Activation du système de facteurs de transcription Rel/NF-κB

Costello, R; Lécine, Patrick; Kahn-Perlès, Brigitte; Algarté, Michèle; Lipcey, Carol; Olive, D; Imbert, Jean

doi:10.4267/10608/2395

Cited by 11 publications

(20 citation statements)

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“…In contrast, stimulation by anti CD2 or anti CD28 mAb alone did not give rise to a measurable level of thymidine incorporation (Figure 1b), nor to an increase in cell number. Similarly, CD2+CD28 costimulation activated the secretion of IL-2 which peaked around 4 days, as well as the expression of IL2Ra chain of the receptor at the cell surface, which lasted for at least 3 weeks, with more than 80% of the cells scoring positive (data not shown, Costello et al, 1993). Medium alone, single anti CD2 or anti CD28 stimulations, were ine ective in inducing a detectable level of secreted IL-2, neither an increase of IL-2Ra chain at the cell surface (data not shown).…”

Section: Cyclin a Expression In Primary Human T Lymphocytesmentioning

confidence: 88%

Relief of cyclin A gene transcriptional inhibition during activation of human primary T lymphocytes via CD2 and CD28 adhesion molecules

et al. 1997

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Cyclin A transcription is cell cycle regulated and induced by cell proliferative signals. To understand the mechanisms underlined in this regulation in normal human cells, we have analysed in vivo protein-DNA interactions at the Cyclin A locus in primary T lymphocytes. Stimulation of puri®ed T lymphocytes by a combination of monoclonal antibodies directed at CD2 and CD28 adhesion molecules gives rise to a long lasting proliferation in the absence of accessory cells. Cyclin A was observed after 4 days of costimulation with anti CD2+CD28 whereas stimulation by anti CD2 or anti CD28 alone was not e ective. In vivo genomic DMS footprinting revealed upstream of the major transcription initiation sites, the presence of at least three protein binding sites, two of which were constitutively occupied. They bind in vitro respectively ATF-1 and NF-Y proteins. The third site was occupied in quiescent cells or in cells stimulated by anti CD2 or anti CD28 alone. The mitogenic combination of anti CD2+ anti CD28 released the footprint as cells were committed to proliferation. Consistent with theses results, nuclear extracts prepared from quiescent cells formed a speci®c complex with this element, whereas extracts prepared from cells treated with anti CD2+ anti CD28 failed to do so after cells entered a proliferative state.

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Section: Cyclin a Expression In Primary Human T Lymphocytesmentioning

confidence: 88%

Relief of cyclin A gene transcriptional inhibition during activation of human primary T lymphocytes via CD2 and CD28 adhesion molecules

et al. 1997

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“…A similar assay with Kit225 nuclear extracts revealed that, beside a previously characterized minor Elf-1 component (Lecine et al, 1996), the C1 complex was also mainly composed of GABPa/b (data not shown). Since IL-2 secretion by CD2+CD28-stimulated T lymphocytes peaked at day 4 ± 6 (Costello et al, 1993), we focused on the DNAbinding speci®city and composition of the inducible C2p in T cells 6 days after stimulation. Competition experiments with wild-type, GAS and/or EBS disrupted oligonucleotides evidenced that C2p was speci®c for the GASd motif (Figure 6b), as reported above for IL-2-induced C2/C3 complexes in the leukemic T cell model Kit225.…”

Section: Cooperative Transcriptional Activation By Stat5b Ets-1 and mentioning

confidence: 99%

“…The cells were arrested in a quiescent state by washing them twice in PBS, and culturing in RPMI 1650 10% FCS without IL-2 for 20 h (for transient transfection assays) and for 2 days (for EMSAs, a nity puri®cation of DNA-binding proteins GST-pull down and immunoprecipitations). T cell puri®cation from human peripheral blood and activation were performed as described (Costello et al, 1993).…”

Section: Cell Culturementioning

confidence: 99%

“…EMSA, affinity purification of DNA-binding protein, GST-pull down, immunoprecipitation and immunoblotting Nuclear extracts (Costello et al, 1993) and whole cell extracts (Lecine et al, 1996) of Kit225 and primary T cells were prepared as described. Kit225 cells were IL-2-starved for 2 days and stimulated by IL-2 during 1 h. Synthetic oligonucleotidic probes were labeled with g-32 P ATP.…”

Section: Cell Culturementioning

confidence: 99%

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IL-2 and long-term T cell activation induce physical and functional interaction between STAT5 and ETS transcription factors in human T cells

et al. 2000

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Activation of Stat5 by many cytokines implies that it cannot alone insure the speci®city of the regulation of its target genes. We have evidenced a physical and functional interaction between members of two unrelated transcription factor families, Ets-1, Ets-2 and Stat5, which could contribute to the proliferative response to interleukin 2. Competition with GAS-and EBS-speci®c oligonucleotides and immunoassays with a set of antiStat and anti-Ets families revealed that the IL-2-induced Stat5-Ets complex recognizes several GAS motifs identi®ed as target sites for activated Stat5 dimers. Coimmunoprecipitation experiments evidenced that a Stat5/Ets-1/2 complex is formed in vivo in absence of DNA. GST-pull down experiments demonstrated that the C-terminal domain of Ets-1 is su cient for this interaction in vitro. Cotransfection experiments in Kit225 T cells resulted in cooperative transcriptional activity between both transcription factors in response to a combination of IL-2, PMA and ionomycin. A Stat5-Ets protein complex was the major inducible DNAbinding complex bound to the human IL-2rE GASd/ EBSd motif in long-term proliferating normal human T cells activated by CD2 and CD28. These results suggest that the inducible Stat5-Ets protein interaction plays a role in the regulation of gene expression in response to IL-2 in human T lymphocytes.

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“…T Cell Purification, Activation, and Treatments-T cell purification from peripheral blood and activation were performed as previously described (42). Primary T cells were maintained in RPMI, 10% fetal calf serum (FCS).…”

Section: Methodsmentioning

confidence: 99%

Sp1 Transcriptional Activity Is Up-regulated by Phosphatase 2A in Dividing T Lymphocytes

Lacroix

Lipcey

Imbert

et al. 2002

Journal of Biological Chemistry

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We have followed Sp1 expression in primary human T lymphocytes induced, via CD2 plus CD28 costimulation, to sustained proliferation and subsequent return to quiescence. Binding of Sp1 to wheat germ agglutinin lectin was not modified following activation, indicating that the overall glycosylation of the protein was unchanged. Sp1 underwent, instead, a major dephosphorylation that correlated with cyclin A expression and, thus, with cell cycle progression. A similar change was observed in T cells that re-entered cell cycle following secondary interleukin-2 stimulation, as well as in serum-induced proliferating NIH/3T3 fibroblasts. Phosphatase 2A (PP2A) appears involved because 1) treatment of dividing cells with okadaic acid or cantharidin inhibited Sp1 dephosphorylation and 2) PP2A dephosphorylated Sp1 in vitro and strongly interacted with Sp1 in vivo. Sp1 dephosphorylation is likely to increase its transcriptional activity because PP2A overexpression potentiated Sp1 site-driven chloramphenicol acetyltransferase expression in dividing Kit225 T cells and okadaic acid reversed this effect. This increase might be mediated by a stronger affinity of dephosphorylated Sp1 for DNA, as illustrated by the reduced DNA occupancy by hyperphosphorylated Sp factors from cantharidin-or nocodazole-treated cells. Finally, Sp1 dephosphorylation appears to occur throughout cell cycle except for mitosis, a likely common feature to all cycling cells.Sp1 is the founding member of a multigene family of transcription factors including Sp1, Sp2, Sp3, Sp4 (see Refs. 1-3 for reviews), and Sp5 proteins (4, 5). Both Sp1 and Sp3 are abundant and ubiquitous, whereas Sp4 is mainly expressed in neuronal tissues and Sp5 exhibits a dynamic and highly restricted expression pattern during embryogenesis. This protein family shares three highly conserved zinc finger DNA binding motifs that recognize GC or GT/CACC boxes present in many promoters. Sp1 was first viewed as a constitutive transcriptional activator regulating basal expression of many cellular and viral genes. However, it is now established that Sp1 activity is modulated in response to numerous signals and that this factor plays a critical role in cell growth and differentiation. Sp1 mediates the induction of dihydrofolate reductase (6) and thymidine kinase (7) genes associated with DNA synthesis and is therefore intricately linked to growth/cell cycle progression. In line with this, the ectopic expression of truncated Sp1 prolongs the S phase and reduces the growth rate (8). Conversely, Sp1 mediates cell division arrest by up-regulating the expression of genes coding for negative regulators of the cell cycle such as p2lWaf1/Cip1 , in p53-dependent growth control (9) or p53-independent pathway of terminal differentiation (10 -12).Sp1's manifold roles can be reconciled if one integrates the multiple time-ordered regulations to which this factor is itself submitted. First, Sp1 is a direct target of numerous cell cycle regulators, which activate or repress its activity. For instance, cyclin A (13...

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Activation du système de facteurs de transcription Rel/NF-κB

Cited by 11 publications

References 0 publications

Relief of cyclin A gene transcriptional inhibition during activation of human primary T lymphocytes via CD2 and CD28 adhesion molecules

Relief of cyclin A gene transcriptional inhibition during activation of human primary T lymphocytes via CD2 and CD28 adhesion molecules

IL-2 and long-term T cell activation induce physical and functional interaction between STAT5 and ETS transcription factors in human T cells

Sp1 Transcriptional Activity Is Up-regulated by Phosphatase 2A in Dividing T Lymphocytes

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