scholarly journals Coordination of erythropoiesis by the transcription factor c-Myb

Blood ◽  
2006 ◽  
Vol 107 (12) ◽  
pp. 4703-4710 ◽  
Author(s):  
Alexandros Vegiopoulos ◽  
Paloma García ◽  
Nikla Emambokus ◽  
Jon Frampton
Keyword(s):  
Transcription Factor ◽  
Critical Role ◽  
Leukemia Cell ◽  
Erythroid Cell ◽  
Erythroid Progenitors ◽  
Aberrant Expression ◽  
Protein Levels ◽  
Kit Receptor ◽  
Erythroid Cell Differentiation ◽  
Factor C

Abstract The involvement of the transcription factor c-Myb in promoting the proliferation and inhibition of erythroid cell differentiation has been established in leukemia cell models. The anemia phenotype observed in c-myb knockout and knockdown mice highlights a critical role for c-Myb in erythropoiesis. However, determining the reason for the failure of erythropoiesis in these mice and the precise function of c-Myb in erythroid progenitors remains elusive. We examined erythroid development under conditions of reduced c-Myb protein levels and report an unexpected role for c-Myb in the promotion of commitment to the erythroid lineage and progression to erythroblast stages. c-myb knockdown erythroid colony-forming unit (CFU-E) stage progenitors displayed an immature phenotype and aberrant expression of several hematopoietic regulators. To extend our findings, we analyzed the response of normal enriched erythroid progenitors to inducible disruption of a floxed c-myb allele. In agreement with the c-myb knockdown phenotype, we show that c-Myb is strictly required for expression of the c-Kit receptor in erythroid cells.

scholarly journals Astrocyte-specific deletion of the transcription factor Yin Yang 1 in murine substantia nigra mitigates manganese-induced dopaminergic neurotoxicity

2020 ◽  
Vol 295 (46) ◽  
pp. 15662-15676 ◽  
Author(s):  
Edward Pajarillo ◽  
James Johnson ◽  
Asha Rizor ◽  
Ivan Nyarko-Danquah ◽  
Getinet Adinew ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Substantia Nigra ◽  
Critical Role ◽  
Conditional Knockout ◽  
Motor Functions ◽  
Mn Toxicity ◽  
Protein Levels ◽  
Yin Yang 1 ◽  
Yin Yang

Manganese (Mn)-induced neurotoxicity resembles Parkinson's disease (PD), but the mechanisms underpinning its effects remain unknown. Mn dysregulates astrocytic glutamate transporters, GLT-1 and GLAST, and dopaminergic function, including tyrosine hydroxylase (TH). Our previous in vitro studies have shown that Mn repressed GLAST and GLT-1 via activation of transcription factor Yin Yang 1 (YY1). Here, we investigated if in vivo astrocytic YY1 deletion mitigates Mn-induced dopaminergic neurotoxicity, attenuating Mn-induced reduction in GLAST/GLT-1 expression in murine substantia nigra (SN). AAV5-GFAP-Cre-GFP particles were infused into the SN of 8-week–old YY1flox/flox mice to generate a region-specific astrocytic YY1 conditional knockout (cKO) mouse model. 3 weeks after adeno-associated viral (AAV) infusion, mice were exposed to 330 μg of Mn (MnCl2 30 mg/kg, intranasal instillation, daily) for 3 weeks. After Mn exposure, motor functions were determined in open-field and rotarod tests, followed by Western blotting, quantitative PCR, and immunohistochemistry to assess YY1, TH, GLAST, and GLT-1 levels. Infusion of AAV5-GFAP-Cre-GFP vectors into the SN resulted in region-specific astrocytic YY1 deletion and attenuation of Mn-induced impairment of motor functions, reduction of TH-expressing cells in SN, and TH mRNA/protein levels in midbrain/striatum. Astrocytic YY1 deletion also attenuated the Mn-induced decrease in GLAST/GLT-1 mRNA/protein levels in midbrain. Moreover, YY1 deletion abrogated its interaction with histone deacetylases in astrocytes. These results indicate that astrocytic YY1 plays a critical role in Mn-induced neurotoxicity in vivo, at least in part, by reducing astrocytic GLAST/GLT-1. Thus, YY1 might be a potential target for treatment of Mn toxicity and other neurological disorders associated with dysregulation of GLAST/GLT-1.

scholarly journals Phosphorylation status of transcription factor C/EBPα determines cell-surface poly-LacNAc branching (I antigen) formation in erythropoiesis and granulopoiesis

Blood ◽  
2010 ◽  
Vol 115 (12) ◽  
pp. 2491-2499 ◽  
Author(s):  
Yuh-Ching Twu ◽  
Chuang-Yi Hsieh ◽  
Marie Lin ◽  
Cheng-Hwai Tzeng ◽  
Chien-Feng Sun ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Cell Surface ◽  
Cell Model ◽  
Critical Role ◽  
Erythroid Differentiation ◽  
Common Mechanism ◽  
Group I ◽  
Enhancer Binding Protein ◽  
Factor C ◽  
Granulopoietic Progenitor Cells

The cell-surface straight and branched repeats of N-acetyllactosamine (LacNAc) units, called poly-LacNAc chains, characterize the histo-blood group i and I antigens, respectively. The transition of straight to branched poly-LacNAc chain (i to I) is determined by the I locus, which expresses 3 IGnT transcripts, IGnTA, IGnTB, and IGnTC. Our previous investigation demonstrated that the i-to-I transition in erythroid differentiation is regulated by the transcription factor CCAAT/enhancer binding protein α (C/EBPα). In the present investigation, the K-562 cell line was used as a model to show that the i-to-I transition is determined by the phosphorylation status of the C/EBPα Ser-21 residue, with dephosphorylated C/EBPα Ser-21 stimulating the transcription of the IGnTC gene, consequently resulting in I branching. Results from studies using adult erythropoietic and granulopoietic progenitor cells agreed with those derived using the K-562 cell model, with lentiviral expression of C/EBPα in CD34+ hematopoietic cells demonstrating that the dephosphorylated form of C/EBPα Ser-21 induced the expression of I antigen, granulocytic CD15, and also erythroid CD71 antigens. Taken together, these results demonstrate that the regulation of poly-LacNAc branching (I antigen) formation in erythropoiesis and granulopoiesis share a common mechanism, with dephosphorylation of the Ser-21 residue on C/EBPα playing the critical role.

Myeloid Transcription Factor C/EBPɛ Is Involved in the Positive Regulation of Lactoferrin Gene Expression in Neutrophils

Blood ◽  
1999 ◽  
Vol 94 (9) ◽  
pp. 3141-3150 ◽  
Author(s):  
Walter Verbeek ◽  
Julie Lekstrom-Himes ◽  
Dorothy J. Park ◽  
Pham My-Chan Dang ◽  
Peter T. Vuong ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Transcription Factor ◽  
Bone Marrow Cells ◽  
Granulocytic Differentiation ◽  
Direct Role ◽  
Gram Negative ◽  
Protein Levels ◽  
Factor C ◽  
Marrow Cells

Abstract Targeted mutation of the myeloid transcription factor C/EBPɛ in mice results in gram-negative septic death at 3 to 5 months of age. This study defines the underlying molecular defects in their terminal granulocytic differentiation. The mRNA for the precursor protein of the cathelin-related antimicrobial peptides was almost completely absent in the bone marrow cells of C/EBPɛ−/− mice. This finding may help explain their susceptibility to gram-negative sepsis, because both are bacteriocidal peptides with potent activity against gram-negative bacteria. Superoxide production was found to be reduced in both granulocytes and monocytes of C/EBPɛ−/− mice. While gp91 phox protein levels were normal, p47phox protein levels were considerably reduced in C/EBPɛ −/− granulocytes/monocytes, possibly limiting the assembly of the NADPH oxidase. In addition, expression of mRNA of the secondary and tertiary granule proteins, lactoferrin and gelatinase, were not detected, and levels of neutrophil collagenase mRNA were reduced in bone marrow cells of the knock-out mice. The murine lactoferrin promoter has a putative C/EBP site close to the transcription start site. C/EBPɛ bound to this site in electromobility shift assay studies and mutation of this site abrogated binding to it. A mutation in the C/EBP site reduced the activity of the promoter by 35%. Furthermore, overexpression of C/EBPɛ in U937 cells increased the activity of the wild-type lactoferrin promoter by 3-fold. In summary, our data implicate C/EBPɛ as a critical factor of host antimicrobial defense and suggests that it has a direct role as a positive regulator of expression of lactoferrin in vivo.

scholarly journals Detection in non-erythroid cells of a factor with the binding characteristics of the erythroid cell transcription factor EF1

1990 ◽  
Vol 269 (2) ◽  
pp. 543-545
Author(s):  
N D Perkins ◽  
K H Orchard ◽  
M L K Collins ◽  
D S Latchman ◽  
G H Goodwin
Keyword(s):  
Transcription Factor ◽  
Dna Binding ◽  
Critical Role ◽  
Cell Types ◽  
Erythroid Cell ◽  
Erythroid Cells ◽  
First Report ◽  
Binding Characteristics

The erythroid transcription factor erythroid factor-1 (EF1) plays a critical role in the transcription of erythroid-specific genes. Here we report the presence of a factor with the mobility and sequence-specific DNA-binding characteristics of EF1 at low abundance in a wide variety of non-erythroid cell types. This is the first report of an EF1-like activity in non-erythroid cells and indicates that this factor may play a role in the regulation of genes expressed in such cells.

HSP27 controls GATA-1 protein level during erythroid cell differentiation

Blood ◽  
2010 ◽  
Vol 116 (1) ◽  
pp. 85-96 ◽  
Author(s):  
Aurelie de Thonel ◽  
Julie Vandekerckhove ◽  
David Lanneau ◽  
Subramaniam Selvakumar ◽  
Geneviève Courtois ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Ex Vivo ◽  
Apoptotic Cell ◽  
Erythroid Differentiation ◽  
Proteasomal Degradation ◽  
Fine Tuning ◽  
Erythroid Cell ◽  
Dependent Manner ◽  
Cellular Expression ◽  
Erythroid Cell Differentiation

Abstract Heat shock protein 27 (HSP27) is a chaperone whose cellular expression increases in response to various stresses and protects the cell either by inhibiting apoptotic cell death or by promoting the ubiquitination and proteasomal degradation of specific proteins. Here, we show that globin transcription factor 1 (GATA-1) is a client protein of HSP27. In 2 models of erythroid differentiation; that is, in the human erythroleukemia cell line, K562 induced to differentiate into erythroid cells on hemin exposure and CD34+ human cells ex vivo driven to erythroid differentiation in liquid culture, depletion of HSP27 provokes an accumulation of GATA-1 and impairs terminal maturation. More specifically, we demonstrate that, in the late stages of the erythroid differentiation program, HSP27 is phosphorylated in a p38-dependent manner, enters the nucleus, binds to GATA-1, and induces its ubiquitination and proteasomal degradation, provided that the transcription factor is acetylated. We conclude that HSP27 plays a role in the fine-tuning of terminal erythroid differentiation through regulation of GATA-1 content and activity.

scholarly journals Polyamines Regulate the Stability of Activating Transcription Factor-2 mRNA through RNA-binding Protein HuR in Intestinal Epithelial Cells

2007 ◽  
Vol 18 (11) ◽  
pp. 4579-4590 ◽  
Author(s):  
Lan Xiao ◽  
Jaladanki N. Rao ◽  
Tongtong Zou ◽  
Lan Liu ◽  
Bernard S. Marasa ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Rna Binding ◽  
Binding Protein ◽  
Critical Role ◽  
Rna Binding Protein ◽  
Gene Promoter ◽  
Protein Levels ◽  
Ribonucleoprotein Complexes ◽  
Activating Transcription Factor ◽  
The Stability

Maintenance of intestinal mucosal epithelial integrity requires polyamines that modulate the expression of various genes involved in cell proliferation and apoptosis. Recently, polyamines were shown to regulate the subcellular localization of the RNA-binding protein HuR, which stabilizes its target transcripts such as nucleophosmin and p53 mRNAs. The activating transcription factor-2 (ATF-2) mRNA encodes a member of the ATF/CRE-binding protein family of transcription factors and was computationally predicted to be a target of HuR. Here, we show that polyamines negatively regulate ATF-2 expression posttranscriptionally and that polyamine depletion stabilizes ATF-2 mRNA by enhancing the interaction of the 3′-untranslated region (UTR) of ATF-2 with cytoplasmic HuR. Decreasing cellular polyamines by inhibiting ornithine decarboxylase (ODC) with α-difluoromethylornithine increased the levels of ATF-2 mRNA and protein, whereas increasing polyamines by ectopic ODC overexpression repressed ATF-2 expression. Polyamine depletion did not alter transcription via the ATF-2 gene promoter but increased the stability of ATF-2 mRNA. Increased cytoplasmic HuR in polyamine-deficient cells formed ribonucleoprotein complexes with the endogenous ATF-2 mRNA and specifically bound to 3′-UTR of ATF-2 mRNA on multiple nonoverlapping 3′-UTR segments. Adenovirus-mediated HuR overexpression elevated ATF-2 mRNA and protein levels, whereas HuR silencing rendered the ATF-2 mRNA unstable and prevented increases in ATF-2 mRNA and protein. Furthermore, inhibition of ATF-2 expression prevented the increased resistance of polyamine-deficient cells to apoptosis induced by treatment with tumor necrosis factor-α and cycloheximide. These results indicate that polyamines modulate the stability of ATF-2 mRNA by altering cytoplasmic HuR levels and that polyamine-modulated ATF-2 expression plays a critical role in regulating epithelial apoptosis.

scholarly journals Escherichia coli Enterotoxin B Subunit Triggers Apoptosis of CD8+ T Cells by Activating Transcription Factor c-Myc

2001 ◽  
Vol 69 (8) ◽  
pp. 4923-4930 ◽  
Author(s):  
Marco Soriani ◽  
Neil A. Williams ◽  
Timothy R. Hirst
Keyword(s):  
Escherichia Coli ◽  
T Cells ◽  
Transcription Factor ◽  
Receptor Binding ◽  
Protein Levels ◽  
B Subunit ◽  
Heat Labile ◽  
Activating Transcription Factor ◽  
Induced Apoptosis ◽  
Factor C

ABSTRACT Heat-labile enterotoxin from enterotoxinogenic Escherichia coli is not only an important cause of diarrhea in humans and domestic animals but also possesses potent immunomodulatory properties. Recently, the nontoxic, receptor-binding B subunit of heat-labile enterotoxin (EtxB) was found to induce the selective death of CD8+ T cells, suggesting that EtxB may trigger activation of proapoptotic signaling pathways. Here we show that EtxB treatment of CD8+ T cells but not of CD4+ T cells triggers the specific up-regulation of the transcription factorc-myc, implicated in the control of cell proliferation, differentiation, and death. A concomitant elevation in Myc protein levels was also evident, with peak expression occurring 4 h posttreatment. Preincubation with c-myc antisense oligodeoxynucleotides demonstrated that Myc expression was necessary for EtxB-mediated apoptosis. Myc activation was also associated with an increase of IκBα turnover, suggesting that elevated Myc expression may be dependent on NF-κB. When CD8+ T cells were pretreated with inhibitors of IκBα turnover and NF-κB translocation, this resulted in a marked reduction in both EtxB-induced apoptosis and Myc expression. Further, a non-receptor-binding mutant of EtxB, EtxB(G33D), was shown to lack the capacity to activate Myc transcription. These findings provide further evidence that EtxB is a signaling molecule that triggers activation of transcription factors involved in cell survival.

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