OBF1, also known as Bob.1 or OCA-B, is a B lymphocyte-specific transcription factor which coactivates Oct1 and Oct2 on B cell specific promoters. So far, the function of OBF1 has been mainly identified in late stage B cell populations. The central defect of OBF1 deficient mice is a severely reduced immune response to T cell-dependent antigens and a lack of germinal center formation in the spleen. Relatively little is known about a potential function of OBF1 in developing B cells. Here we have generated transgenic mice overexpressing OBF1 in B cells under the control of the immunoglobulin heavy chain promoter and enhancer. Surprisingly, these mice have greatly reduced numbers of follicular B cells in the periphery and have a compromised immune response. Furthermore, B cell differentiation is impaired at an early stage in the bone marrow. A first block is observed during B cell commitment and a second differentiation block is seen at the large preB2 cell stage. The cells that succeed to escape the block and to differentiate into mature B cells have post-translationally downregulated the expression of transgene, indicating that expression of OBF1 beyond the normal level early in B cell development is deleterious. Indeed ID3, which is a negative regulator of B cell differentiation, is upregulated in the EPLM and preB cells of the transgenic mice. Furthermore ID3 promoter contains an octamer site suggesting that it is a potential OBF-1 direct target gene. These results provide evidence that OBF1 expression has to be tightly regulated in early B cells to allow efficient B lymphocyte differentiation.
Enforced expression of the transcriptional coactivator OBF1 impairs B cell differentiation at the earliest stage of development.
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View SamplesThe chromatin regulator Aiolos and the transcriptional coactivator OBF-1 have been implicated in regulating aspects of B cell maturation and activation. Mice lacking either of these factors have a largely normal early B cell development. However, when both factors are eliminated simultaneously a block is uncovered at the transition between pre-B and immature B cells, indicating that these proteins exert a critical function in developing B lymphocytes. In mice deficient for Aiolos and OBF-1, the numbers of immature B cells are reduced, small pre-BII cells are increased and a significant impairment in immunoglobulin light chain DNA rearrangement is observed. We identified genes whose expression is deregulated in the pre-B cell compartment of these mice. In particular, we found that components of the pre-BCR, such as the surrogate light chain genes l5l5 and VpreB, fail to be efficiently silenced in double-mutant mice. Strikingly, developmentally regulated nuclear repositioning of the l5l5 gene is impaired in pre-B cells lacking OBF-1 and Aiolos. These studies uncover a novel role for OBF-1 and Aiolos in controlling the transcription and nuclear organization of genes involved in pre-BCR function.
Silencing and nuclear repositioning of the lambda5 gene locus at the pre-B cell stage requires Aiolos and OBF-1.
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View SamplesThis SuperSeries is composed of the SubSeries listed below.
TTCA: an R package for the identification of differentially expressed genes in time course microarray data.
Cell line, Treatment
View SamplesThe analysis of microarray time series promises a deeper insight into the dynamics of the cellular response following stimulation. A common observation in this type of data is that some genes respond with quick, transient dynamics, while other genes change their expression slowly over time. The existing methods for the detection of significant expression dynamics often fail when the expression dynamics show a large heterogeneity, and often cannot cope with irregular and sparse measurements.
TTCA: an R package for the identification of differentially expressed genes in time course microarray data.
Cell line, Treatment
View SamplesThe analysis of microarray time series promises a deeper insight into the dynamics of the cellular response following stimulation. A common observation in this type of data is that some genes respond with quick, transient dynamics, while other genes change their expression slowly over time. The existing methods for the detection of significant expression dynamics often fail when the expression dynamics show a large heterogeneity, and often cannot cope with irregular and sparse measurements.
TTCA: an R package for the identification of differentially expressed genes in time course microarray data.
Cell line, Treatment
View SamplesThe microarray analysis was designed to test the effects of HES5.3 siRNAs, Atoh7 siRNAs and nt siRNAs on gene expression in embryonic chick retina.
A positive feedback loop between ATOH7 and a Notch effector regulates cell-cycle progression and neurogenesis in the retina.
Age, Specimen part
View SamplesNeutrophils are known to be stimulated by different periodontal bacteria to produce reactive oxygen species and cytokines. It is inportant to investigate the gene changes made by bacteria of importance, of which, for periodontal disease, fusobaterium nucleatum is one. we used microarrays to investigate gene experssion changes in peripheral blood neutrophils werwhich e stimulated with or with out Fusobacterium Nucleatum (10953).
Fusobacterium nucleatum regulation of neutrophil transcription.
Specimen part
View SamplesTo understand how an inhibition of the mitochondrial ATP synthase affects transcriptional programming and to identify potential candidates of the signaling machinery involved in ATP synthase deficiency responses, we used oligomycin on seedling liquid cultures. Seedlings were harvested at time points 0, 1 and 4 h after the start of oligomycin and control (EtOH) treatments. Already 1 h after addition of oligomycin a total of 102 genes were more than threefold up-regulated and 14 genes were repressed, with most of them showing persistent changes. After 4 h, 580 additional genes were more than threefold up-regulated, and 152 genes were repressed by oligomycin. Several genes for alternative NAD(P)H dehydrogenases and alternative oxidases (AOX1a, AOX1d and NDA1) were up-regulated early, and additional homologs (NDA2, NDB2, NDB4 and AOX1b) followed 4 h after the start of treatment. Several genes for subunits of complex I, complex IV and the ATP synthase were induced whereas hardly any genes encoding enzymes of glycolysis and the TCA cycle changed. Additionally, four of five hallmark genes for oxidative stress were increased by oligomycin. These genes are At2g21640 (UPOX), At1g19020, At1g05340 and At1g57630 and code for proteins of unknown function. Among oxidative stress proteins with known functions, several H2O2-responsive Glutathione-S-transferases and BCS1 (CYTOCHROME BC1 SYNTHESIS) were strongly up-regulated already after 1 h. BCS1 is induced by salicylic acid and independent of other reactive oxygen signaling (ROS) pathways, such as H2O2. The results indicate that several different ROS and defense signaling pathways were induced simultaneously by oligomycin. This is further corroborated by induction of several transcription factors of the WRKY and NAC families, which have been previously implicated in coordinating cellular defense signaling.
Downregulation of the δ-subunit reduces mitochondrial ATP synthase levels, alters respiration, and restricts growth and gametophyte development in Arabidopsis.
Specimen part, Treatment
View SamplesWe transformed Populus trichocarpa and generated transgenics with knockdown or overexpression of monolignol genes and transcription factors Overall design: RNAseq of xylem tissue of transgenic and wildtype Populus trichocarpa. 378 samples.
Modeling cross-regulatory influences on monolignol transcripts and proteins under single and combinatorial gene knockdowns in Populus trichocarpa.
Specimen part, Subject
View SamplesMissense mutations in transcription factor GATA1 underlie several distinct forms of anemia and thrombocytopenia. Clinical severity depends on the site and type of substitution, and distinct substiutions of the same residue produce disparate phenotypes. To investigate the effect of GATA1 missense mutations on erythroid differentiation we expressed conditionally activated wild type or mutant versions of GATA1 in GATA1-null G1E cells.
Analysis of disease-causing GATA1 mutations in murine gene complementation systems.
Specimen part
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