scholarly journals A negative regulatory element in the bcl-2 5'-untranslated region inhibits expression from an upstream promoter.

1993 ◽  
Vol 13 (6) ◽  
pp. 3686-3697 ◽  
Author(s):  
R L Young ◽  
S J Korsmeyer
Keyword(s):  
B Cell ◽  
Cell Lines ◽  
Untranslated Region ◽  
Regulatory Element ◽  
Cell Development ◽  
Negative Control ◽  
B Cell Development ◽  
Negative Regulatory Element ◽  
Cis Acting ◽  
B Lineage

bcl-2 mRNA is present at high levels in pre-B-cell lines but is down-regulated in most mature B-cell lines. To investigate the mechanisms responsible for its developmental control, we studied the regulation of bcl-2 expression in human B-lineage cell lines. Using nuclear run-on assays, we found that bcl-2 transcription decreases in parallel with levels of steady-state mRNA during B-cell development. To define cis-acting elements that regulate bcl-2 transcription, we analyzed the expression of transiently transfected promoter-reporter constructs. We identified a novel negative regulatory element (NRE) in the bcl-2 5'-untranslated region that decreased expression from the bcl-2 P1 promoter or heterologous promoters in a position-dependent fashion. The NRE functions in either orientation but contains distinct orientation-dependent subfragments. Additional analyses demonstrated that multiple, functionally redundant sequence elements mediate NRE activity. Though the bcl-2 NRE is active in pre-B- and mature B-cell lines, chromatin structure of the endogenous NRE differs in these cells, suggesting that its activity or effect may vary during B-cell development. Our results indicate that negative control of transcription initiated at the P1 promoter is an important determinant of the differential expression of bcl-2.

scholarly journals A negative regulatory element in the bcl-2 5'-untranslated region inhibits expression from an upstream promoter

1993 ◽  
Vol 13 (6) ◽  
pp. 3686-3697
Author(s):  
R L Young ◽  
S J Korsmeyer
Keyword(s):  
B Cell ◽  
Cell Lines ◽  
Untranslated Region ◽  
Regulatory Element ◽  
Cell Development ◽  
Negative Control ◽  
B Cell Development ◽  
Negative Regulatory Element ◽  
Cis Acting ◽  
B Lineage

bcl-2 mRNA is present at high levels in pre-B-cell lines but is down-regulated in most mature B-cell lines. To investigate the mechanisms responsible for its developmental control, we studied the regulation of bcl-2 expression in human B-lineage cell lines. Using nuclear run-on assays, we found that bcl-2 transcription decreases in parallel with levels of steady-state mRNA during B-cell development. To define cis-acting elements that regulate bcl-2 transcription, we analyzed the expression of transiently transfected promoter-reporter constructs. We identified a novel negative regulatory element (NRE) in the bcl-2 5'-untranslated region that decreased expression from the bcl-2 P1 promoter or heterologous promoters in a position-dependent fashion. The NRE functions in either orientation but contains distinct orientation-dependent subfragments. Additional analyses demonstrated that multiple, functionally redundant sequence elements mediate NRE activity. Though the bcl-2 NRE is active in pre-B- and mature B-cell lines, chromatin structure of the endogenous NRE differs in these cells, suggesting that its activity or effect may vary during B-cell development. Our results indicate that negative control of transcription initiated at the P1 promoter is an important determinant of the differential expression of bcl-2.

Staging B-Cell Development and the Role of Ig Gene Rearrangement in B Lineage Progression

1998 ◽  
pp. 255-266
Author(s):  
Richard R. Hardy ◽  
Susan Shinton ◽  
Robert Wasserman ◽  
Yue-Sheng Li
Keyword(s):  
B Cell ◽  
Gene Rearrangement ◽  
Cell Development ◽  
B Cell Development ◽  
B Lineage

B Cell Lineage-Specific Deletion of Icsbp/IRF8 Reveals Roles for IRF8 in the Regulation of Marginal Zone and Follicular B Cell Development.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 1334-1334
Author(s):  
Hongsheng Wang ◽  
Jianxun Feng ◽  
Chang Hoon Lee ◽  
Herbert Morse
Keyword(s):  
B Cells ◽  
B Cell ◽  
Marginal Zone ◽  
Cell Development ◽  
B Cell Development ◽  
Conditional Knockout ◽  
Myelogenous Leukemia ◽  
Exon 2 ◽  
B Lineage ◽  
B Lineage Cells

Abstract Interferon regulatory factor 8 (IRF8), also known as interferon consensus sequence-binding protein (ICSBP), is a transcription factor that expresses in T cells, B cells and macrophages and plays a role in myeloid development. Targeted deletion of IRF8 in mice (IRF8−/−) induced progressive increase in the numbers of granulocytes in various lymphoid organs and development of a syndrome similar to human chronic myelogenous leukemia. In addition to defective development of macrophages and dendritic cells, B cell development was also impaired in IRF8−/− mice. This includes decreased numbers of early B cells, expanded marginal zone (MZ) B cells and diminished follicular (OF) B2 cells. Because abnormal myeloid cells could alter microenvironment required for normal B cell development, we have generated IRF8 conditional knockout mice to specifically investigate the function of IRF8 in B lineage cells. Mice were engineered to have exon 2, encoding the DNA binding domain of IRF8, flanked by loxP sites (designated IRF8f/+). These mice were then crossed with the CD19Cre strain in which the expression of Cre-recombinase is controlled by the endogenous CD19 locus. Homozygous mice (designated (IRF8f/f x Cre)F1) underwent germline excision of IRF8 in CD19+ B lineage cells. As a result, there was no detectable mRNA and protein of IRF8 in their splenic B cells. Flow cytometry analysis revealed expanded MZ B cells and reduced OF B2 cells in the spleen of (IRF8f/f x Cre)F1 mice. Interestingly, the expression level of CD23 on OF B cells was significantly decreased in (IRF8f/f x Cre)F1 mice, indicating that IRF8 is required for maintaining a normal OF phenotype. In the peritoneum of (IRF8f/f x Cre)F1 mice, while the numbers of B1a and B2 cells were slightly decreased, the number of B1b cells was slightly increased. Furthermore, BXH2 mice carrying a mutation (C915T) in the Icsbp1 gene exhibited similar expansion of MZ B cells and low expression of CD23 in OF B cells. Taken together, these analyses indicate that IRF8 is required for development of normal MZ and B2 cells.

scholarly journals The Earliest Step in B Lineage Differentiation from Common Lymphoid Progenitors Is Critically Dependent upon Interleukin 7

2002 ◽  
Vol 196 (5) ◽  
pp. 705-711 ◽  
Author(s):  
Juli P. Miller ◽  
David Izon ◽  
William DeMuth ◽  
Rachel Gerstein ◽  
Avinash Bhandoola ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Cell Development ◽  
B Cell Development ◽  
Gamma Chain ◽  
Lineage Differentiation ◽  
Lymphoid Progenitors ◽  
B Lineage

Little is known about the signals that promote early B lineage differentiation from common lymphoid progenitors (CLPs). Using a stromal-free culture system, we show that interleukin (IL)-7 is sufficient to promote the in vitro differentiation of CLPs into B220+ CD19+ B lineage progenitors. Consistent with current models of early B cell development, surface expression of B220 was initiated before CD19 and was accompanied by the loss of T lineage potential. To address whether IL-7 receptor (R) activity is essential for early B lineage development in vivo, we examined the frequencies of CLPs and downstream pre–pro- and pro-B cells in adult mice lacking either the α chain or the common gamma chain (γc) of the IL-7R. The data indicate that although γc−/− mice have normal frequencies of CLPs, both γc−/− and IL-7Rα−/− mice lack detectable numbers of all downstream early B lineage precursors, including pre–pro-B cells. These findings challenge previous notions regarding the point in B cell development affected by the loss of IL-7R signaling and suggest that IL-7 plays a key and requisite role during the earliest phases of B cell development.

RNA analysis of B cell lines arrested at defined stages of differentiation allows for an approximation of gene expression patterns during B cell development

2003 ◽  
Vol 74 (1) ◽  
pp. 102-110 ◽  
Author(s):  
Panagiotis Tsapogas ◽  
Thomas Breslin ◽  
Sven Bilke ◽  
Anna Lagergren ◽  
Robert Månsson ◽  
...  
Keyword(s):  
Gene Expression ◽  
B Cell ◽  
Cell Lines ◽  
Expression Patterns ◽  
Cell Development ◽  
B Cell Development ◽  
Gene Expression Patterns ◽  
Rna Analysis

scholarly journals E2A expression, nuclear localization, and in vivo formation of DNA- and non-DNA-binding species during B-cell development.

1993 ◽  
Vol 13 (12) ◽  
pp. 7321-7333 ◽  
Author(s):  
Y Jacobs ◽  
C Vierra ◽  
C Nelson
Keyword(s):  
B Cell ◽  
Electrophoretic Mobility ◽  
Cell Lines ◽  
Nuclear Localization ◽  
Cell Development ◽  
B Cell Development ◽  
Mobility Shift ◽  
Electrophoretic Mobility Shift Assays

A monoclonal antibody (Yae) was characterized and shown to specifically recognize E2A proteins in vivo, including the E2A-Pbx1 fusion gene products, p77E2A-Pbx1 and p85E2A-Pbx1. E2A proteins of a predominant molecular mass of 72 kDa, which comigrated with in vitro-produced rat E12 and and rat E47, were detected in human pro-B, pre-B, mature B, and plasma cell lines. The Yae antibody detected an E2A-containing microE2 enhancer element-binding complex (BCF-1) in pre-B- and mature B-cell lines in electrophoretic mobility shift assays which displayed a migration rate similar to that of in vitro-produced rat E12 and rat E47. A new E2A-containing microE2-binding species (P-E2A) was identified in plasma cells by using electrophoretic mobility shift assays. E2A proteins were detected in pro-B cells but were unable to bind the microE2 site. These observations suggest that the microE2 site is the target of stage-specific E2A regulatory complexes during B-cell development. Immunostaining analyses demonstrated the predominant nuclear localization of E2A proteins. Finally, we have identified an E2A form, designated I-E2A, which is unable to bind DNA. Our observations demonstrate novel in vivo mechanisms for the regulation of transcription by E2A proteins during B-cell development.

scholarly journals B1 and B2 B cells are characterized by distinct CpG modification states at DNMT3A-maintained enhancers

2020 ◽  
Author(s):  
Vinay S. Mahajan ◽  
Hamid Mattoo ◽  
Na Sun ◽  
Vinayak Viswanadham ◽  
Grace J. Yuen ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
B Lymphocytes ◽  
Cell Development ◽  
Methylation Pattern ◽  
B Cell Development ◽  
Developmental Expression ◽  
B Lineage ◽  
Tet Enzymes ◽  
Lineage Specific Genes

AbstractWe show that DNA methylation is a layered process in B lymphocytes. An underlying foundational methylome is stably established during B lineage commitment and overlaid with a DNMT3A-maintained dynamic methylome which is sculpted in distinct ways in B1 and B2 B cells during B cell development. An engineered loss of DNMT3A after commitment to the B lineage unmasks a foundational methylome that is shared in both B1 and B2 sub-lineages. The dynamic methylome is comprised of novel enhancers whose methylation state is maintained by DNMT3A but can be modulated in strikingly different ways in B1 and B2 B cells. During B1 B cell development, the dynamic methylome undergoes a prominent programmed demethylation event that is not observed during B2 B cell development. The methylation pattern of the dynamic methylome is determined by the coincident recruitment of DNMT3A and TET enzymes and it regulates the developmental expression of B1 and B2 lineage-specific genes.

Tissue-specific expression of the human CD19 gene in transgenic mice inhibits antigen-independent B-lymphocyte development

1994 ◽  
Vol 14 (6) ◽  
pp. 3884-3894
Author(s):  
L J Zhou ◽  
H M Smith ◽  
T J Waldschmidt ◽  
R Schwarting ◽  
J Daley ◽  
...  
Keyword(s):  
Cell Differentiation ◽  
Cell Surface ◽  
Transgenic Mice ◽  
B Cell ◽  
B Lymphocyte ◽  
Cell Development ◽  
B Cell Development ◽  
Specific Expression ◽  
B Lineage

CD19 is a B-cell-specific member of the immunoglobulin superfamily expressed from early pre-B-cell development until plasma cell differentiation. In vitro studies demonstrate that the CD19 signal transduction molecule can serve as a costimulatory molecule for activation through other B-lymphocyte cell surface molecules. However, much remains to be known regarding how CD19 functions in vivo and whether CD19 has different roles at particular stages of B-cell differentiation. Therefore, transgenic mice overexpressing the human CD19 (hCD19) gene were generated to determine whether this transgene would be expressed in a B-lineage-specific fashion and to dissect the in vivo role of CD19 in B-cell development and activation. Expression of the human transgene product was specifically restricted to all B-lineage cells and appeared early in development as occurs with hCD19. In addition, expression of hCD19 severely impaired the development of immature B cells in the bone marrow, with dramatically fewer B cells found in the spleen, peripheral circulation, and peritoneal cavity. The level of hCD19 expressed on the cell surface correlated directly with the severity of the defect in different transgenic lines. These results demonstrate that the hCD19 gene is expressed in a lineage-specific fashion in mice, indicating that the hCD19 gene may be useful for mediating B-lineage-specific expression of other transgene products. In addition, these results indicate an important role for the lineage-specific CD19 molecule during early B-cell development before antigen-dependent activation.

E2A expression, nuclear localization, and in vivo formation of DNA- and non-DNA-binding species during B-cell development

1993 ◽  
Vol 13 (12) ◽  
pp. 7321-7333
Author(s):  
Y Jacobs ◽  
C Vierra ◽  
C Nelson
Keyword(s):  
B Cell ◽  
Electrophoretic Mobility ◽  
Cell Lines ◽  
Nuclear Localization ◽  
Cell Development ◽  
B Cell Development ◽  
Mobility Shift ◽  
Electrophoretic Mobility Shift Assays

A monoclonal antibody (Yae) was characterized and shown to specifically recognize E2A proteins in vivo, including the E2A-Pbx1 fusion gene products, p77E2A-Pbx1 and p85E2A-Pbx1. E2A proteins of a predominant molecular mass of 72 kDa, which comigrated with in vitro-produced rat E12 and and rat E47, were detected in human pro-B, pre-B, mature B, and plasma cell lines. The Yae antibody detected an E2A-containing microE2 enhancer element-binding complex (BCF-1) in pre-B- and mature B-cell lines in electrophoretic mobility shift assays which displayed a migration rate similar to that of in vitro-produced rat E12 and rat E47. A new E2A-containing microE2-binding species (P-E2A) was identified in plasma cells by using electrophoretic mobility shift assays. E2A proteins were detected in pro-B cells but were unable to bind the microE2 site. These observations suggest that the microE2 site is the target of stage-specific E2A regulatory complexes during B-cell development. Immunostaining analyses demonstrated the predominant nuclear localization of E2A proteins. Finally, we have identified an E2A form, designated I-E2A, which is unable to bind DNA. Our observations demonstrate novel in vivo mechanisms for the regulation of transcription by E2A proteins during B-cell development.

B Cell Development in the Absence of PU.1.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 226-226 ◽  
Author(s):  
Min Ye ◽  
Olga Ermaermakova-Cirilli ◽  
Thomas Graf
Keyword(s):  
Bone Marrow ◽  
B Cells ◽  
B Cell ◽  
Target Genes ◽  
Fetal Liver ◽  
Cell Formation ◽  
Cell Development ◽  
B Cell Development ◽  
B Lineage

Abstract Mice deficient of the ETS-family transcription factor PU.1 lack B cells as well as macrophages. While most macrophage specific genes are known to be regulated by high levels of PU.1, the reason for the defect in B cell formation is not known. Here we analyzed a mouse strain in which a floxed version of the PU.1 gene, surrounding exon 4 and 5, which encode the DNA, binding and PEST domains (developed by C. Somoza and D. Tenen), was excised by Cre mediated recombination. As expected, this strain lacks both B cells and macrophages and die at birth. Surprisingly, however, we were able to establish lymphoid cell lines from fetal livers of these mice (day 14 to day 18), which proliferated on S17 stromal cells supplemented with IL-7 and stem cell factor. These cells expressed the B lineage cell surface markers CD19, CD43, BP-1 and CD24, but not B220. They also expressed B cell transcription factors, EBF, E47, Pax5, and their target genes, Rag1, IL7R, λ5 and v-preB, as detected by RT-PCR, exhibited DJ and VDJ immunoglobulin heavy chain rearrangements, and expressed IgM after IL-7 withdrawal. We then tested the effect of PU.1 deletion in B cells in adult animals by crossing the floxed PU.1 strain with a CD19 Cre mouse line. The spleen and peripheral blood (but not bone marrow) of these mice contained B cells that were CD19+ IgMlow, IgDhigh but B220 negative and instead expressed CD43. Thus PU.1 is not essential for immunoglobulin production and late B cell development. Although PU.1−/− fetal liver cells can give rise to cells, resembling Pre-B in vitro, the process of B cell formation was delayed by almost 12 days, compared with wt fetal liver, and the efficiency was reduced approximately 25-fold. In addition, PU.1 deficient B cells demonstrated an impaired ability to engraft into the bone marrow, when injected into irradiated SCID mice. We have found that PU.1 deficient B progenitors showed reduced or undetectable levels of the SDF1 receptor CXCR4, a receptor that has been implicated in B cell homing. Taken together, our observations suggest that PU.1 plays two different roles during B cell development: for early B cell formation and for proper migration and engraftment, which might be mediated through regulation of CXCR4 expression.

Sign in / Sign up

Export Citation Format

Share Document