mature B-cell or plasma-cell stage. The activity of the pi enhancer element correlates with the presence of an apparently pre-B-cell-specific protein-DNA complex. The similarity of the pi site to recognition sequences for members of the ets gene family suggests that the protein(s) interacting with the pi site most likely are ets-related transcription factors.

scholarly journals T cell regulation of IgG subclass antibody production in response to T-independent antigens.

1981 ◽  
Vol 153 (1) ◽  
pp. 1-12 ◽  
Author(s):  
P K Mongini ◽  
K E Stein ◽  
W E Paul
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cells ◽  
B Cell ◽  
Heavy Chain ◽  
Chain Gene ◽  
Cell Clones ◽  
T Cell Regulation ◽  
The Difference

The effect of T lymphocytes on the IgM, IgG3, IgG1, IgG2b, and IgG2a responses of B lymphocytes to the type-2 T-independent antigens, trinitrophenylated (TNP)-Ficoll, and TNP-Levan, was investigated. T cell-bearing nu/+ mice were found to produce substantially higher IgG2 serum anti-TNP antibody than their athymic counterparts, and nu/nu and nu/+ IgG2a titers exhibiting more disparity than nu/nu and nu/+ IgG2b titers. The Igm, IgG3, and IgG1 anti-TNP levels in nu/nu and nu/+ mice were indistinguishable. By cell transfer experiments, it was determined that this variance in nude and heterozygote IgG2 responses could not be explained by B cell differences between the two strains or by suppressive effects on IgG2 production within nu/nu mice. Rather, the difference was shown to be the result of the absence of T cells at the time B cells were responding to antigen. In the absence of T cells, the strength of the nu/nu anti-TNP antibody response was found to be in the following order: IgM > IgG3 > IgG1 > IgG2b > IgG2a, a heirarchy identical with the recently proposed heavy chain gene order. The possibilities that T cells influence IgG2 production via their specific recognition of IgG2-bearing B cells or via signals to increase heavy chain switching of responding B cell clones are discussed.

scholarly journals A Mouse with a Monoclonal Primary lmmunoglobulin Repertoire not Further Diversified by V-Gene Replacement

1999 ◽  
Vol 7 (1) ◽  
pp. 43-50 ◽  
Author(s):  
Marilia Cascalho ◽  
Denise A. Martin ◽  
Jamie Wong ◽  
Queenie Lam ◽  
Matthias Wabl ◽  
...  
Keyword(s):  
T Cells ◽  
B Cells ◽  
B Cell ◽  
Heavy Chain ◽  
Light Chain ◽  
Gene Replacement ◽  
Genes Encoding ◽  
V Gene ◽  
Immunoglobulin Repertoire ◽  
Or Gene

We have generated a monoclonal B-cell mouse by introducing homozygous, nonfunctional RAG-2 alleles and aλ1 light-chain transgene into the quasi-monoclonal (QM) mouse, which contains a “knocked-in” VHDJHrearrangement. Thus, this mouse, which we call MonoB, is devoid of T cells and contains preformed heavy- and light-chain genes encoding immunoglobulin with an anti-NP specificity. The MonoB mouse allows us to examine immunoglobulin diversity in the absence of processes mediated by V(D)J recombination and T cells. Here we report that not only is the MonoB's primary immunoglobulin repertoire monoclonal, but also that its secondary repertoire is not further diversified by V-gene replacement or gene conversion. Among 99 heavy-chain and 41λlight-chain genes from peripheral B cells of the MonoB mouse, there were no V-gene replacements. When compared to the QM mouse, which has RAG activity, and for which V-gene replacement is the major diversifying mechanism, these data suggest that V-gene replacement is mediated by V(D)J recombination and not by other recombination systems.

B-cell control region at the 5' end of a major histocompatibility complex class II gene: sequences and factors

1988 ◽  
Vol 8 (10) ◽  
pp. 3975-3987
Author(s):  
A Dorn ◽  
H J Fehling ◽  
W Koch ◽  
M Le Meur ◽  
P Gerlinger ◽  
...  
Keyword(s):  
Major Histocompatibility Complex ◽  
B Cells ◽  
Major Histocompatibility Complex Class ◽  
B Cell ◽  
Simian Virus 40 ◽  
Class Ii ◽  
Immunoglobulin Gene ◽  
Complex Class ◽  
Major Histocompatibility ◽  
Histocompatibility Complex

Transcription of major histocompatibility complex class II genes is elaborately regulated. Mouse class II genes are transcribed primarily in B cells, peripheral macrophages and interdigitating cells, and thymic cortical and medullary cells. In this study, we began to identify the DNA sequences and protein factors that control expression of a class II gene in B cells, addressing in particular how closely they resemble those that regulate immunoglobulin gene expression. We describe a region upstream of the E alpha gene that is crucial for its transcription in the B cells of transgenic mice but is less important in cultured B-cell lines. The sequence of this region reveals several familiar motifs, including a second X-Y pair reminiscent of that residing in the promoter-proximal region of all class II genes, a B motif strikingly homologous to that associated with the immunoglobulin kappa gene enhancer, several Ephrussi motifs, and a Pu box-like sequence very similar to that implicated in simian virus 40 and lymphotrophic papovavirus expression in B cells. Careful study of the proteins that bind specifically to these different motifs prompts us to suggest that major histocompatibility complex class II and immunoglobulin genes rely on quite different factors to achieve B-cell-specific expression.

scholarly journals Bruton's Tyrosine Kinase Regulates Immunoglobulin Promoter Activation in Association with the Transcription Factor Bright

2005 ◽  
Vol 25 (6) ◽  
pp. 2073-2084 ◽  
Author(s):  
Jaya Rajaiya ◽  
Melissa Hatfield ◽  
Jamee C. Nixon ◽  
David J. Rawlings ◽  
Carol F. Webb
Keyword(s):  
B Cells ◽  
Dna Binding ◽  
Tyrosine Kinase ◽  
B Cell ◽  
Heavy Chain ◽  
Immunoglobulin Heavy Chain ◽  
Pleckstrin Homology Domain ◽  
Bruton’S Tyrosine Kinase ◽  
Immunoglobulin Gene ◽  
Bruton's Tyrosine Kinase

ABSTRACT Bright (B-cell regulator of immunoglobulin heavy chain transcription) binding to immunoglobulin heavy chain loci after B-cell activation is associated with increased heavy chain transcription. Our earlier reports demonstrated that Bright coimmunoprecipitates with Bruton's tyrosine kinase (Btk) and that these proteins associate in a DNA-binding complex in primary B cells. B cells from immunodeficient mice with a mutation in Btk failed to produce stable Bright DNA-binding complexes. In order to determine if Btk is important for Bright function, a transcription activation assay was established and analyzed using real-time PCR technology. Cells lacking both Bright and Btk were transfected with Bright and/or Btk along with an immunoglobulin heavy chain reporter construct. Immunoglobulin gene transcription was enhanced when Bright and Btk were coexpressed. In contrast, neither Bright nor Btk alone led to activation of heavy chain transcription. Furthermore, Bright function required both Btk kinase activity and sequences within the pleckstrin homology domain of Btk. Bright was not appreciably phosphorylated by Btk; however, a third tyrosine-phosphorylated protein coprecipitated with Bright. Thus, the ability of Bright to enhance immunoglobulin transcription critically requires functional Btk.

scholarly journals Complex regulation of the immunoglobulin mu heavy-chain gene enhancer: microB, a new determinant of enhancer function.

1990 ◽  
Vol 10 (6) ◽  
pp. 3145-3154 ◽  
Author(s):  
B Nelsen ◽  
T Kadesch ◽  
R Sen
Keyword(s):  
B Cell ◽  
Cell Lines ◽  
Heavy Chain ◽  
Chain Gene ◽  
Heavy Chain Gene ◽  
Enhancer Activity ◽  
Octamer Motif ◽  
Gene Enhancer ◽  
Heavy Chain Gene Enhancer ◽  
Immunoglobulin Mu

The B-lymphocyte-specific activity of the immunoglobulin mu heavy-chain gene enhancer has been attributed to the octamer motif (ATTTGCAT) present within the enhancer that binds a B-cell-specific factor designated NF-A2/OTF-2. However, significant residual enhancer activity even after deletion of this element has suggested the presence of a second critical functional determinant. We have used deletion and mutational analyses to define an element, microB (TTTGGGGAA), that is essential for B-cell-specific enhancer activity in S194 myeloma cells in the absence of the octamer. Transfection analysis in a panel of lymphoid cell lines suggests that the presence of either microB or octamer leads to considerable enhancer activity in cell lines representing later stages of B-cell differentiation, whereas both elements are needed for function in cell lines representing earlier stages. Furthermore, in contrast to the results in pre-B-cell lines, both microB and octamer elements function independently in certain T-cell lines in which the mu enhancer is active.

Complex regulation of the immunoglobulin mu heavy-chain gene enhancer: microB, a new determinant of enhancer function

1990 ◽  
Vol 10 (6) ◽  
pp. 3145-3154
Author(s):  
B Nelsen ◽  
T Kadesch ◽  
R Sen
Keyword(s):  
B Cell ◽  
Cell Lines ◽  
Heavy Chain ◽  
Chain Gene ◽  
Heavy Chain Gene ◽  
Enhancer Activity ◽  
Octamer Motif ◽  
Gene Enhancer ◽  
Heavy Chain Gene Enhancer ◽  
Immunoglobulin Mu

The B-lymphocyte-specific activity of the immunoglobulin mu heavy-chain gene enhancer has been attributed to the octamer motif (ATTTGCAT) present within the enhancer that binds a B-cell-specific factor designated NF-A2/OTF-2. However, significant residual enhancer activity even after deletion of this element has suggested the presence of a second critical functional determinant. We have used deletion and mutational analyses to define an element, microB (TTTGGGGAA), that is essential for B-cell-specific enhancer activity in S194 myeloma cells in the absence of the octamer. Transfection analysis in a panel of lymphoid cell lines suggests that the presence of either microB or octamer leads to considerable enhancer activity in cell lines representing later stages of B-cell differentiation, whereas both elements are needed for function in cell lines representing earlier stages. Furthermore, in contrast to the results in pre-B-cell lines, both microB and octamer elements function independently in certain T-cell lines in which the mu enhancer is active.

The normal IGHV1-69–derived B-cell repertoire contains stereotypic patterns characteristic of unmutated CLL

Blood ◽  
2010 ◽  
Vol 115 (1) ◽  
pp. 71-77 ◽  
Author(s):  
Francesco Forconi ◽  
Kathleen N. Potter ◽  
Isla Wheatley ◽  
Nikos Darzentas ◽  
Elisa Sozzi ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Heavy Chain ◽  
Immunoglobulin Heavy Chain ◽  
Immunoglobulin M ◽  
Lymphocytic Leukemia ◽  
Immunoglobulin Gene ◽  
Cell Of Origin ◽  
Cell Repertoire ◽  
B Cell Repertoire

Abstract The cell of origin of chronic lymphocytic leukemia (CLL) has long been sought, and immunoglobulin gene analysis provides new clues. In the unmutated subset (U-CLL), there is increased usage of the 51p1-related alleles of the immunoglobulin heavy chain variable 1-69 gene, often combined with selected genes and with immunoglobulin heavy chain diversity IGHJ6. Stereotypic characteristics of the HCDR3 result and suggest antigen selection of the leukemic clones. We have now analyzed 51p1/IGHJ6 combinations in normal blood B cells from 3 healthy persons for parallel sequence patterns. A high proportion (33.3% of sequences) revealed stereotypic patterns, with several (15.0%) being similar to those described in U-CLL. Previously unreported CLL-associated stereotypes were detected in 4.8%. Stereotypes (13.6%) not detected in CLL also were found. The HCDR2-IGHJ6 sequences were essentially unmutated. Junctional amino acids in normal B cells were heterogeneous, as in cases of stereotyped CLL. Phenotypically, normal B cells expressing 51p1-derived immunoglobulin M were naive. This snapshot of the naive B-cell repertoire reveals subsets of B cells closely related to those characteristic of CLL. Conserved patterns in the 51p1-encoded immunoglobulin M of normal B cells suggest a restricted sequence repertoire shaped by evolution to recognize common pathogens. Proliferative pressure on these cells is the likely route to U-CLL.

scholarly journals Pi, a pre-B-cell-specific enhancer element in the immunoglobulin heavy-chain enhancer.

1993 ◽  
Vol 13 (10) ◽  
pp. 5957-5969 ◽  
Author(s):  
T A Libermann ◽  
D Baltimore
Keyword(s):  
B Cell ◽  
Heavy Chain ◽  
Mutational Analysis ◽  
Protein S ◽  
Immunoglobulin Heavy Chain ◽  
Chain Gene ◽  
Cell Stage ◽  
Enhancer Activity ◽  
Enhancer Element ◽  
Light Chain Gene

We have identified a new immunoglobulin heavy-chain enhancer element, designated pi, between the microE2 and microE3 elements. The pi enhancer element is transcriptionally active primarily during early stages of B-cell development but becomes virtually inactive during B-cell maturation at about the stage of immunoglobulin kappa light-chain gene rearrangement. Mutational analysis suggests that the pi element is crucial for immunoglobulin heavy-chain enhancer activity at the pre-B-cell stage but is almost irrelevant for enhancer activity at the mature B-cell or plasma-cell stage. The activity of the pi enhancer element correlates with the presence of an apparently pre-B-cell-specific protein-DNA complex. The similarity of the pi site to recognition sequences for members of the ets gene family suggests that the protein(s) interacting with the pi site most likely are ets-related transcription factors.

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