Differential regulation of granulopoiesis by the basic helix-loop-helix transcriptional inhibitors Id1 and Id2

Blood ◽  
2005 ◽  
Vol 105 (11) ◽  
pp. 4272-4281 ◽  
Author(s):  
Miranda Buitenhuis ◽  
Hanneke W. M. van Deutekom ◽  
Liesbeth P. Verhagen ◽  
Anders Castor ◽  
Sten Eirik W. Jacobsen ◽  
...  
Keyword(s):  
Critical Role ◽  
Ectopic Expression ◽  
Constitutive Expression ◽  
Retroviral Transduction ◽  
Basic Helix Loop Helix ◽  
Helix Loop Helix ◽  
Cd34 Cells ◽  
Final Maturation ◽  
Inhibitor Of Dna Binding

Abstract Inhibitor of DNA binding (Id) proteins function as inhibitors of members of the basic helix-loop-helix family of transcription factors and have been demonstrated to play an important role in regulating lymphopoiesis. However, the role of these proteins in regulation of myelopoiesis is currently unclear. In this study, we have investigated the role of Id1 and Id2 in the regulation of granulopoiesis. Id1 expression was initially up-regulated during early granulopoiesis, which was then followed by a decrease in expression during final maturation. In contrast, Id2 expression was up-regulated in terminally differentiated granulocytes. In order to determine whether Id expression plays a critical role in regulating granulopoiesis, Id1 and Id2 were ectopically expressed in CD34+ cells by retroviral transduction. Our experiments demonstrate that constitutive expression of Id1 inhibits eosinophil development, whereas in contrast neutrophil differentiation was modestly enhanced. Constitutive Id2 expression accelerates final maturation of both eosinophils and neutrophils, whereas inhibition of Id2 expression blocks differentiation of both lineages. Transplantation of β2-microglobulin-/- nonobese diabetic severe combined immunodeficient (NOD/SCID) mice with CD34+ cells ectopically expressing Id1 resulted in enhanced neutrophil development, whereas ectopic expression of Id2 induced both eosinophil and neutrophil development. These data demonstrate that both Id1 and Id2 play a critical, although differential role in granulopoiesis.

scholarly journals The Basic Helix-Loop-Helix Transcription Factor Cph2 Regulates Hyphal Development in CandidaalbicansPartly via Tec1

2001 ◽  
Vol 21 (19) ◽  
pp. 6418-6428 ◽  
Author(s):  
Shelley Lane ◽  
Song Zhou ◽  
Ting Pan ◽  
Qian Dai ◽  
Haoping Liu
Keyword(s):  
Transcription Factor ◽  
Protein Kinase ◽  
Binding Sites ◽  
Regulatory Element ◽  
Ectopic Expression ◽  
Mitogen Activated Protein Kinase ◽  
Northern Analysis ◽  
Hyphal Development ◽  
Basic Helix Loop Helix ◽  
Helix Loop Helix

ABSTRACT Candida albicans undergoes a morphogenetic switch from budding yeast to hyphal growth form in response to a variety of stimuli and growth conditions. Multiple signaling pathways, including a Cph1-mediated mitogen-activated protein kinase pathway and an Efg1-mediated cyclic AMP/protein kinase A pathway, regulate the transition. Here we report the identification of a basic helix-loop-helix transcription factor of the Myc subfamily (Cph2) by its ability to promote pseudohyphal growth inSaccharomyces cerevisiae. Like sterol response element binding protein 1, Cph2 has a Tyr instead of a conserved Arg in the basic DNA binding region. Cph2 regulates hyphal development in C. albicans, ascph2/cph2 mutant strains show medium-specific impairment in hyphal development and in the induction of hypha-specific genes. However, many hypha-specific genes do not have potential Cph2 binding sites in their upstream regions. Interestingly, upstream sequences of all known hypha-specific genes are found to contain potential binding sites for Tec1, a regulator of hyphal development. Northern analysis shows that TEC1 transcription is highest in the medium in which cph2/cph2 displays a defect in hyphal development, and Cph2 is necessary for this transcriptional induction of TEC1. In vitro gel mobility shift experiments show that Cph2 directly binds to the two sterol regulatory element 1-like elements upstream of TEC1. Furthermore, the ectopic expression of TEC1 suppresses the defect ofcph2/cph2 in hyphal development. Therefore, the function of Cph2 in hyphal transcription is mediated, in part, through Tec1. We further show that this function of Cph2 is independent of the Cph1- and Efg1-mediated pathways.

scholarly journals An Examination of the Role of Transcriptional and Posttranscriptional Regulation in Rhabdomyosarcoma

2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Alexander J. Hron ◽  
Atsushi Asakura
Keyword(s):  
Skeletal Muscle ◽  
Soft Tissue ◽  
Posttranscriptional Regulation ◽  
Progenitor Cell ◽  
Treatment Options ◽  
Soft Tissue Tumors ◽  
Basic Helix Loop Helix ◽  
Helix Loop Helix ◽  
Bhlh Proteins

Rhabdomyosarcoma (RMS) is an aggressive family of soft tissue tumors that most commonly manifests in children. RMS variants express several skeletal muscle markers, suggesting myogenic stem or progenitor cell origin of RMS. In this review, the roles of both recently identified and well-established microRNAs in RMS are discussed and summarized in a succinct, tabulated format. Additionally, the subtypes of RMS are reviewed along with the involvement of basic helix-loop-helix (bHLH) proteins, Pax proteins, and microRNAs in normal and pathologic myogenesis. Finally, the current and potential future treatment options for RMS are outlined.

scholarly journals Inhibition of Tcf3 Binding by I-mfa Domain Proteins

2001 ◽  
Vol 21 (5) ◽  
pp. 1866-1873 ◽  
Author(s):  
Lauren Snider ◽  
Hilary Thirlwell ◽  
Jeffrey R. Miller ◽  
Randall T. Moon ◽  
Mark Groudine ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Wnt Signaling ◽  
Binding Sites ◽  
Ectopic Expression ◽  
Wnt Signaling Pathway ◽  
Developmental Pathways ◽  
Basic Helix Loop Helix ◽  
Helix Loop Helix ◽  
Dorsal Axis ◽  
Bhlh Proteins

ABSTRACT We have determined that I-mfa, an inhibitor of several basic helix-loop-helix (bHLH) proteins, and XIC, a Xenopusortholog of human I-mf domain-containing protein that shares a highly conserved cysteine-rich C-terminal domain with I-mfa, inhibit the activity and DNA binding of the HMG box transcription factor XTcf3. Ectopic expression of I-mfa or XIC in early Xenopus embryos inhibited dorsal axis specification, the expression of the Tcf3/β-catenin-regulated genessiamois and Xnr3, and the ability of β-catenin to activate reporter constructs driven by Lef/Tcf binding sites. I-mfa domain proteins can regulate both the Wnt signaling pathway and a subset of bHLH proteins, possibly coordinating the activities of these two critical developmental pathways.

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.

Wingless blocks bristle formation and morphogenetic furrow progression in the eye through repression of Daughterless

Development ◽  
2002 ◽  
Vol 129 (14) ◽  
pp. 3393-3402 ◽  
Author(s):  
Kenneth M. Cadigan ◽  
Austin D. Jou ◽  
Roel Nusse
Keyword(s):  
Gene Expression ◽  
Ectopic Expression ◽  
Dominant Negative ◽  
Proneural Gene ◽  
Morphogenetic Furrow ◽  
Heterologous Promoter ◽  
Basic Helix Loop Helix ◽  
Helix Loop Helix ◽  
Dominant Negative Form ◽  
Negative Form

In the developing eye, wingless activity represses proneural gene expression (and thus interommatidial bristle formation) and positions the morphogenetic furrow by blocking its initiation in the dorsal and ventral regions of the presumptive eye. We provide evidence that wingless mediates both effects, at least in part, through repression of the basic helix-loop-helix protein Daughterless. daughterless is required for high proneural gene expression and furrow progression. Ectopic expression of wingless blocks Daughterless expression in the proneural clusters. This repression, and that of furrow progression, can be mimicked by an activated form of armadillo and blocked by a dominant negative form of pangolin/TCF. Placing daughterless under the control of a heterologous promoter blocks the ability of ectopic wingless to inhibit bristle formation and furrow progression. hedgehog and decapentapleigic could not rescue the wingless furrow progression block, indicating that wingless acts downstream of these genes. In contrast, Atonal and Scute, which are thought to heterodimerize with Daughterless to promote furrow progression and bristle formation, respectively, can block ectopic wingless action. These results are summarized in a model where daughterless is a major, but probably not the only, target of wingless action in the eye.

The homeodomain-containing gene Xdbx inhibits neuronal differentiation in the developing embryo

Development ◽  
2000 ◽  
Vol 127 (13) ◽  
pp. 2945-2954 ◽  
Author(s):  
A.A. Gershon ◽  
J. Rudnick ◽  
L. Kalam ◽  
K. Zimmerman
Keyword(s):  
Neuronal Differentiation ◽  
Normal Development ◽  
Early Embryo ◽  
Neural Plate ◽  
Neural Progenitors ◽  
Expression Domain ◽  
Basic Helix Loop Helix ◽  
Helix Loop Helix ◽  
Early Neurogenesis

The development of the vertebrate nervous system depends upon striking a balance between differentiating neurons and neural progenitors in the early embryo. Our findings suggest that the homeodomain-containing gene Xdbx regulates this balance by maintaining neural progenitor populations within specific regions of the neuroectoderm. In posterior regions of the Xenopus embryo, Xdbx is expressed in a bilaterally symmetric stripe that lies at the middle of the mediolateral axis of the neural plate. This stripe of Xdbx expression overlaps the expression domain of the proneural basic/helix-loop-helix-containing gene, Xash3, and is juxtaposed to the expression domains of Xenopus Neurogenin related 1 and N-tubulin, markers of early neurogenesis in the embryo. Xdbx overexpression inhibits neuronal differentiation in the embryo and when co-injected with Xash3, Xdbx inhibits the ability of Xash3 to induce ectopic neurogenesis. One role of Xdbx during normal development may therefore be to restrict spatially neuronal differentiation within the neural plate, possibly by altering the neuronal differentiation function of Xash3.

scholarly journals Opposing effects of the basic helix-loop-helix transcription factor SCL on erythroid and monocytic differentiation

Blood ◽  
1996 ◽  
Vol 87 (1) ◽  
pp. 102-111 ◽  
Author(s):  
T Hoang ◽  
E Paradis ◽  
G Brady ◽  
F Billia ◽  
K Nakahara ◽  
...  
Keyword(s):  
Aminolevulinic Acid ◽  
Single Cells ◽  
Hematopoietic Cells ◽  
Erythroid Differentiation ◽  
Mrna Levels ◽  
Monocytic Differentiation ◽  
Basic Helix Loop Helix ◽  
Helix Loop Helix ◽  
Opposing Effects

Abstract The SCL gene (also called Tal-1 or TCL5) was identified because of its association with chromosomal translocations in childhood T-cell lymphoid leukemias. SCL codes for a basic helix-loop-helix (bHLH) factor that can function as a transcriptional activator or repressor. In the adult, SCL expression is restricted to hematopoietic cells and tissues, but its function in the process of lineage commitment is unknown. The present study was designed to address the role of SCL in hematopoietic cell differentiation. SCL expression was determined in primary hematopoietic cells through the screening of cDNA samples obtained by reverse transcription-polymerase chain reaction (RT-PCR) from single cells at different stages of differentiation. SCL RNA expression was highest in bipotential and committed erythroid precursors and diminished with subsequent maturation to proerythroblasts and normoblasts. In contrast, SCL mRNA was low to undetectable in precursors of granulocytes and monocytes and their maturing progeny. The same pattern of expression was observed after erythroid or monocytic differentiation of a bipotent cell line, TF-1, in that SCL mRNA levels remained elevated during erythroid differentiation and were downregulated with monocytic differentiation. Accordingly, TF-1 was chosen as a model to investigate the functional significance of this divergent pattern of SCL expression in the two lineages. Four independent clones stably transfected with an SCL expression vector exhibited enhanced spontaneous and delta-aminolevulinic acid-induced erythroid differentiation as measured by glycophorin expression and hemoglobinization, consistent with the view that SCL is a positive regulator of erythroid differentiation. Furthermore, constitutive SCL expression interfered with monocytic differentiation, as assessed by the generation of adherent cells and the expression of Fc gamma RII in response to TPA. These results suggest that the downregulation of SCL may be required for monocytic differentiation.

The Basic Helix-Loop-Helix TAL1/SCL and Its Partners E47 and LMO2 Act Upstream of the VE-Cadherin Gene in Endothelial Cells.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 1795-1795
Author(s):  
Virginie Deleuze ◽  
Elias Chalhoub ◽  
Rawan El-Hajj ◽  
Christiane Dohet ◽  
Mikael Le Clech ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Ectopic Expression ◽  
Cell Junctions ◽  
Small Interfering Rnas ◽  
Hek 293 ◽  
Basic Helix Loop Helix ◽  
Helix Loop Helix ◽  
Cell Cell

Abstract The basic helix-loop-helix protein TAL-1/SCL, essential for the formation of the hematopoietic system, is also required for vascular development and more particularly for embryonic angiogenesis. We previously reported that TAL-1 acts as a positive factor for post-natal angiogenesis by stimulating endothelial morphogenesis. To understand how TAL-1 modulates angiogenesis, we investigated the functional consequences of TAL-1 silencing, mediated by small-interfering RNAs, in human primary endothelial cells (ECs). We found that TAL-1 knockdown impaired in vitro EC tubulomorphogenesis (in 2-D on Matrigel or 3-D in collagen I gel), with the notable absence of cell-cell contacts, a prerequisite for morphogenesis initiation. This cellular deficiency was associated with a dramatic reduction in the vascular-endothelial (VE)-cadherin at intercellular junctions, the major component of endothelial adherens junctions. In contrast, PECAM (or CD31) was present at cell-cell junctions at the same levels as control cells. Importantly, silencing of two known TAL-1-partners in hematopoietic cells, E47 or LMO2, produce the same effects as TAL-1. Accordingly, silencing of TAL-1, as well as E47 and LMO2, provoked down-regulation of VE-cadherin at both the mRNA and protein levels. Transient transfection experiments in HUVECs showed that TAL-1 and E47 regulate the VE-cadherin promoter through a specialized E-box element. Finally, endogenous VE-cadherin transcription could be directly activated in non-endothelial HEK-293 cells that neither express TAL-1 or LMO2, by the sole concomitant ectopic expression of TAL-1, E47 and LMO2. Overall, our data demonstrate that a multiprotein complex containing at least TAL-1, LMO2 and E47 act upstream of the VE-cadherin gene. We are currently performing chromatin immunoprecipitation (ChIP) to investigate whether the TAL-1-containing complex binds in vivo the VE-cadherin promoter. This study identifies VE-cadherin as an upstream TAL-1-target gene in the endothelial lineage, and provides a first clue in TAL-1 function in the control of angiogenesis.

A Critical Role of Mir-9 in Myelopoesis and EVI1-Induced Leukemogenesis.

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 2332-2332
Author(s):  
Vitalyi Senyuk ◽  
Yunyuan Zhang ◽  
Yang Liu ◽  
Ming Ming ◽  
Jianjun Chen ◽  
...  
Keyword(s):  
Cell Transformation ◽  
Conflicts Of Interest ◽  
Critical Role ◽  
Ectopic Expression ◽  
Myeloid Differentiation ◽  
Dna Hypermethylation ◽  
Hematopoietic Stem

Abstract Abstract 2332 MicroRNA-9 (miR-9) is required for normal neurogenesis and organ development. The expression of miR-9 is altered in several types of solid tumors suggesting that it may have a function in cell transformation. However the role of this miR in normal hematopoiesis and leukemogenesis is unknown. Here we show that miR-9 is expressed at low levels in hematopoietic stem/progenitor cells (HSCs/HPCs), and that it is upregulated during hematopoietic differentiation. Ectopic expression of miR-9 strongly accelerates terminal myelopoiesis, while promoting apoptosis in vitro and in vivo. In addition, the inhibition of miR-9 in HPC with a miRNA sponge blocks myelopoiesis. EVI1, required for normal embryogenesis, and is considered an oncogene because inappropriate upregulation induces malignant transformation in solid and hematopoietic cancers. In vitro, EVI1 severely affects myeloid differentiation. Here we show that EVI1 binds to the promoter of miR-9–3 leading to DNA hypermethylation of the promoter as well as repression of miR-9. We also show that ectopic miR-9 reverses the myeloid differentiation block that is induced by EVI1. Our findings suggest that inappropriately expressed EVI1 delays or blocks myeloid differentiation, at least in part by DNA hypermethylation and downregulation of miR-9. It was previously reported that FoxOs genes inhibit myeloid differentiation and prevent differentiation of leukemia initiating cells. Here we identify FoxO3 and FoxO1 as new direct targets of miR-9 in hematopoietic cells, and we find that upregulation of FoxO3 in miR-9-positive cells reduces the acceleration of myelopoiesis. These results reveal a novel role of miR-9 in myelopoiesis and in the pathogenesis of EVI1-induced myeloid neoplasms. They also provide new insights on the potential chromatin-modifying role of oncogenes in epigenetic changes in cancer cells. Disclosures: No relevant conflicts of interest to declare.

Sign in / Sign up

Export Citation Format

Share Document