Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:Q15744 (C/EBP epsilon)
 82 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Chicken NF-M transcription factor, in cooperation with either c-Myb or v-Myb, is active in the combinatorial activation of myeloid-cell-specific genes in heterologous cell types, such as embryonic fibroblasts. In humans, similar effects were observed with homologous members of the CCAAT/enhancer-binding protein (C/EBP) family of transcriptional regulators, especially the human homolog of chicken NF-M, C/EBP-beta (NF-IL6). However, the NF-IL6 gene is expressed in a variety of nonmyeloid cell types and is strongly inducible in response to inflammatory stimuli, making it an unlikely candidate to have an exclusive role as a combinatorial differentiation switch during myelopoiesis in human cells. By using a reverse transcription-PCR-based approach and a set of primers specific for the DNA-binding domains of highly homologous members of the C/EBP family of transcriptional regulators, we have cloned a novel human gene encoding a member of the C/EBP gene family, identified as the human homolog of CRP1, C/EBP-epsilon. A 1.2-kb cDNA encoding full-length human C/EBP-epsilon was cloned from a promyelocyte-late myeloblast-derived lambda gt11 library. Molecular analysis of the cDNA and genomic clones indicated the presence of two exons encoding a protein with an apparent molecular mass of 32 kDa and a pI of 9.5. Primer extension analysis of C/EBP-epsilon mRNA detected a single major transcription start site approximately 200 bp upstream of the start codon. The putative promoter area is similar to those of several other myeloid-cell-specific genes in that it contains no TATAAA box but has a number of purine-rich stretches with multiple sites for the factors of the Ets family of transcriptional regulators. Northern blot analyses indicated a highly restricted mRNA expression pattern, with the strongest expression occurring in promyelocyte and late-myeloblast-like cell lines. Western blot and immunoprecipitation studies using rabbit anti-C/EBP-epsilon antibodies raised against the N-terminal portion of C/EBP-epsilon (amino acids 1 to 115) showed that C/EBP-epsilon is a 32-kDa nuclear phosphoprotein. The human C/EBP-epsilon protein exhibited strong and specific binding to double-stranded DNA containing consensus C/EBP sites. Cotransfection of the C/EBP-epsilon sense and antisense expression constructs together with chloramphenicol acetyltransferase reporter vectors containing myeloid-cell-specific c-mim and human myeloperoxidase promoters suggested a role for C/EBP-epsilon transcription factor in the regulation of a subset of myeloid-cell-specific genes. Transient tranfection of a promyelocyte cell line (NB4) with a C/EBP-epsilon expression plasmid increased cell growth by sevenfold, while antisense C/EBP-epsilon caused a fivefold decrease in clonal growth of these cells.
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PMID:Cloning of the novel human myeloid-cell-specific C/EBP-epsilon transcription factor. 903 64

We and others have cloned a novel human gene CCAAT/enhancer-binding protein epsilon (C/EBP-epsilon) encoding a member of the C/EBP gene family. It is exclusively expressed in myeloid and T-lymphoid cells and appears to have an important role in inducing expression of several myeloid-specific genes. We used a polymerase chain reaction (PCR)-based technique to examine DNA from 93 hamster/human radiation hybrid clones in order chromosomally to map C/EBP-epsilon to 14q11.2 (between D14S264 and D14S275) which is telomeric to the T-cell receptor alpha and delta genes and centromeric to several other myeloid gene products including Cathepsin G (CTSG) and Chymase-1 (CMA1). To determine whether C/EBP-epsilon behaves as an altered tumor-suppressor gene, samples from patients with acute myelogenous leukemia (AML) and myelodysplastic syndrome (MDS) evolving to AML were studied for loss of heterozygosity (LOH) using microsatellite sequences that we identified within 0.2 kb of the amino-terminus of the human C/EBP-epsilon gene. Allelic loss of the C/EBP-epsilon gene was detected in four out of 20 (20%) evolving MDS cases and in none of the 17 AML and 17 T-cell leukemia cases. Mutational analysis of the gene was performed using PCR-SSCP on 37 AML and 40 MDS cases including those with LOH at the gene. No abnormalities were found suggesting that the altered gene in this region is not C/EBP-epsilon. Also, C/EBP-epsilon was examined by Southern blot analysis on DNA samples from 20 AML patients and 10 AML cell lines. No rearrangements or amplifications of the gene were detected. Taken together, we have mapped C/EBP-epsilon to 14q11.2, a region containing other myeloid and T-lymphoid specific genes. Furthermore, no structural alterations were detected in the C/EBP-epsilon gene.
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PMID:C/EBP-epsilon: chromosomal mapping and mutational analysis of the gene in leukemia and preleukemia. 939 98

Human CCAAT/enhancer-binding protein epsilon (C/EBPepsilon), a new member of the C/EBP family, significantly up-regulates both the mim-1 and human myeloperoxidase promoters, suggesting an important role for C/EBPepsilon in the transcriptional regulation of a subset of myeloid-specific genes. To elucidate the structure and function of C/EBPepsilon in transcriptional activation, amino acid residues 1-115, 147-249, or 1-249 of C/EBPepsilon were fused to the yeast GAL4 DNA binding domain. These expression vectors were cotransfected with a chloramphenicol acetyltransferase reporter gene and, in all cell lines tested, only the GAL-C/EBPepsilon-(1-115) fusion protein significantly activated expression from the chloramphenicol acetyltransferase reporter gene. Sixteen deletion mutants of C/EBPepsilon mapped the transactivation domain to amino acids 1-18 at the N terminus and revealed the presence of a transcription repression element between amino acid residues 116 and 162. Expression vectors containing the repression domain of C/EBPepsilon strongly inhibited gene transcription from TK, SV40, and adenoviral major late promoters bearing GAL4 binding sites. Fusion of this repression domain to the VP16 activation domain inhibited the transactivation function of VP16. Deletion of this repression domain increased gene transcription from a neutrophil elastase promoter-luciferase reporter. Taken together, these data suggest that C/EBPepsilon regulates transcription by utilizing both activation and repression functions.
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PMID:Identification of transcriptional activation and repression domains in human CCAAT/enhancer-binding protein epsilon. 961 80

CCAAT/enhancer-binding protein epsilon (C/EBPepsilon) is expressed almost exclusively in the myeloid lineage of the hematopoietic system and functions during terminal differentiation of neutrophils and macrophages, and in the regulation of cytokine gene expression in macrophages and T cells. We have undertaken a series of structure/function studies on the murine C/EBPepsilon polypeptide to investigate the mechanism by which C/EBPepsilon activates transcription. Studies with deletion mutants and fusion proteins consisting of C/EBPepsilon sequences joined to the Gal4 DNA-binding protein identified two transcriptional activation domains in C/EBPepsilon. Removal of sequences between the two activation domains or sequences between the second activation domain and the C-terminal DNA binding domain significantly increased the activity of C/EBPepsilon, suggesting the presence of two separate regulatory domains (designated RD-1epsilon and RD-2epsilon). RD-1epsilon behaved as a classic active repressor domain being capable of inhibiting adjacent activation domains irrespective of their origin and when linked to a heterologous DNA binding domain. Mutagenesis studies revealed a short motif in RD-1epsilon that appears to be a target site for protein-protein interactions and is conserved in repressor domains from C/EBPbeta, Sp3, c-Fos, and FosB. The juxtaposition of activation and repressor domains may permit C/EBPepsilon to function as a transcriptional activator or repressor at different stages of myeloid differentiation or as an inducible transcriptional activator of cytokine genes.
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PMID:A short conserved motif is required for repressor domain function in the myeloid-specific transcription factor CCAAT/enhancer-binding protein epsilon. 993 9

The genes encoding Hoxa9 and Meis1 are transcriptionally coactivated in a subset of acute myeloid leukemia (AML) in mice. In marrow reconstitution experiments, coexpression of both genes produces rapid AML, while neither gene alone generates overt leukemia. Although Hoxa9 and Meis1 can bind DNA as heterodimers, both can also heterodimerize with Pbx proteins. Thus, while their coactivation may result from the necessity to bind promoters as heterodimers, it may also result from the necessity of altering independent biochemical pathways that cooperate to generate AML, either as monomers or as heterodimers with Pbx proteins. Here we demonstrate that constitutive expression of Hoxa9 in primary murine marrow immortalizes a late myelomonocytic progenitor, preventing it from executing terminal differentiation to granulocytes or monocytes in the presence of granulocyte-macrophage colony-stimulating factor (GM-CSF) or interleukin-3. This immortalized phenotype is achieved in the absence of endogenous or exogenous Meis gene expression. The Hoxa9-immortalized progenitor exhibited a promyelocytic transcriptional profile, expressing PU.1, AML1, c-Myb, C/EBP alpha, and C/EBP epsilon as well as their target genes, the receptors for GM-CSF, G-CSF, and M-CSF and the primary granule proteins myeloperoxidase and neutrophil elastase. G-CSF obviated the differentiation block of Hoxa9, inducing neutrophilic differentiation with accompanying expression of neutrophil gelatinase B and upregulation of gp91phox. M-CSF also obviated the differentiation block, inducing monocytic differentiation with accompanying expression of the macrophage acetyl-low-density lipoprotein scavenger receptor and F4/80 antigen. Versions of Hoxa9 lacking the ANWL Pbx interaction motif (PIM) also immortalized a promyelocytic progenitor with intrinsic biphenotypic differentiation potential. Therefore, Hoxa9 evokes a cytokine-selective block in differentiation by a mechanism that does not require Meis gene expression or interaction with Pbx through the PIM.
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PMID:Hoxa9 immortalizes a granulocyte-macrophage colony-stimulating factor-dependent promyelocyte capable of biphenotypic differentiation to neutrophils or macrophages, independent of enforced meis expression. 1075 11

In vitro models of granulopoiesis involving the inducible expression of either CCAAT enhancer binding protein alpha (C/EBP alpha) or C/EBP epsilon in myeloid cells have been shown to lead to the induction of a granulocytic maturation program accompanied by the expression of myeloid-specific genes. Since members of the C/EBP family of transcription factors recognize and bind to similar DNA-binding motifs, it has been difficult to elucidate the specific role of each of the C/EBP family members in eliciting myeloid gene expression. In order to address this issue, we focused on the expression of the lactoferrin (LF) gene. LF expression is transcriptionally regulated in a C/EBP-dependent manner in myeloid cells. Using chromatin immunoprecipitation (ChIP) analysis we demonstrate that C/EBP alpha binds to the LF promoter in nonexpressing cells. Upon induction of maturation, C/EBP epsilon binds to the LF promoter, which correlates with LF expression. Lack of LF expression in the acute promyelocytic leukemia cell line NB4, which harbors the t(15;17) translocation, cannot be correlated with aberrant binding at the C/EBP site in the LF promoter. It is, however, associated with the persistent binding of the silencer CCAAT displacement protein (CDP/cut) to the LF promoter in these cells. We conclude that C/EBP alpha, C/EBP epsilon, and CDP/cut all play definitive roles in regulating late gene expression during normal myeloid development.
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PMID:Chromatin immunoprecipitation (ChIP) studies indicate a role for CCAAT enhancer binding proteins alpha and epsilon (C/EBP alpha and C/EBP epsilon ) and CDP/cut in myeloid maturation-induced lactoferrin gene expression. 1252

Ceramide, formed by sphingomyelinase, is involved in the expression of cyclooxygenase-2 (COX-2). This study examines the effect of C2-ceramide (C2), a cell-permeable ceramide analog, on the lipopolysaccharide (LPS)-inducible COX-2 expression and signaling pathways. C2 did not induce COX-2 but potentiated LPS-inducible COX-2 expression in Raw264.7 cells, whereas dihydro-C2 was inactive. Treatment of cells with C2 notably increased LPS-inducible CCAAT/enhancer binding protein (C/EBP) DNA binding. Antibody supershift experiments revealed that LPS-induced C/EBP DNA binding activity depended on C/EBP beta and C/EBP delta but not C/EBP alpha, C/EBP epsilon or CBP/p300. C/EBP beta contributed to C2-enhanced DNA binding activity. 4-(4-Fluorophenyl)-2-(4-methylsulfinylphenyl)-5-(4-pyridyl) 1H-imidazole (SB203580), a p38 kinase inhibitor, completely inhibited LPS-inducible and C2-potentiated LPS-inducible COX-2 expression. Enhancement of LPS-inducible COX-2 expression and C/EBP DNA binding by C2 was abrogated in dominant-negative mutant of JNK1 [JNK1(-)] cells. 2'-Amino-3'-methoxyflavone (PD98059) or stable transfection with dominant-negative mutant of MKK1 decreased COX-2 induction by LPS but failed to inhibit C2-enhanced LPS induction of COX-2. Transfection with dominant-negative mutant of C/EBP inhibited the ability of C2 to potentiate the induction of COX-2 by LPS. In LPS-treated cells, C2 enhanced both the nuclear translocation and the expression of LPS-inducible C/EBP beta with an increase in AP-1 DNA binding activity. These enhancements were abolished by JNK1(-) transfection. AP-1 decoy oligonucleotide suppressed C2-potentiated C/EBP beta expression, indicating that AP-1 was responsible for C2-mediated C/EBP beta expression. These results demonstrate that C2 increases C/EBP beta-mediated COX-2 induction by LPS and that the pathway of JNK1 but not ERK1/2 is responsible for C/EBP beta activation involving activator protein-1-mediated enhanced C/EBP beta expression.
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PMID:Potentiation of lipopolysaccharide-inducible cyclooxygenase 2 expression by C2-ceramide via c-Jun N-terminal kinase-mediated activation of CCAAT/enhancer binding protein beta in macrophages. 1260 57

Neutrophil-specific granule deficiency involves inheritance of germline mutations in the CCAAT/enhancer-binding protein epsilon (C/EBPE) gene. Humans and mice lacking active C/EBPepsilon suffer frequent bacterial infections as a result of functionally defective neutrophils and macrophages. We hypothesized that these defects reflected dysregulation of important immune response genes. To test this, gene expression differences of peritoneally derived neutrophils and macrophages from C/EBPepsilon-/- and wild-type mice were determined with DNA microarrays. Of 283 genes, 146 known genes and 21 expressed sequence tags (ESTs) were down-regulated, and 85 known genes and 31 ESTs were up-regulated in the C/EBP-/- mice. These included genes involved in cell adhesion/chemotaxis, cytoskeletal organization, signal transduction, and immune/inflammatory responses. The cytokines CC chemokine ligand 4, CXC chemokine ligand 2, and interleukin (IL)-6, as well as cytokine receptors IL-8RB and granulocyte-colony stimulating factor, were down-regulated. Chromatin immunoprecipitation analysis identified binding of C/EBPepsilon to their promoter regions. Increased expression for lipid metabolism genes apolipoprotein E (APOE), scavenger receptor class B-1, sorting protein-related receptor containing low-density lipoprotein receptor class A repeat 1, and APOC2 in the C/EBPepsilon-/- mice correlated with reduced total cholesterol levels in these mice before and after maintenance on a high-fat diet. Also, C/EBPepsilon-deficient macrophages showed a reduced capacity to accumulate lipids. In summary, dysregulation of numerous, novel C/EBPepsilon target genes impairs innate immune response and possibly other important biological processes mediated by neutrophils and macrophages.
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PMID:Aberrant expression of neutrophil and macrophage-related genes in a murine model for human neutrophil-specific granule deficiency. 1620 33

C/EBP epsilon is a transcription factor involved in myeloid cell differentiation. Along with C/EBP-alpha, -beta, -gamma, -delta, and -zeta, C/EBP-epsilon belongs to the family of CCAAT/enhancer binding proteins that are implicated in control of growth and differentiation of several cell lineages in inflammation and stress response. We have previously shown that C/EBP-epsilon preferentially binds DNA as a heterodimer with other C/EBP family members such as C/EBP-delta, CHOP (C/EBP-zeta), and the b-zip family protein ATF4. In this study, we define the consensus binding sites for C/EBP-epsilon dimers and C/EBP-epsilon-ATF4 heterodimers. We show that the activated NFkappaB pathway promotes interaction of the C/EBP-epsilon subunit with its cognate DNA binding site via interaction with RelA. RelA-C/EBP interaction is enhanced by phosphorylation of threonine at amino acid 75 and results in increased DNA binding compared with the wild-type nonphosphorylated C/EBP both in vitro and in vivo. We suggest that interaction of the activated NFkappaB pathway and C/EBP-epsilon may be important in selective activation of a subset of C/EBP-epsilon-responsive genes.
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PMID:Modulation of DNA binding properties of CCAAT/enhancer binding protein epsilon by heterodimer formation and interactions with NFkappaB pathway. 1725 62

CCAAT enhancer-binding protein-epsilon (C/EBP-epsilon) is required for the terminal differentiation of neutrophils and eosinophils. Human C/EBP-epsilon is expressed as 4 isoforms (32, 30, 27, and 14 kDa) through differential RNA splicing, and alternative promoters and translational start sites. The C/EBP-epsilon(32/30) isoforms are transcriptional activators, whereas C/EBP-epsilon(27) interacts with and represses GATA-1 transactivation of eosinophil promoters. C/EBP-epsilon(14) contains only DNA-binding and -dimerization domains and may function as a dominant-negative regulator. To define functional activities for these C/EBP-epsilon isoforms in myelopoiesis, human CD34(+) progenitors were transduced with internal ribosomal entry site-enhanced green fluorescent protein retroviral vectors encoding the 32/30, 27, and 14-kDa isoforms, purified by fluorescence-activated cell sorter, and analyzed in colony-forming assays and suspension cultures. Progenitors transduced with C/EBP-epsilon(32/30) default exclusively to eosinophil differentiation and gene expression, independent of interleukin-5, and regardless of inclusion of cytokines to induce other lineages. In contrast, the putative repressor C/EBP-epsilon(27) isoform strongly inhibits eosinophil differentiation and gene expression, including GATA-1, promoting granulocyte (neutrophil)-macrophage differen-tiation. The C/EBP-epsilon(14) repressor isoform strongly inhibits eosinophil development and gene expression, promoting erythroid differentiation, an effect enhanced by erythropoietin. Thus, C/EBP-epsilon isoforms can reprogram myeloid lineage commitment and differentiation consistent with their predicted activities based on activator and repressor domains and in vitro functional activities.
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PMID:Human C/EBP-epsilon activator and repressor isoforms differentially reprogram myeloid lineage commitment and differentiation. 1883 58


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