A Possible Mechanism for Synergy in Transcriptional Activation between AML1 and PU.1: Exclusion of the Co-Repressor CBFA2T3 (ETO-2, MTG16).

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 3545-3545
Author(s):  
Kristine Baraoidan ◽  
Vinzon Ibanez ◽  
Chetna Mittal ◽  
Habte Yimer ◽  
Suman Chakraborty ◽  
...  
Keyword(s):  
Acute Myeloid Leukemia ◽  
Transcriptional Activation ◽  
Binding Sites ◽  
Myeloid Leukemia ◽  
Chromosomal Translocation ◽  
Hematopoietic Differentiation ◽  
Runt Domain ◽  
C Terminus ◽  
Repressor Complex ◽  
Acute Myeloid

Abstract AML1 and PU.1, important regulators of hematopoietic differentiation, interact with each other and are known to synergize in transcriptional activation (Zhang et al, 1996). PU.1 and AML1 also interact with mSin3, a component of a co-repressor complex that can include N-CoR, HDAC and CBFA2T1 (ETO, MTG8) or CBFA2T3 (ETO2, MTG16). CBFA2T3 is highly expressed in hematopoietic cells and is a target of a chromosomal translocation found in acute myeloid leukemia (t(16;21)). In transfected 293T cells, we demonstrate that both AML1 and PU.1 co-immunoprecipitate with the conserved N-terminal TAFH domain of CBFA2T3 but not the C-terminal MYND domain. Although AML1 and PU.1 independently co-immunoprecipitate with CBFA2T3, when all three proteins are over-expressed in 293T cells, AML1 and PU.1 co-immunoprecipitate with each other while excluding CBFA2T3. CBFA2T3 interacts with the non-runt portion of AML1 (AML1 C-terminus) while PU.1 can interact with both the runt domain of AML1 and AML1 C-terminus. Presumably, the interaction between AML1 and PU.1 shields the CBFA2T3 binding sites on both proteins. Since this region includes the binding site for mSin3, other co-repressors may also be excluded from an AML1/PU.1 complex. This may be one basis for the co-operation between AML1 and PU.1 in transcriptional activation.

Concurrent transcriptional deregulation of AML1/RUNX1 and GATA factors by the AML1-TRPS1 chimeric gene in t(8;21)(q24;q22) acute myeloid leukemia

Blood ◽  
2007 ◽  
Vol 109 (9) ◽  
pp. 4023-4027 ◽  
Author(s):  
Norio Asou ◽  
Masatoshi Yanagida ◽  
Liqun Huang ◽  
Masayuki Yamamoto ◽  
Katsuya Shigesada ◽  
...  
Keyword(s):  
Acute Myeloid Leukemia ◽  
Myeloid Leukemia ◽  
Chimeric Gene ◽  
Runt Domain ◽  
Hematopoietic Stem ◽  
Gata Factors ◽  
C Terminus ◽  
Dna Binding Sites ◽  
Transcriptional Deregulation ◽  
Acute Myeloid

Abstract The Runt domain transcription factor AML1/RUNX1 is essential for the generation of hematopoietic stem cells and is the most frequent target of chromosomal translocations associated with leukemia. Here, we present a new AML1 translocation found in a patient with acute myeloid leukemia M4 with t(8;21)(q24;q22) at the time of relapse. This translocation generated an in-frame chimeric gene consisting of the N-terminal portion of AML1, retaining the Runt domain, fused to the entire length of TRPS1 on the C-terminus. TRPS1 encodes a putative multitype zinc finger (ZF) protein containing 9 C2H2 type ZFs and 1 GATA type ZF. AML1-TRPS1 stimulated proliferation of hematopoietic colony-forming cells and repressed the transcriptional activity of AML1 and GATA-1 by 2 different mechanisms: competition at their cognate DNA-binding sites and physical sequestrations of AML1 and GATA-1, suggesting that simultaneous deregulation of AML1 and GATA factors constitutes a basis for leukemogenesis.

scholarly journals ETO/MTG8 Is an Inhibitor of C/EBPβ Activity and a Regulator of Early Adipogenesis

2004 ◽  
Vol 24 (22) ◽  
pp. 9863-9872 ◽  
Author(s):  
Justin J. Rochford ◽  
Robert K. Semple ◽  
Matthias Laudes ◽  
Keith B. Boyle ◽  
Constantinos Christodoulides ◽  
...  
Keyword(s):  
Gene Expression ◽  
Acute Myeloid Leukemia ◽  
Transcriptional Activation ◽  
Myeloid Leukemia ◽  
Chromosomal Translocation ◽  
Transcriptional Corepressor ◽  
Adipogenic Gene ◽  
First Time ◽  
Acute Myeloid

ABSTRACT The putative transcriptional corepressor ETO/MTG8 has been extensively studied due to its involvement in a chromosomal translocation causing the t(8;21) form of acute myeloid leukemia. Despite this, the role of ETO in normal physiology has remained obscure. Here we show that ETO is highly expressed in preadipocytes and acts as an inhibitor of C/EBPβ during early adipogenesis, contributing to its characteristically delayed activation. ETO prevents both the transcriptional activation of the C/EBPα promoter by C/EBPβ and its concurrent accumulation in centromeric sites during early adipogenesis. ETO expression rapidly reduces after the initiation of adipogenesis, and this is essential to the normal induction of adipogenic gene expression. These findings define, for the first time, a molecular role for ETO in normal physiology as an inhibitor of C/EBPβ and a novel regulator of early adipogenesis.

scholarly journals The possible significance of trisomy 8 in acute myeloid leukemia

2017 ◽  
Vol 5 (6) ◽  
pp. 2652 ◽  
Author(s):  
Salil N. Vaniawala ◽  
Monika V. Patel ◽  
Pratik D. Chavda ◽  
Shivangi H. Zaveri ◽  
Pankaj K. Gadhia
Keyword(s):  
Acute Myeloid Leukemia ◽  
Chromosomal Aberrations ◽  
Myeloid Leukemia ◽  
Chromosomal Abnormalities ◽  
Prognostic Significance ◽  
Chromosomal Translocation ◽  
Banding Technique ◽  
Trisomy 8 ◽  
Increased Risk ◽  
Acute Myeloid

Background: Acute myeloid leukemia (AML) is a heterogeneous disorder that results from a block in the differentiation of haematopoietic progenitor cells along with uncontrolled proliferation. Trisomy 8 is the most common recurring numerical chromosomal aberrations in acute myeloid leukemia (AML). It occurs either as a sole anomaly or together with other additional chromosomal aberrations. The prognostic significance of trisomy 8 in presence of other additional chromosomal abnormality depends on clonal cytogenetic changes. The patients with trisomy 8 had shorter survival with significantly increased risk with other chromosomal abnormality.Methods: Total 139 patients were screened between January 2016 to November 2016 who were suspected of AML cases. Bone marrow cultures were set up using conventional cytogenetic methods. Chromosomal preparation was made and subjected to GTG banding technique. Banded metaphases were analysed and karyotyped for further analysis.Results: Cytogenetic evaluation of karyotyped of 139 suspected AML patients showed 52 with t(8;21)(q22;q22), 36 with t(15;17)(q22;q12), and 11 with inv(16)(p13;q22). The rest 40 cases found with additional chromosomal abnormalities, of which 16 were sole trisomy 8 and 24 cases were found with other chromosomal abnormalities In addition, only one person found with t(8;21) and trisomy 8, while  three person having t(15;17) with trisomy 8.Conclusions: AML is considered to be one of the most important cytogenetic prognostic determinants. Recurrent chromosomal translocation with trisomy 8 varying 1.9% for t(8;21) and 8.3% for t(15;17). In the present study trisomy 8 in AML with known favourable anomalies is very small. Therefore, it cannot be taken as a prognostic marker.

scholarly journals WTIP upregulates FOXO3a and induces apoptosis through PUMA in acute myeloid leukemia

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Yunqi Zhu ◽  
Xiangmin Tong ◽  
Ying Wang ◽  
Xiaoya Lu
Keyword(s):  
Acute Myeloid Leukemia ◽  
Tumor Suppressor ◽  
Transcriptional Activation ◽  
Myeloid Leukemia ◽  
Molecular Mechanisms ◽  
Nuclear Translocation ◽  
Hematologic Malignancy ◽  
Apoptotic Pathway ◽  
Acute Myeloid

AbstractAcute myeloid leukemia (AML) is an aggressive and heterogeneous clonal hematologic malignancy for which novel therapeutic targets and strategies are required. Emerging evidence suggests that WTIP is a candidate tumor suppressor. However, the molecular mechanisms of WTIP in leukemogenesis have not been explored. Here, we report that WTIP expression is significantly reduced both in AML cell lines and clinical specimens compared with normal controls, and low levels of WTIP correlate with decreased overall survival in AML patients. Overexpression of WTIP inhibits cell proliferation and induces apoptosis both in vitro and in vivo. Mechanistic studies reveal that the apoptotic function of WTIP is mediated by upregulation and nuclear translocation of FOXO3a, a member of Forkhead box O (FOXO) transcription factors involved in tumor suppression. We further demonstrate that WTIP interacts with FOXO3a and transcriptionally activates FOXO3a. Upon transcriptional activation of FOXO3a, its downstream target PUMA is increased, leading to activation of the intrinsic apoptotic pathway. Collectively, our results suggest that WTIP is a tumor suppressor and a potential target for therapeutic intervention in AML.

scholarly journals Rapid detection of chromosomal translocation and precise breakpoint characterization in acute myeloid leukemia by nanopore long-read sequencing

2019 ◽  
Vol 239 ◽  
pp. 22-25 ◽  
Author(s):  
Chun Hang Au ◽  
Dona N. Ho ◽  
Beca B.K. Ip ◽  
Thomas S.K. Wan ◽  
Margaret H.L. Ng ◽  
...  
Keyword(s):  
Acute Myeloid Leukemia ◽  
Rapid Detection ◽  
Myeloid Leukemia ◽  
Chromosomal Translocation ◽  
Long Read ◽  
Acute Myeloid

The AF10 leucine zipper is required for leukemic transformation of myeloid progenitors by MLL-AF10

Blood ◽  
2002 ◽  
Vol 99 (10) ◽  
pp. 3780-3785 ◽  
Author(s):  
Jorge F. DiMartino ◽  
Paul M. Ayton ◽  
Everett H. Chen ◽  
Clarissa C. Naftzger ◽  
Bryan D. Young ◽  
...  
Keyword(s):  
Acute Myeloid Leukemia ◽  
Amino Acid ◽  
Transcriptional Activation ◽  
Myeloid Leukemia ◽  
Leucine Zipper ◽  
Function Analysis ◽  
General Mechanism ◽  
Helical Domain ◽  
Acute Myeloid ◽  
Myeloid Progenitors

The t(10;11)(p12;q23) chromosomal translocation in human acute myeloid leukemia results in the fusion of theMLL and AF10 genes. The latter codes for a novel leucine zipper protein, one of many MLL fusion partners of unknown function. In this report, we demonstrate that retroviral-mediated transduction of an MLL-AF10complementary DNA into primary murine myeloid progenitors enhanced their clonogenic potential in serial replating assays and led to their efficient immortalization at a primitive stage of myeloid differentiation. Furthermore, MLL-AF10–transduced cells rapidly induced acute myeloid leukemia in syngeneic or severe combined immunodeficiency recipient mice. Structure/function analysis showed that a highly conserved 82–amino acid portion of AF10, comprising 2 adjacent α-helical domains, was sufficient for immortalizing activity when fused to MLL. Neither helical domain alone mediated immortalization, and deletion of the 29–amino acid leucine zipper within this region completely abrogated transforming activity. Similarly, the minimal oncogenic domain of AF10 exhibited transcriptional activation properties when fused to the MLL or GAL4 DNA-binding domains, while neither helical domain alone did. However, transcriptional activation per se was not sufficient because a second activation domain of AF10 was neither required nor competent for transformation. The requirement for α-helical transcriptional effector domains is similar to the oncogenic contributions of unrelated MLL partners ENL and ELL, suggesting a general mechanism of myeloid leukemogenesis by a subset of MLL fusion proteins, possibly through specific recruitment of the transcriptional machinery.

scholarly journals Conditional MN1-TEL knock-in mice develop acute myeloid leukemia in conjunction with overexpression of HOXA9

Blood ◽  
2005 ◽  
Vol 106 (13) ◽  
pp. 4269-4277 ◽  
Author(s):  
Hiroyuki Kawagoe ◽  
Gerard C. Grosveld
Keyword(s):  
Acute Myeloid Leukemia ◽  
Myeloid Leukemia ◽  
Chromosomal Translocation ◽  
Lymphoid Cells ◽  
Dependent Manner ◽  
Myeloproliferative Disease ◽  
Long Latency ◽  
Acute Myeloid

The chromosomal translocation t(12; 22)(p13;q11) in human myeloid leukemia generates an MN1-TEL (meningioma 1-translocation-ETS-leukemia) fusion oncoprotein. This protein consists of N-terminal MN1 sequences, a transcriptional coactivator fused to C-terminal TEL sequences, an ETS (E26 transformation-specific) transcription factor. Enforced expression of MN1-TEL in multipotent hematopoietic progenitors in knock-in mice perturbed growth and differentiation of myeloid as well as lymphoid cells. Depending on obligatory secondary mutations, these mice developed T-cell lympholeukemia. Here we addressed the role of MN1-TEL in myeloid leukemogenesis using the same mouse model. Expression of MN1-TEL enhanced the growth of myeloid progenitors in an interleukin 3/stem cell factor (IL-3/SCF)–dependent manner in vitro whereas 10% of MN1-TEL–expressing mice developed altered myelopoiesis with severe anemia after long latency. Coexpression of MN1-TEL and IL-3, but not SCF, rapidly caused a fatal myeloproliferative disease rather than acute myeloid leukemia (AML). Because MN1-TEL+ AML patient cells overexpress HOXA9 (homeobox A9), we tested the effect of coexpression of MN1-TEL and HOXA9 in mice and found that 90% of MN1-TEL+/HOXA9+ mice developed AML much more rapidly than control HOXA9+ mice. Thus, the leukemogenic effect of MN1-TEL in our knock-in mice is pleiotropic, and the type of secondary mutation determines disease outcome.

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