scholarly journals Targeting the GA Binding Protein β1L Isoform Does Not Perturb Lymphocyte Development and Function

2008 ◽  
Vol 28 (13) ◽  
pp. 4300-4309 ◽  
Author(s):  
Hai-Hui Xue ◽  
Xuefang Jing ◽  
Julie Bollenbacher-Reilley ◽  
Dong-Mei Zhao ◽  
Jodie S. Haring ◽  
...  
Keyword(s):  
B Cells ◽  
Target Genes ◽  
Splice Variants ◽  
Binding Protein ◽  
Critical Role ◽  
Dominant Negative ◽  
T And B Cells ◽  
Carboxy Terminal ◽  
And Function ◽  
Ga Binding Protein

ABSTRACT GA binding protein (GABP) is a ubiquitously expressed Ets family transcription factor that consists of two subunits, GABPα and GABPβ. GABPα binds to DNA, and GABPβ heterodimerizes with GABPα and possesses the ability to transactivate target genes. Our previous studies using GABPα-deficient mice revealed that GABPα is required for the development of both T and B cells. Two splice variants of GABPβ are generated from the Gabpb1 locus and differ in their carboxy-terminal lengths and sequences. The longer isoform (GABPβ1L) can homodimerize and thus form α2β2 tetramers depending on the gene context, whereas the shorter isoform (GABPβ1S) cannot. In this study, we generated mice that are deficient in GABPβ1L but that retain the expression of GABPβ1S. Surprisingly, GABPβ1L−/− mice had normal T- and B-cell development, and mature T and B cells showed normal responses to various stimuli. In contrast, targeting both GABPβ1L and GABPβ1S resulted in early embryonic lethality. Because of its incapability of forming homodimers, GABPβ1S has been suspected to have a dominant negative role in regulating GABP target genes. Our findings argue against such a possibility and rather suggest that GABPβ1S has a critical role in maintaining the transcriptional activity of the GABPα/β complex.

scholarly journals NF-κB RelA-deficient Lymphocytes: Normal Development of  T Cells and B Cells, Impaired Production of IgA and IgG1 and Reduced Proliferative Responses

1997 ◽  
Vol 185 (5) ◽  
pp. 953-962 ◽  
Author(s):  
Takahiro S. Doi ◽  
Toshitada Takahashi ◽  
Osamu Taguchi ◽  
Takachika Azuma ◽  
Yuichi Obata
Keyword(s):  
T Cells ◽  
B Cells ◽  
Fetal Liver ◽  
Critical Role ◽  
Calcium Ionophore ◽  
Scid Mice ◽  
T And B Cells ◽  
Liver Transplants ◽  
Liver Degeneration ◽  
And Function

To investigate the function of NF-κB RelA (p65), we generated mice deficient in this NF-κB family member by homologous recombination. Mice lacking RelA showed liver degeneration and died around embryonic day 14.5. To elucidate the role of RelA in lymphocyte development and function, we transplanted fetal liver cells of 13.5-day embryos from heterozygote matings into irradiated SCID mice. Within 4 weeks, both T and B cells had developed in the SCID mice receiving relA−/− fetal liver transplants, similar to the relA+/+ and +/− cases. T cells were found to mature to Thy-1+/TCRαβ+/CD3+/CD4+ or CD8+, while B cells had the ability to differentiate to IgM+/B220+ and to secrete immunoglobulins. However, the secretion of IgG1 and IgA was reduced in RelA-deficient B cells. Furthermore, both T and B cells lacking RelA showed marked reduction in proliferative responses to stimulation with Con A, anti-CD3, anti-CD3+anti-CD28, LPS, anti-IgM, and PMA+calcium ionophore. The results indicate that RelA plays a critical role in production of specific Ig isotypes and also in signal transduction pathways for lymphocyte proliferation.

The small GTPase Ral mediates SDF-1–induced migration of B cells and multiple myeloma cells

Blood ◽  
2008 ◽  
Vol 111 (7) ◽  
pp. 3364-3372 ◽  
Author(s):  
David J. J. de Gorter ◽  
Rogier M. Reijmers ◽  
Esther A. Beuling ◽  
Hildegonda P. H. Naber ◽  
Annemieke Kuil ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
B Cells ◽  
B Cell ◽  
Critical Role ◽  
Small Gtpase ◽  
Dominant Negative ◽  
Plasma Cell Neoplasm ◽  
Stromal Cell Derived Factor ◽  
B Cell Homeostasis ◽  
And Function

Abstract Chemokine-controlled migration plays a critical role in B-cell development, differentiation, and function, as well as in the pathogenesis of B-cell malignancies, including the plasma cell neoplasm multiple myeloma (MM). Here, we demonstrate that stimulation of B cells and MM cells with the chemokine stromal cell–derived factor-1 (SDF-1) induces strong migration and activation of the Ras-like GTPase Ral. Inhibition of Ral, by expression of the dominant negative RalN28 mutant or of RalBPΔGAP, a Ral effector mutant that sequesters active Ral, results in impaired SDF-1–induced migration of B cells and MM cells. Of the 2 Ral isoforms, RalA and RalB, RalB was found to mediate SDF-1–induced migration. We have recently shown that Btk, PLCγ2, and Lyn/Syk mediate SDF-1–controlled B-cell migration; however, SDF-1–induced Ral activation is not affected in B cells deficient in these proteins. In addition, treatment with pharmacological inhibitors against PI3K and PLC or expression of dominant-negative Ras did not impair SDF-1–induced Ral activation. Taken together, these results reveal a novel function for Ral, that is, regulation of SDF-1–induced migration of B cells and MM cells, thereby providing new insights into the control of B-cell homeostasis, trafficking, and function, as well as into the pathogenesis of MM.

Molecular and Functional Characterization of One Odorant-Binding Protein Gene OBP3 in Bemisia tabaci (Hemiptera: Aleyrodidae)

2019 ◽  
Author(s):  
Ran Wang ◽  
Yuan Hu ◽  
Peiling Wei ◽  
Cheng Qu ◽  
Chen Luo
Keyword(s):  
Host Plant ◽  
Bemisia Tabaci ◽  
Binding Protein ◽  
Insect Pest ◽  
Critical Role ◽  
Functional Characterization ◽  
Odorant Binding Protein ◽  
Binding Characteristics ◽  
And Function ◽  
Odorant Binding

Abstract Odorant binding proteins (OBPs) of insects play a critical role in chemical perceptions and choice of insect host plant. Bemisia tabaci is a notorious insect pest which can damage more than 600 plant species. In order to explore functions of OBPs in B. tabaci, here we investigated binding characteristics and function of odorant-binding protein 3 in B. tabaci (BtabOBP3). The results indicated that BtabOBP3 shows highly similar sequence with OBPs of other insects, including the typical signature motif of six cysteines. The recombinant BtabOBP3 protein was obtained, and the evaluation of binding affinities to tested volatiles of host plant was conducted, then the results indicated that β-ionone had significantly higher binding to BtabOBP3 among other tested plant volatiles. Furthermore, silencing of BtabOBP3 significantly altered choice behavior of B. tabaci to β-ionone. In conclusion, it has been demonstrated that BtabOBP3 exerts function as one carrier of β-ionone and the results could be contributed to reveal the mechanisms of choosing host plant in B. tabaci.

scholarly journals Regulation of the germinal center gene program by interferon (IFN) regulatory factor 8/IFN consensus sequence-binding protein

2005 ◽  
Vol 203 (1) ◽  
pp. 63-72 ◽  
Author(s):  
Chang Hoon Lee ◽  
Mark Melchers ◽  
Hongsheng Wang ◽  
Ted A. Torrey ◽  
Rebecca Slota ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Transcriptional Activation ◽  
Germinal Center ◽  
Target Genes ◽  
Fluorescent Protein ◽  
Binding Protein ◽  
Consensus Sequence ◽  
B Cell Lymphoma ◽  
Regulatory Factor

Interferon (IFN) consensus sequence-binding protein/IFN regulatory factor 8 (IRF8) is a transcription factor that regulates the differentiation and function of macrophages, granulocytes, and dendritic cells through activation or repression of target genes. Although IRF8 is also expressed in lymphocytes, its roles in B cell and T cell maturation or function are ill defined, and few transcriptional targets are known. Gene expression profiling of human tonsillar B cells and mouse B cell lymphomas showed that IRF8 transcripts were expressed at highest levels in centroblasts, either from secondary lymphoid tissue or transformed cells. In addition, staining for IRF8 was most intense in tonsillar germinal center (GC) dark-zone centroblasts. To discover B cell genes regulated by IRF8, we transfected purified primary tonsillar B cells with enhanced green fluorescent protein–tagged IRF8, generated small interfering RNA knockdowns of IRF8 expression in a mouse B cell lymphoma cell line, and examined the effects of a null mutation of IRF8 on B cells. Each approach identified activation-induced cytidine deaminase (AICDA) and BCL6 as targets of transcriptional activation. Chromatin immunoprecipitation studies demonstrated in vivo occupancy of 5′ sequences of both genes by IRF8 protein. These results suggest previously unappreciated roles for IRF8 in the transcriptional regulation of B cell GC reactions that include direct regulation of AICDA and BCL6.

scholarly journals Heterozygous Orthodenticle Homeobox 2 Mutations Are Associated with Variable Pituitary Phenotype

2010 ◽  
Vol 31 (1) ◽  
pp. 133-133
Author(s):  
Sumito Dateki ◽  
Kitaro Kosaka ◽  
Kosei Hasegawa ◽  
Hiroyuki Tanaka ◽  
Noriyuki Azuma ◽  
...  
Keyword(s):  
Target Genes ◽  
Japanese Patients ◽  
Dominant Negative ◽  
Pituitary Function ◽  
Hormone Deficiency ◽  
Dominant Negative Effect ◽  
Pituitary Hormone ◽  
Positive Role ◽  
Negative Effect ◽  
And Function

ABSTRACT Context Although recent studies have suggested a positive role of OTX2 in pituitary as well as ocular development and function, detailed pituitary phenotypes in OTX2 mutations and OTX2 target genes for pituitary function other than HESX1 and POU1F1 remain to be determined. Objective We aimed to examine such unresolved issues. Subjects We studied 94 Japanese patients with various ocular or pituitary abnormalities. Results We identified heterozygous p.K74fsX103 in case 1, p.A72fsX86 in case 2, p.G188X in two unrelated cases (3 and 4), and a 2,860,561-bp microdeletion involving OTX2 in case 5. Clinical studies revealed isolated GH deficiency in cases 1 and 5; combined pituitary hormone deficiency in case 3; abnormal pituitary structures in cases 1, 3, and 5; and apparently normal pituitary function in cases 2 and 4, together with ocular anomalies in cases 1-5. The wild-type Orthodenticle homeobox 2 (OTX2) protein transactivated the GNRH1 promoter as well as the HESX1, POU1F1, and IRBP (interstitial retinoid-binding protein) promoters, whereas the p.K74fsX103-OTX2 and p.A72fsX86-OTX2 proteins had no transactivation functions and the p.G188X-OTX2 protein had reduced (∼50%) transactivation functions for the four promoters, with no dominant-negative effect. cDNA screening identified positive OTX2 expression in the hypothalamus. Conclusions The results imply that OTX2 mutations are associated with variable pituitary phenotype, with no genotype-phenotype correlations, and that OTX2 can transactivate GNRH1 as well as HESX1 and POU1F1.

Signal transducer and activator of transcription 5a (STAT5a) is required for eosinophil differentiation of human cord blood–derived CD34+ cells

Blood ◽  
2003 ◽  
Vol 101 (1) ◽  
pp. 134-142 ◽  
Author(s):  
Miranda Buitenhuis ◽  
Belinda Baltus ◽  
Jan-Willem J. Lammers ◽  
Paul J. Coffer ◽  
Leo Koenderman
Keyword(s):  
Cord Blood ◽  
Target Genes ◽  
Ex Vivo ◽  
Critical Role ◽  
Ectopic Expression ◽  
Hematopoietic Cells ◽  
Myeloid Cell ◽  
Dominant Negative ◽  
Human Cord Blood ◽  
Cd34 Cells

Abstract Signal transducers and activators of transcription (STATs) have been reported to play a critical role in the differentiation of several myeloid cell lines, although the importance of STATs in the differentiation of primary human hematopoietic cells remains to be established. Terminal eosinophil differentiation is induced by interleukin-5 (IL-5), which has also been demonstrated to activate STAT5. We have investigated whether STAT5 plays a critical role during eosinophil differentiation using umbilical cord blood–derived CD34+ cells. In this ex vivo system, STAT5 expression and activation are high early during differentiation, and STAT5 protein expression is down-regulated during the final stages of eosinophil differentiation. Retroviral transductions were performed to ectopically express wild-type and dominant-negative STAT5a (STAT5aΔ750) in CD34+ cells. Transduction of cells with STAT5a resulted in enhanced proliferation compared with cells transduced with empty vector alone. Interestingly, ectopic expression of STAT5a also resulted in accelerated differentiation. In contrast, ectopic expression of STAT5aΔ750 resulted in a block in differentiation, whereas proliferation was also severely inhibited. Similar results were obtained with dominant-negative STAT5b. Forced expression of STAT5a enhanced expression of the STAT5 target genes Bcl-2 andp21WAF/Cip1, suggesting they may be important in STAT5a-mediated eosinophil differentiation. These results demonstrate that STAT5 plays a critical role in eosinophil differentiation of primary human hematopoietic cells.

Immunodeficiency Disorders

Hematology ◽  
2003 ◽  
Vol 2003 (1) ◽  
pp. 314-330 ◽  
Author(s):  
Max D. Cooper ◽  
Lewis L. Lanier ◽  
Mary Ellen Conley ◽  
Jennifer M. Puck
Keyword(s):  
B Cells ◽  
B Cell ◽  
Host Defense ◽  
Diagnosis And Treatment ◽  
T And B Cells ◽  
Phagocytic Cells ◽  
Effector Cells ◽  
Immunodeficiency Diseases ◽  
Cellular And Humoral Immunity ◽  
And Function

Abstract Hematological complications occur frequently in patients with both primary and secondary immunodeficiency disorders. Anemia, thrombocytopenia or leukopenias may bring these individuals to the attention of hematologists. Conversely, evidence suggesting a lymphoproliferative disorder may be the cause for referral. This session will provide an update on the diagnosis and treatment of immunodeficiency diseases ranging from isolated defects in antibody production to the severe combined immunodeficiencies (SCID). Immunodeficiency diseases have traditionally been defined as defects in the development and function of T and B cells, the primary effector cells of specific cellular and humoral immunity. However, it has become increasingly evident that innate immune mechanisms contribute greatly to host defense, either through acting alone or by enhancing specific T and B cell responses. In Section I, Dr. Lewis Lanier reviews the burgeoning information on the extensive families of activating and inhibitory immunoreceptors that are expressed on NK cells, dendritic cells, T and B cells, and phagocytic cells. He provides an overview on the biological functions of these receptors in host defense. In Section II, Dr. Mary Ellen Conley defines the spectrum of antibody deficiency disorders, the most frequently occurring types of primary immunodeficiencies. She covers the different defects in B-cell development and function that lead to antibody deficiencies, and includes diagnosis and therapy of these disorders. In Section III, Dr. Jennifer Puck discusses the diagnosis and treatment of the different types of SCID. She describes the genetic basis for SCID, and the benefits, pitfalls, and complications of gene therapy and bone marrow transplantation in SCID patients.

scholarly journals Cochaperone Mzb1 is a key effector of Blimp1 in plasma cell differentiation and β1-integrin function

2018 ◽  
Vol 115 (41) ◽  
pp. E9630-E9639 ◽  
Author(s):  
Virginia Andreani ◽  
Senthilkumar Ramamoorthy ◽  
Abhinav Pandey ◽  
Ekaterina Lupar ◽  
Stephen L. Nutt ◽  
...  
Keyword(s):  
Cell Differentiation ◽  
B Cells ◽  
Plasma Cell ◽  
Target Genes ◽  
Β1 Integrin ◽  
Plasma Cell Differentiation ◽  
And Migration ◽  
And Function ◽  
Antibody Secreting Cells

Plasma cell differentiation involves coordinated changes in gene expression and functional properties of B cells. Here, we study the role of Mzb1, a Grp94 cochaperone that is expressed in marginal zone (MZ) B cells and during the terminal differentiation of B cells to antibody-secreting cells. By analyzing Mzb1−/−Prdm1+/gfp mice, we find that Mzb1 is specifically required for the differentiation and function of antibody-secreting cells in a T cell-independent immune response. We find that Mzb1-deficiency mimics, in part, the phenotype of Blimp1 deficiency, including the impaired secretion of IgM and the deregulation of Blimp1 target genes. In addition, we find that Mzb1−/− plasmablasts show a reduced activation of β1-integrin, which contributes to the impaired plasmablast differentiation and migration of antibody-secreting cells to the bone marrow. Thus, Mzb1 function is required for multiple aspects of plasma cell differentiation.

scholarly journals Heterozygous Orthodenticle Homeobox 2 Mutations Are Associated with Variable Pituitary Phenotype

2010 ◽  
Vol 95 (2) ◽  
pp. 756-764 ◽  
Author(s):  
Sumito Dateki ◽  
Kitaro Kosaka ◽  
Kosei Hasegawa ◽  
Hiroyuki Tanaka ◽  
Noriyuki Azuma ◽  
...  
Keyword(s):  
Target Genes ◽  
Japanese Patients ◽  
Dominant Negative ◽  
Pituitary Function ◽  
Hormone Deficiency ◽  
Dominant Negative Effect ◽  
Pituitary Hormone ◽  
Positive Role ◽  
Negative Effect ◽  
And Function

Abstract Context: Although recent studies have suggested a positive role of OTX2 in pituitary as well as ocular development and function, detailed pituitary phenotypes in OTX2 mutations and OTX2 target genes for pituitary function other than HESX1 and POU1F1 remain to be determined. Objective: We aimed to examine such unresolved issues. Subjects: We studied 94 Japanese patients with various ocular or pituitary abnormalities. Results: We identified heterozygous p.K74fsX103 in case 1, p.A72fsX86 in case 2, p.G188X in two unrelated cases (3 and 4), and a 2,860,561-bp microdeletion involving OTX2 in case 5. Clinical studies revealed isolated GH deficiency in cases 1 and 5; combined pituitary hormone deficiency in case 3; abnormal pituitary structures in cases 1, 3, and 5; and apparently normal pituitary function in cases 2 and 4, together with ocular anomalies in cases 1–5. The wild-type Orthodenticle homeobox 2 (OTX2) protein transactivated the GNRH1 promoter as well as the HESX1, POU1F1, and IRBP (interstitial retinoid-binding protein) promoters, whereas the p.K74fsX103-OTX2 and p.A72fsX86-OTX2 proteins had no transactivation functions and the p.G188X-OTX2 protein had reduced (∼50%) transactivation functions for the four promoters, with no dominant-negative effect. cDNA screening identified positive OTX2 expression in the hypothalamus. Conclusions: The results imply that OTX2 mutations are associated with variable pituitary phenotype, with no genotype-phenotype correlations, and that OTX2 can transactivate GNRH1 as well as HESX1 and POU1F1.

Target Proteins of C/EBPa-p30 in AML: A Critical Role of Ubiquitin-Conjugating Enzyme (Ubc9) in Modulating C/EBPa-p42 Functions.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 2219-2219
Author(s):  
M. Geletu ◽  
M. Balkhi ◽  
A. Peer Zada ◽  
A. Trivedi ◽  
J. Pulikkan ◽  
...  
Keyword(s):  
Binding Protein ◽  
Critical Role ◽  
Protein A ◽  
Dominant Negative ◽  
Promoter Assay ◽  
Differentiation Capacity ◽  
Target Proteins ◽  
Calgranulin B ◽  
Ubiquitin Conjugating Enzyme ◽  
Conjugating Enzyme

Abstract The mutations in the transcription factor CCAAT/enhancer binding protein-a (C/EBPa) occur in 10% of patients with acute myeloid leukemia which often leads to the expression of an N-terminal truncated 30KDa isoform of C/EBPa. The mutated 30KDa isoform has been shown to be dominant negative over wild type isoform that affects most of its biological functions. In the present study, we applied a global proteomics approach to identify the target proteins of C/EBPap30. This analysis revealed that C/EBPap30 modulates the expression of 60 different proteins notably, ubiquitin-conjugating enzyme (Ubc9), Peptidylprolyl isomerase (pin1), hnRNP A2/B1, Cacyclin binding protein, calgranulin B, and Tubulin beta5. Further, we show that in AML patients with C/EBPap30 mutations Ubc9 was predominantly upregulated. We discovered that this ligase was responsible for the enhanced sumolyation of C/EBPap42 on a lysine residue (K161) which results in its reduced transactivation in a promoter assay. When lysine (K) residue at 161 of C/EBPa-p42 was mutated to argenine residue(R), transcriptional activity of C/EBPap42 was restored. This finding was further validated by silencing the expression of Ubc9 expression which completely abrogates the sumoylation at K161 residue and further restored the transactivation and differentiation capacity of C/EBPap42. Our results demonstrate that increasing expression of Ubc9 by C/EBPap30 enhances sumolyation of C/EBPap42 and thereby inhibits its transactivation and differentiation capacity.

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