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Vasileva AN, Aleshina OA, Biderman BV, Sudarikov AB. Molecular genetic abnormalities in patients with T-cell acute lymphoblastic leukemia: a literature review. ONCOHEMATOLOGY 2022. [DOI: 10.17650/1818-8346-2022-17-4-166-176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
T-cell acute lymphoblastic leukemia/lymphoma (T-ALL) is an aggressive hematological disease. Modern polychemotherapy protocols allow achieving a 5-year overall survival of 60–90 % in different age groups, however, relapses and refractory forms of T-ALL remain incurable. Over the past decades, the pathogenesis of this variant of leukemia has been studied in many trials, and it has been found that various signaling pathways are involved in the multi-step process of leukemogenesis. This opens the way for targeted therapy.In this review, we provide an update on the pathogenesis of T-ALL, opportunities for introducing targeted therapies, and issues that remain to be addressed.
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Affiliation(s)
- A. N. Vasileva
- National Research Center for Hematology, Ministry of Health of Russia
| | - O. A. Aleshina
- National Research Center for Hematology, Ministry of Health of Russia
| | - B. V. Biderman
- National Research Center for Hematology, Ministry of Health of Russia
| | - A. B. Sudarikov
- National Research Center for Hematology, Ministry of Health of Russia
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2
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ILC Differentiation in the Thymus. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1365:25-39. [DOI: 10.1007/978-981-16-8387-9_3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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3
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Homodimeric and Heterodimeric Interactions among Vertebrate Basic Helix-Loop-Helix Transcription Factors. Int J Mol Sci 2021; 22:ijms222312855. [PMID: 34884664 PMCID: PMC8657788 DOI: 10.3390/ijms222312855] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Revised: 11/11/2021] [Accepted: 11/17/2021] [Indexed: 01/01/2023] Open
Abstract
The basic helix–loop–helix transcription factor (bHLH TF) family is involved in tissue development, cell differentiation, and disease. These factors have transcriptionally positive, negative, and inactive functions by combining dimeric interactions among family members. The best known bHLH TFs are the E-protein homodimers and heterodimers with the tissue-specific TFs or ID proteins. These cooperative and dynamic interactions result in a complex transcriptional network that helps define the cell’s fate. Here, the reported dimeric interactions of 67 vertebrate bHLH TFs with other family members are summarized in tables, including specifications of the experimental techniques that defined the dimers. The compilation of these extensive data underscores homodimers of tissue-specific bHLH TFs as a central part of the bHLH regulatory network, with relevant positive and negative transcriptional regulatory roles. Furthermore, some sequence-specific TFs can also form transcriptionally inactive heterodimers with each other. The function, classification, and developmental role for all vertebrate bHLH TFs in four major classes are detailed.
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Iacobucci I, Kimura S, Mullighan CG. Biologic and Therapeutic Implications of Genomic Alterations in Acute Lymphoblastic Leukemia. J Clin Med 2021; 10:3792. [PMID: 34501239 PMCID: PMC8432032 DOI: 10.3390/jcm10173792] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Revised: 08/16/2021] [Accepted: 08/18/2021] [Indexed: 12/13/2022] Open
Abstract
Acute lymphoblastic leukemia (ALL) is the most successful paradigm of how risk-adapted therapy and detailed understanding of the genetic alterations driving leukemogenesis and therapeutic response may dramatically improve treatment outcomes, with cure rates now exceeding 90% in children. However, ALL still represents a leading cause of cancer-related death in the young, and the outcome for older adolescents and young adults with ALL remains poor. In the past decade, next generation sequencing has enabled critical advances in our understanding of leukemogenesis. These include the identification of risk-associated ALL subtypes (e.g., those with rearrangements of MEF2D, DUX4, NUTM1, ZNF384 and BCL11B; the PAX5 P80R and IKZF1 N159Y mutations; and genomic phenocopies such as Ph-like ALL) and the genomic basis of disease evolution. These advances have been complemented by the development of novel therapeutic approaches, including those that are of mutation-specific, such as tyrosine kinase inhibitors, and those that are mutation-agnostic, including antibody and cellular immunotherapies, and protein degradation strategies such as proteolysis-targeting chimeras. Herein, we review the genetic taxonomy of ALL with a focus on clinical implications and the implementation of genomic diagnostic approaches.
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Affiliation(s)
- Ilaria Iacobucci
- Department of Pathology, St. Jude Children’s Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA;
| | - Shunsuke Kimura
- Department of Pathology, St. Jude Children’s Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA;
| | - Charles G. Mullighan
- Department of Pathology, St. Jude Children’s Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA;
- Comprehensive Cancer Center, Hematological Malignancies Program, St. Jude Children’s Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA
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5
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Bajana S, Thomas K, Georgescu C, Zhao Y, Wren JD, Kovats S, Sun XH. Augmenting E Protein Activity Impairs cDC2 Differentiation at the Pre-cDC Stage. Front Immunol 2020; 11:577718. [PMID: 33391258 PMCID: PMC7775562 DOI: 10.3389/fimmu.2020.577718] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Accepted: 11/12/2020] [Indexed: 11/24/2022] Open
Abstract
Dendritic cell (DC) specification and differentiation are controlled by a circuit of transcription factors, which regulate the expression of DC effector genes as well as the transcription factors themselves. E proteins are a widely expressed basic helix-loop-helix family of transcription factors whose activity is suppressed by their inhibitors, ID proteins. Loss-of-function studies have demonstrated the essential role of both E and ID proteins in different aspects of DC development. In this study, we employed a gain-of-function approach to illustrate the importance of the temporal control of E protein function in maintaining balanced differentiation of conventional DC (cDC) subsets, cDC1 and cDC2. We expressed an E protein mutant, ET2, which dimerizes with endogenous E proteins to overcome inhibition by ID proteins and activate the transcription of E protein targets. Induction of ET2 expression at the hematopoietic progenitor stage led to a dramatic reduction in cDC2 precursors (pre-cDC2s) with little impact on pre-cDC1s. Consequently, we observed decreased numbers of cDC2s in the spleen and lung, as well as in FLT3L-driven bone marrow-derived DC cultures. Furthermore, in mice bearing ET2, we detected increased expression of the IRF8 transcription factor in cDC2s, in which IRF8 is normally down-regulated and IRF4 up-regulated. This aberrant expression of IRF8 induced by ET2 may contribute to the impairment of cDC2 differentiation. In addition, analyses of the transcriptomes of splenic cDC1s and cDC2s revealed that ET2 expression led to a shift, at least in part, of the transcriptional profile characteristic of cDC2s to that of cDC1. Together, these results suggest that a precise control of E protein activity is crucial for balanced DC differentiation.
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Affiliation(s)
- Sandra Bajana
- Program in Arthritis and Clinical Immunology, Oklahoma Medical Research Foundation, Oklahoma City, OK, United States
| | - Kevin Thomas
- Program in Arthritis and Clinical Immunology, Oklahoma Medical Research Foundation, Oklahoma City, OK, United States
| | - Constantin Georgescu
- Program in Genes and Human Diseases, Oklahoma Medical Research Foundation, Oklahoma City, OK, United States
| | - Ying Zhao
- Program in Arthritis and Clinical Immunology, Oklahoma Medical Research Foundation, Oklahoma City, OK, United States
| | - Jonathan D. Wren
- Program in Genes and Human Diseases, Oklahoma Medical Research Foundation, Oklahoma City, OK, United States
| | - Susan Kovats
- Program in Arthritis and Clinical Immunology, Oklahoma Medical Research Foundation, Oklahoma City, OK, United States
| | - Xiao-Hong Sun
- Program in Arthritis and Clinical Immunology, Oklahoma Medical Research Foundation, Oklahoma City, OK, United States
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6
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Meyer A, Herkt S, Kunze-Schumacher H, Kohrs N, Ringleb J, Schneider L, Kuvardina ON, Oellerich T, Häupl B, Krueger A, Seifried E, Bonig H, Lausen J. The transcription factor TAL1 and miR-17-92 create a regulatory loop in hematopoiesis. Sci Rep 2020; 10:21438. [PMID: 33293632 PMCID: PMC7722897 DOI: 10.1038/s41598-020-78629-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Accepted: 11/24/2020] [Indexed: 12/16/2022] Open
Abstract
A network of gene regulatory factors such as transcription factors and microRNAs establish and maintain gene expression patterns during hematopoiesis. In this network, transcription factors regulate each other and are involved in regulatory loops with microRNAs. The microRNA cluster miR-17-92 is located within the MIR17HG gene and encodes six mature microRNAs. It is important for hematopoietic differentiation and plays a central role in malignant disease. However, the transcription factors downstream of miR-17-92 are largely elusive and the transcriptional regulation of miR-17-92 is not fully understood. Here we show that miR-17-92 forms a regulatory loop with the transcription factor TAL1. The miR-17-92 cluster inhibits expression of TAL1 and indirectly leads to decreased stability of the TAL1 transcriptional complex. We found that TAL1 and its heterodimerization partner E47 regulate miR-17-92 transcriptionally. Furthermore, miR-17-92 negatively influences erythroid differentiation, a process that depends on gene activation by the TAL1 complex. Our data give example of how transcription factor activity is fine-tuned during normal hematopoiesis. We postulate that disturbance of the regulatory loop between TAL1 and the miR-17-92 cluster could be an important step in cancer development and progression.
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Affiliation(s)
- Annekarin Meyer
- Institute for Transfusion Medicine and Immunohematology, and German Red Cross Blood Service BaWüHe, Goethe University, Sandhofstraße 1, 60528, Frankfurt, Germany
| | - Stefanie Herkt
- Institute for Transfusion Medicine and Immunohematology, and German Red Cross Blood Service BaWüHe, Goethe University, Sandhofstraße 1, 60528, Frankfurt, Germany
| | - Heike Kunze-Schumacher
- Institute for Molecular Medicine, Goethe University, Theodor-Stern-Kai 7, 60590, Frankfurt, Germany
| | - Nicole Kohrs
- Institute for Tumor Biology and Experimental Therapy, Georg-Speyer-Haus, Paul-Ehrlich-Strasse 42-44, 60596, Frankfurt am Main, Germany
| | - Julia Ringleb
- Institute for Tumor Biology and Experimental Therapy, Georg-Speyer-Haus, Paul-Ehrlich-Strasse 42-44, 60596, Frankfurt am Main, Germany
| | - Lucas Schneider
- Institute for Transfusion Medicine and Immunohematology, and German Red Cross Blood Service BaWüHe, Goethe University, Sandhofstraße 1, 60528, Frankfurt, Germany
| | - Olga N Kuvardina
- Institute for Transfusion Medicine and Immunohematology, and German Red Cross Blood Service BaWüHe, Goethe University, Sandhofstraße 1, 60528, Frankfurt, Germany
| | - Thomas Oellerich
- Department of Medicine II, Hematology/Oncology, Goethe University, Theodor-Stern-Kai 7, 60590, Frankfurt, Germany.,German Cancer Research Center and German Cancer Consortium, Heidelberg, Germany.,Frankfurt Cancer Institute, Goethe University, 60596, Frankfurt, Germany
| | - Björn Häupl
- Department of Medicine II, Hematology/Oncology, Goethe University, Theodor-Stern-Kai 7, 60590, Frankfurt, Germany.,German Cancer Research Center and German Cancer Consortium, Heidelberg, Germany.,Frankfurt Cancer Institute, Goethe University, 60596, Frankfurt, Germany
| | - Andreas Krueger
- Institute for Molecular Medicine, Goethe University, Theodor-Stern-Kai 7, 60590, Frankfurt, Germany
| | - Erhard Seifried
- Institute for Transfusion Medicine and Immunohematology, and German Red Cross Blood Service BaWüHe, Goethe University, Sandhofstraße 1, 60528, Frankfurt, Germany
| | - Halvard Bonig
- Institute for Transfusion Medicine and Immunohematology, and German Red Cross Blood Service BaWüHe, Goethe University, Sandhofstraße 1, 60528, Frankfurt, Germany.,Department of Medicine, Division of Hematology, University of Washington, Seattle, WA, 98195, USA
| | - Joern Lausen
- Institute for Transfusion Medicine and Immunohematology, and German Red Cross Blood Service BaWüHe, Goethe University, Sandhofstraße 1, 60528, Frankfurt, Germany. .,Department of Eukaryotic Genetics, Institute of Industrial Genetics, University of Stuttgart, Allmandring 31, 70569, Stuttgart, Germany.
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Berrett H, Qian L, Roman O, Cordova A, Simmons A, Sun XH, Alberola-Ila J. Development of Type 2 Innate Lymphoid Cells Is Selectively Inhibited by Sustained E Protein Activity. Immunohorizons 2019; 3:593-605. [PMID: 31852728 PMCID: PMC6938226 DOI: 10.4049/immunohorizons.1900045] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Accepted: 12/02/2019] [Indexed: 11/25/2022] Open
Abstract
Innate lymphoid cells (ILCs) are tissue-resident lymphoid cells that reside mostly at barrier surfaces and participate in the initial response against pathogens. They are classified into different types based on effector programs that are based on cytokine production and transcription factor expression. They all derive from the common lymphoid precursor, but the molecular mechanisms regulating ILC subset development is not well understood. Experiments using Id2 knockout mice have previously shown that E protein activity inhibition is an absolute requirement for the development of all ILC subsets. In this study, we use a genetic approach to demonstrate that small increases in E protein activity during ILC development selectively inhibit type 2 ILC development. Type 1 ILCs are mostly unperturbed, and type 3 ILC show only a minor inhibition. This effect is first evident at the ILC2 progenitor stage and is ILC intrinsic. Therefore, our results demonstrate that modulation of E protein activity can bias cell fate decisions in developing ILCs.
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Affiliation(s)
- Hannah Berrett
- Arthritis and Clinical Immunology Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104; and.,Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104
| | - Liangyue Qian
- Arthritis and Clinical Immunology Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104; and
| | - Olga Roman
- Arthritis and Clinical Immunology Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104; and
| | - Alanis Cordova
- Arthritis and Clinical Immunology Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104; and
| | - Amie Simmons
- Arthritis and Clinical Immunology Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104; and
| | - Xiao-Hong Sun
- Arthritis and Clinical Immunology Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104; and.,Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104
| | - José Alberola-Ila
- Arthritis and Clinical Immunology Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104; and .,Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104
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8
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Tan TK, Zhang C, Sanda T. Oncogenic transcriptional program driven by TAL1 in T-cell acute lymphoblastic leukemia. Int J Hematol 2018; 109:5-17. [PMID: 30145780 DOI: 10.1007/s12185-018-2518-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Revised: 07/21/2018] [Accepted: 08/06/2018] [Indexed: 12/12/2022]
Abstract
TAL1/SCL is a prime example of an oncogenic transcription factor that is abnormally expressed in acute leukemia due to the replacement of regulator elements. This gene has also been recognized as an essential regulator of hematopoiesis. TAL1 expression is strictly regulated in a lineage- and stage-specific manner. Such precise control is crucial for the switching of the transcriptional program. The misexpression of TAL1 in immature thymocytes leads to a widespread series of orchestrated downstream events that affect several different cellular machineries, resulting in a lethal consequence, namely T-cell acute lymphoblastic leukemia (T-ALL). In this article, we will discuss the transcriptional regulatory network and downstream target genes, including protein-coding genes and non-coding RNAs, controlled by TAL1 in normal hematopoiesis and T-cell leukemogenesis.
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Affiliation(s)
- Tze King Tan
- Cancer Science Institute of Singapore, National University of Singapore, Centre for Translational Medicine, 14 Medical Drive, #12-01, Singapore, 117599, Singapore
| | - Chujing Zhang
- Cancer Science Institute of Singapore, National University of Singapore, Centre for Translational Medicine, 14 Medical Drive, #12-01, Singapore, 117599, Singapore
| | - Takaomi Sanda
- Cancer Science Institute of Singapore, National University of Singapore, Centre for Translational Medicine, 14 Medical Drive, #12-01, Singapore, 117599, Singapore. .,Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 117599, Singapore.
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SCL, LMO1 and Notch1 reprogram thymocytes into self-renewing cells. PLoS Genet 2014; 10:e1004768. [PMID: 25522233 PMCID: PMC4270438 DOI: 10.1371/journal.pgen.1004768] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2014] [Accepted: 09/22/2014] [Indexed: 12/30/2022] Open
Abstract
The molecular determinants that render specific populations of normal cells susceptible to oncogenic reprogramming into self-renewing cancer stem cells are poorly understood. Here, we exploit T-cell acute lymphoblastic leukemia (T-ALL) as a model to define the critical initiating events in this disease. First, thymocytes that are reprogrammed by the SCL and LMO1 oncogenic transcription factors into self-renewing pre-leukemic stem cells (pre-LSCs) remain non-malignant, as evidenced by their capacities to generate functional T cells. Second, we provide strong genetic evidence that SCL directly interacts with LMO1 to activate the transcription of a self-renewal program coordinated by LYL1. Moreover, LYL1 can substitute for SCL to reprogram thymocytes in concert with LMO1. In contrast, inhibition of E2A was not sufficient to substitute for SCL, indicating that thymocyte reprogramming requires transcription activation by SCL-LMO1. Third, only a specific subset of normal thymic cells, known as DN3 thymocytes, is susceptible to reprogramming. This is because physiological NOTCH1 signals are highest in DN3 cells compared to other thymocyte subsets. Consistent with this, overexpression of a ligand-independent hyperactive NOTCH1 allele in all immature thymocytes is sufficient to sensitize them to SCL-LMO1, thereby increasing the pool of self-renewing cells. Surprisingly, hyperactive NOTCH1 cannot reprogram thymocytes on its own, despite the fact that NOTCH1 is activated by gain of function mutations in more than 55% of T-ALL cases. Rather, elevating NOTCH1 triggers a parallel pathway involving Hes1 and Myc that dramatically enhances the activity of SCL-LMO1 We conclude that the acquisition of self-renewal and the genesis of pre-LSCs from thymocytes with a finite lifespan represent a critical first event in T-ALL. Finally, LYL1 and LMO1 or LMO2 are co-expressed in most human T-ALL samples, except the cortical T subtype. We therefore anticipate that the self-renewal network described here may be relevant to a majority of human T-ALL. Deciphering the initiating events in lymphoid leukemia is important for the development of new therapeutic strategies. In this manuscript, we define oncogenic reprogramming as the process through which non-self-renewing progenitors are converted into pre-leukemic stem cells with sustained self-renewal capacities. We provide strong genetic evidence that this step is rate-limiting in leukemogenesis and requires the activation of a self-renewal program by oncogenic transcription factors, as exemplified by SCL and LMO1. Furthermore, NOTCH1 is a pathway that drives cell fate in the thymus. We demonstrate that homeostatic NOTCH1 levels that are highest in specific thymocyte subsets determine their susceptibilities to oncogenic reprogramming by SCL and LMO1. Our data provide novel insight into the acquisition of self-renewal as a critical first step in lymphoid cell transformation, requiring the synergistic interaction of oncogenic transcription factors with a cellular context controlled by high physiological NOTCH1.
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Abstract
The family of inhibitor of differentiation (Id) proteins is a group of evolutionarily conserved molecules, which play important regulatory roles in organisms ranging from Drosophila to humans. Id proteins are small polypeptides harboring a helix-loop-helix (HLH) motif, which are best known to mediate dimerization with other basic HLH proteins, primarily E proteins. Because Id proteins do not possess the basic amino acids adjacent to the HLH motif necessary for DNA binding, Id proteins inhibit the function of E protein homodimers, as well as heterodimers between E proteins and tissue-specific bHLH proteins. However, Id proteins have also been shown to have E protein-independent functions. The Id genes are broadly but differentially expressed in a variety of cell types. Transcription of the Id genes is controlled by transcription factors such as C/EBPβ and Egr as well as by signaling pathways triggered by different stimuli, which include bone morphogenic proteins, cytokines, and ligands of T cell receptors. In general, Id proteins are capable of inhibiting the differentiation of progenitors of different cell types, promoting cell-cycle progression, delaying cellular senescence, and facilitating cell migration. These properties of Id proteins enable them to play significant roles in stem cell maintenance, vasculogenesis, tumorigenesis and metastasis, the development of the immune system, and energy metabolism. In this review, we intend to highlight the current understanding of the function of Id proteins and discuss gaps in our knowledge about the mechanisms whereby Id proteins exert their diverse effects in multiple cellular processes.
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Affiliation(s)
- Flora Ling
- Immunobiology Cancer Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, USA
| | - Bin Kang
- Immunobiology Cancer Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, USA
| | - Xiao-Hong Sun
- Immunobiology Cancer Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, USA.
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11
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Hu T, Wang H, Simmons A, Bajaña S, Zhao Y, Kovats S, Sun XH, Alberola-Ila J. Increased level of E protein activity during invariant NKT development promotes differentiation of invariant NKT2 and invariant NKT17 subsets. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2013; 191:5065-73. [PMID: 24123679 PMCID: PMC3832958 DOI: 10.4049/jimmunol.1301546] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
E protein transcription factors and their natural inhibitors, Id proteins, play critical and complex roles during lymphoid development. In this article, we report that partial maintenance of E protein activity during positive selection results in a change in the cell fate determination of developing iNKT cells, with a block in the development of iNKT1 cells and a parallel increase in the iNKT2 and iNKT17 subsets. Because the expression levels of the transcription factors that drive these alternative functional fates (GATA-3, RORγT, T-bet, and Runx-3) are not altered, our results suggest that E protein activity controls a novel checkpoint that regulates the number of iNKT precursors that choose each fate.
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Affiliation(s)
| | | | | | - Sandra Bajaña
- Arthritis and Immunology Program, Oklahoma Medical Research Foundation
| | | | - Susan Kovats
- Arthritis and Immunology Program, Oklahoma Medical Research Foundation
| | - Xiao-hong Sun
- Correspondence to: Jose Alberola-Ila or Xiao-Hong Sun, Immunobiology and Cancer Research Program, Oklahoma Medical Research Foundation (OMRF), 825 N.E. 13th Street, Oklahoma City, OK 73104, ,
| | - Jose Alberola-Ila
- Correspondence to: Jose Alberola-Ila or Xiao-Hong Sun, Immunobiology and Cancer Research Program, Oklahoma Medical Research Foundation (OMRF), 825 N.E. 13th Street, Oklahoma City, OK 73104, ,
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12
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Zhang P, Zhao Y, Sun XH. Notch-regulated periphery B cell differentiation involves suppression of E protein function. THE JOURNAL OF IMMUNOLOGY 2013; 191:726-36. [PMID: 23752615 DOI: 10.4049/jimmunol.1202134] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Notch signaling pathway plays important roles in promoting the generation of marginal zone (MZ) B cells at the expense of follicular (FO) B cells during periphery B cell maturation, but the underlying molecular mechanisms are not well understood. We hypothesize that Notch favors the generation of MZ B cells by downregulating E protein activity. In this study, we demonstrated that expression of Id2 and ankyrin-repeat SOCS box-containing protein 2 was elevated in MZ B cells and by Notch signaling. Id2 inhibits the DNA binding activity of E proteins, whereas ankyrin-repeat SOCS box-containing protein 2 facilitates E protein ubiquitination. Next, we examined the phenotypes of splenic B cells in mice expressing constitutively active Notch1 and/or two gain-of-function mutants of E proteins that counteract Id2-mediated inhibition or Notch-induced degradation. We found that upregulation of E proteins promoted the formation of FO B cells, whereas it suppressed the maturation of MZ B cells. In contrast, excessive amounts of Notch1 stimulated the differentiation of MZ B cells and inhibited the production of FO B cells. More interestingly, the effects of Notch1 were reversed by gain of E protein function. Furthermore, high levels of Bcl-6 expression in FO B cells was shown to be diminished by Notch signaling and restored by E proteins. In addition, E proteins facilitated and Notch hindered the differentiation of transitional B cells. Taken together, it appears that Notch regulates peripheral B cell differentiation, at least in part, through opposing E protein function.
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Affiliation(s)
- Ping Zhang
- Immunobiology and Cancer Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA
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13
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Zhao Y, Ling F, Wang HC, Sun XH. Chronic TLR signaling impairs the long-term repopulating potential of hematopoietic stem cells of wild type but not Id1 deficient mice. PLoS One 2013; 8:e55552. [PMID: 23383338 PMCID: PMC3562238 DOI: 10.1371/journal.pone.0055552] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2012] [Accepted: 12/23/2012] [Indexed: 12/12/2022] Open
Abstract
Hematopoietic stem cells (HSCs) maintain life-long blood supply but are inevitably exposed to various inflammatory stimuli, which have been shown to be harmful for HSC integrity but the mediators of the deleterious effects have not been fully identified. Here, we show that daily injection of mice with 1 µg of LPS for 30 days triggers a storm of inflammatory cytokines. LPS injection also stimulated the transcription of the Id1 gene in HSCs in vivo but not in vitro, suggesting an indirect effect. To determine the effects of LPS treatment on HSC function and to evaluate the significance of Id1 expression, we assess the repopulating potential of wild type and Id1 deficient mice, which were subjected to a 30 day regimen of LPS treatment. We found that LPS caused dramatic reduction in the long-term but not short-term repopulating activity of wild type but not Id1 deficient HSC. This treatment also led to increases in HSC counts, decreases in BrdU-label retention and disturbance of quiescence detected by Ki67 staining in wild type but not Id1 deficient mice. Together, it appears that Id1, at least in part, plays a role in LPS-induced damage of HSC integrity.
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Affiliation(s)
- Ying Zhao
- Immunobiology and Cancer Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, United States of America
| | - Flora Ling
- Immunobiology and Cancer Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, United States of America
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
| | - Hong-Cheng Wang
- Immunobiology and Cancer Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, United States of America
| | - Xiao-Hong Sun
- Immunobiology and Cancer Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, United States of America
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
- * E-mail:
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14
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Long CL, Berry WL, Zhao Y, Sun XH, Humphrey MB. E proteins regulate osteoclast maturation and survival. J Bone Miner Res 2012; 27:2476-89. [PMID: 22807064 PMCID: PMC3495082 DOI: 10.1002/jbmr.1707] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/14/2011] [Revised: 06/14/2012] [Accepted: 06/27/2012] [Indexed: 11/08/2022]
Abstract
Osteoclasts are bone-specific polykaryons derived from myeloid precursors under the stimulation of macrophage colony stimulating factor (M-CSF) and receptor activator of NF-κB ligand (RANKL). E proteins are basic helix-loop-helix (bHLH) transcription factors that modulate lymphoid versus myeloid cell fate decisions. To study the role of E proteins in osteoclasts, myeloid-specific E protein gain-of-function transgenic mice were generated. These mice have high bone mass due to decreased osteoclast numbers and increased osteoclast apoptosis leading to overall reductions in resorptive capacity. The molecular mechanism of decreased osteoclast numbers and resorption is in part a result of elevated expression of CD38, a regulator of intracellular calcium pools with known antiosteoclastogenic properties, which increases sensitivity to apoptosis. In vivo, exogenous RANKL stimulation can overcome this inhibition to drive osteoclastogenesis and bone loss. In vitro-derived ET2 osteoclasts are more spread and more numerous with increases in RANK, triggering receptor expressed on myeloid cells 2 (TREM2), and nuclear factor of activated T cells, cytoplasmic 1 (NFATc1) compared to wild type. However, their resorptive capacity does not increase accordingly. Thus, E proteins participate in osteoclast maturation and survival in homeostatic bone remodeling.
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Affiliation(s)
- Courtney L. Long
- Microbiology and Immunology, Graduate College, University of Oklahoma Health Science Center, Oklahoma City, OK
| | - William L. Berry
- Department of Cell Biology, University of Oklahoma Health Science Center, Oklahoma City, OK
| | - Ying Zhao
- Immunobiology and Cancer, Oklahoma Medical Research Foundation, Oklahoma City, OK
| | - Xiao-Hong Sun
- Immunobiology and Cancer, Oklahoma Medical Research Foundation, Oklahoma City, OK
| | - Mary Beth Humphrey
- Microbiology and Immunology, Graduate College, University of Oklahoma Health Science Center, Oklahoma City, OK
- Medicine, University of Oklahoma Health Science Center, Oklahoma City, OK
- Veteran Affairs Medical Center, Oklahoma City, OK
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15
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San-Marina S, Han Y, Liu J, Minden MD. Suspected leukemia oncoproteins CREB1 and LYL1 regulate Op18/STMN1 expression. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2012; 1819:1164-72. [PMID: 23000483 DOI: 10.1016/j.bbagrm.2012.09.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2012] [Revised: 09/04/2012] [Accepted: 09/07/2012] [Indexed: 12/27/2022]
Abstract
Stathmin (STMN1) is a microtubule destabilizing protein with a key role in cell cycle progression and cell migration that is up-regulated in several cancers and may contribute to the malignant phenotype. However, the factors that regulate its expression are not well understood. Loss as well as gain-of-function p53 mutations up-regulate STMN1 and in acute myelogenous leukemia where p53 is predominantly wild-type, STMN1 is also over-expressed. Here we show regulatory control of STMN1 expression by the leucine zipper transcription factor (TF) CREB1 and the basic helix-loop-helix TF LYL1. By ChIP-chip experiments we demonstrate in vivo the presence of LYL1 and CREB1 in close proximity on the STMN1 promoter and using promoter assays we reveal co-regulation of STMN1 by CREB1 and LYL1. By contrast, TAL1, another suspected oncoprotein in leukemia and close relative of LYL1, exerts no regulatory effect on the STMN1 promoter. NLI, LMO2 and GATA2 are previously described co-activators of Tal1/Lyl1-E47 transcriptional complexes and potentiate Lyl1 activation of the STMN1 promoter while having no effect on TAL1 transactivation. Promoter mutations that abrogate CREB1 proximal binding or mutations of the DNA-binding domain of CREB1 abolish LYL1 transcriptional activation. These results show that CRE and Ebox sites function as coordinated units and support previous evidence of joint CREB1-and LYL1 transcription events activating an aberrant subset of promoters in leukemia. CREB1 or LYL1 shRNA knock-down down-regulate STMN1 expression. Because down-regulation of STMN1 has been shown to have anti-proliferative effects, while CREB1 and LYL1 are suspected oncoproteins, interference with CREB1-LYL1 interactions may complement standard chemotherapy and yield additional beneficial effects.
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Affiliation(s)
- Serban San-Marina
- University Health Network, Princess Margaret Hospital, Toronto ON, Canada.
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16
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Increased expression of bHLH transcription factor E2A (TCF3) in prostate cancer promotes proliferation and confers resistance to doxorubicin induced apoptosis. Biochem Biophys Res Commun 2012; 422:146-51. [PMID: 22564737 DOI: 10.1016/j.bbrc.2012.04.126] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2012] [Accepted: 04/21/2012] [Indexed: 11/20/2022]
Abstract
E2A (TCF3) is a multifunctional basic helix loop helix (bHLH), transcription factor. E2A regulates transcription of target genes by homo- or heterodimerization with cell specific bHLH proteins. In general, E2A promotes cell differentiation, acts as a negative regulator of cell proliferation in normal cells and cancer cell lines and is required for normal B-cell development. Given the diverse biological pathways regulated/influenced by E2A little is known about its expression in cancer. In this study we investigated the expression of E2A in prostate cancer. Unexpectedly, E2A immuno-histochemistry demonstrated increased E2A expression in prostate cancer as compared to normal prostate. Silencing of E2A in prostate cancer cells DU145 and PC3 led to a significant reduction in proliferation due to G1 arrest that was in part mediated by increased CDKN1A(p21) and decreased Id1, Id3 and c-myc. E2A silencing in prostate cancer cell lines also resulted in increased apoptosis due to increased mitochondrial permeability and caspase 3/7 activation. Moreover, silencing of E2A increased sensitivity to doxorubicin induced apoptosis. Based on our results, we propose that E2A could be an upstream regulator of Id1 and c-Myc which are highly expressed in prostate cancer. These results for the first time demonstrate that E2A could in fact acts as a tumor promoter at least in prostate cancer.
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17
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Wang HC, Peng V, Zhao Y, Sun XH. Enhanced Notch activation is advantageous but not essential for T cell lymphomagenesis in Id1 transgenic mice. PLoS One 2012; 7:e32944. [PMID: 22393458 PMCID: PMC3290631 DOI: 10.1371/journal.pone.0032944] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2011] [Accepted: 02/02/2012] [Indexed: 01/06/2023] Open
Abstract
T cell lymphoblastic leukemia (T-ALL) is known to be associated with chromosomal abnormalities that lead to aberrant expression of a number of transcription factors such as TAL1, which dimerizes with basic helix-loop-helix (bHLH) E proteins and inhibits their function. Activated Notch receptors also efficiently induce T cell leukemogenesis in mouse models. Interestingly, gain-of-function mutations or cryptic transcription initiation of the Notch1 gene have been frequently found in both human and mouse T-ALL. However, the correlations between these alterations and overall Notch activities or leukemogenesis have not been thoroughly evaluated. Therefore, we made use of our collection of T cell lymphomas developed in transgenic mice expressing Id1, which like TAL1, inhibits E protein function. By comparing expression levels of Notch target genes in Id1-expressing tumors to those in tumors induced by a constitutively active form of Notch1, N1C, we were able to assess the overall activities of Notch pathways and conclude that the majority of Id1-expressing tumors had elevated Notch function to a varying degree. However, 26% of the Id1-expressing tumors had no evidence of enhanced Notch activation, but that did not delay the onset of tumorigenesis. Furthermore, we examined the genetic or epigenetic alterations thought to contribute to ligand-independent activation or protein stabilization of Notch1 and found that some of the Id1-expressing tumors acquired these changes, but they are not uniformly associated with elevated Notch activities in Id1 tumor samples. In contrast, N1C-expressing tumors do not harbor any PEST domain mutations nor exhibit intragenic transcription initiation. Taken together, it appears that Notch activation provides Id1-expressing tumor cells with selective advantages in growth and survival. However, this may not be absolutely essential for lymphomagenesis in Id1 transgenic mice and additional factors could also cooperate with Id1 to induce T cell lymphoma. Therefore, a broad approach is necessary in designing T-ALL therapy.
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Affiliation(s)
- Hong-Cheng Wang
- Immunobiology and Cancer Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, United States of America
| | - Vincent Peng
- Oklahoma School of Science and Mathematics, Oklahoma City, Oklahoma, United States of America
| | - Ying Zhao
- Immunobiology and Cancer Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, United States of America
| | - Xiao-Hong Sun
- Immunobiology and Cancer Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, United States of America
- * E-mail:
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18
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Kusy S, Gerby B, Goardon N, Gault N, Ferri F, Gérard D, Armstrong F, Ballerini P, Cayuela JM, Baruchel A, Pflumio F, Roméo PH. NKX3.1 is a direct TAL1 target gene that mediates proliferation of TAL1-expressing human T cell acute lymphoblastic leukemia. ACTA ACUST UNITED AC 2010; 207:2141-56. [PMID: 20855495 PMCID: PMC2947082 DOI: 10.1084/jem.20100745] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
TAL1 (also known as SCL) is expressed in >40% of human T cell acute lymphoblastic leukemias (T-ALLs). TAL1 encodes a basic helix-loop-helix transcription factor that can interfere with the transcriptional activity of E2A and HEB during T cell leukemogenesis; however, the oncogenic pathways directly activated by TAL1 are not characterized. In this study, we show that, in human TAL1–expressing T-ALL cell lines, TAL1 directly activates NKX3.1, a tumor suppressor gene required for prostate stem cell maintenance. In human T-ALL cell lines, NKX3.1 gene activation is mediated by a TAL1–LMO–Ldb1 complex that is recruited by GATA-3 bound to an NKX3.1 gene promoter regulatory sequence. TAL1-induced NKX3.1 activation is associated with suppression of HP1-α (heterochromatin protein 1 α) binding and opening of chromatin on the NKX3.1 gene promoter. NKX3.1 is necessary for T-ALL proliferation, can partially restore proliferation in TAL1 knockdown cells, and directly regulates miR-17-92. In primary human TAL1-expressing leukemic cells, the NKX3.1 gene is expressed independently of the Notch pathway, and its inactivation impairs proliferation. Finally, TAL1 or NKX3.1 knockdown abrogates the ability of human T-ALL cells to efficiently induce leukemia development in mice. These results suggest that tumor suppressor or oncogenic activity of NKX3.1 depends on tissue expression.
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Affiliation(s)
- Sophie Kusy
- Laboratoire de recherche sur la Réparation et la Transcription dans les cellules Souches, Direction des Sciences du Vivant, Commissariat à l'Energie Atomique et aux Energies Alternatives, 92265 Fontenay-aux-Roses, France
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19
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The TAL1/SCL transcription factor regulates cell cycle progression and proliferation in differentiating murine bone marrow monocyte precursors. Mol Cell Biol 2010; 30:2181-92. [PMID: 20194619 DOI: 10.1128/mcb.01441-09] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Monocytopoiesis involves the stepwise differentiation in the bone marrow (BM) of common myeloid precursors (CMPs) to monocytes. The basic helix-loop-helix transcription factor TAL1/SCL plays a critical role in other hematopoietic lineages, and while it had been reported to be expressed by BM-derived macrophages, its role in monocytopoiesis had not been elucidated. Using cell explant models of monocyte/macrophage (MM) differentiation, one originating with CMPs and the other from more committed precursors, we characterized the phenotypic and molecular consequences of inactivation of Tal1 expression ex vivo. While Tal1 knockout had minimal effects on cell survival and slightly accelerated terminal differentiation, it profoundly inhibited cell proliferation and decreased entry into and traversal of the G(1) and S phases. In conjunction, steady-state levels of p16(Ink4a) mRNA were increased and those of Gata2 mRNA decreased. Chromatin immunoprecipitation analysis demonstrated the association of Tal1 and E47, one of its E protein DNA-binding partners, with an E box-GATA sequence element in intron 4 of the Gata2 gene and with three E boxes upstream of p16(Ink4a). Finally, wild-type Tal1, but not a DNA binding-defective mutant, rescued the proliferative defect in Tal1-null MM precursors. These results document the importance of this transcription factor in cell cycle progression and proliferation during monocytopoiesis and the requirement for direct DNA binding in these processes.
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20
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Lausen J, Pless O, Leonard F, Kuvardina ON, Koch B, Leutz A. Targets of the Tal1 transcription factor in erythrocytes: E2 ubiquitin conjugase regulation by Tal1. J Biol Chem 2009; 285:5338-46. [PMID: 20028976 DOI: 10.1074/jbc.m109.030296] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The Tal1 transcription factor is essential for the development of the hematopoietic system and plays a role during definitive erythropoiesis in the adult. Despite the importance of Tal1 in erythropoiesis, only a small number of erythroid differentiation target genes are known. A chromatin precipitation and cloning approach was established to uncover novel Tal1 target genes in erythropoiesis. The BirA tag/BirA ligase biotinylation system in combination with streptavidin chromatin precipitation (Strep-CP) was used to co-precipitate genomic DNA bound to Tal1. Tal1 was found to bind in the vicinity of 31 genes including the E2-ubiquitin conjugase UBE2H gene. Binding of Tal1 to UBE2H was confirmed by chromatin immunoprecipitation. UBE2H expression is increased during erythroid differentiation of hCD34(+) cells. Tal1 expression activated UBE2H expression, whereas Tal1 knock-down reduced UBE2H expression and ubiquitin transfer activity. This study identifies parts of the ubiquitinylation machinery as a cellular target downstream of the transcription factor Tal1 and provides novel insights into Tal1-regulated erythropoiesis.
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Affiliation(s)
- Jörn Lausen
- Georg-Speyer-Haus, Institute for Biomedical Research, D-60596 Frankfurt (Main), Germany.
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21
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Cheng C, Li LM, Alves P, Gerstein M. Systematic identification of transcription factors associated with patient survival in cancers. BMC Genomics 2009; 10:225. [PMID: 19442316 PMCID: PMC2686740 DOI: 10.1186/1471-2164-10-225] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2008] [Accepted: 05/15/2009] [Indexed: 12/23/2022] Open
Abstract
Background Aberrant activation or expression of transcription factors has been implicated in the tumorigenesis of various types of cancer. In spite of the prevalent application of microarray experiments for profiling gene expression in cancer samples, they provide limited information regarding the activities of transcription factors. However, the association between transcription factors and cancers is largely dependent on the transcription regulatory activities rather than mRNA expression levels. Results In this paper, we propose a computational approach that integrates microarray expression data with the transcription factor binding site information to systematically identify transcription factors associated with patient survival given a specific cancer type. This approach was applied to two gene expression data sets for breast cancer and acute myeloid leukemia. We found that two transcription factor families, the steroid nuclear receptor family and the ATF/CREB family, are significantly correlated with the survival of patients with breast cancer; and that a transcription factor named T-cell acute lymphocytic leukemia 1 is significantly correlated with acute myeloid leukemia patient survival. Conclusion Our analysis identifies transcription factors associating with patient survival and provides insight into the regulatory mechanism underlying the breast cancer and leukemia. The transcription factors identified by our method are biologically meaningful and consistent with prior knowledge. As an insightful tool, this approach can also be applied to other microarray cancer data sets to help researchers better understand the intricate relationship between transcription factors and diseases.
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Affiliation(s)
- Chao Cheng
- Program in Computational Biology and Bioinformatics, Yale University, New Haven, CT, USA.
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22
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Abstract
Hematopoiesis consists of a series of lineage decisions controlled by specific gene expression that is regulated by transcription factors and intracellular signaling events in response to environmental cues. Here, we demonstrate that the balance between E-protein transcription factors and their inhibitors, Id proteins, is important for the myeloid-versus-lymphoid fate choice. Using Id1-GFP knockin mice, we show that transcription of the Id1 gene begins to be up-regulated at the granulocyte-macrophage progenitor stage and continues throughout myelopoiesis. Id1 expression is also stimulated by cytokines favoring myeloid differentiation. Forced expression of Id1 in multipotent progenitors promotes myeloid development and suppresses B-cell formation. Conversely, enhancing E-protein activity by expressing a variant of E47 resistant to Id-mediated inhibition prevents the myeloid cell fate while driving B-cell differentiation from lymphoid-primed multipotent progenitors. Together, these results suggest a crucial function for E proteins in the myeloid-versus-lymphoid lineage decision.
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Abstract
T-cell acute lymphoblastic leukaemia (T-ALL) is induced by the transformation of T-cell progenitors and mainly occurs in children and adolescents. Although treatment outcome in patients with T-ALL has improved in recent years, patients with relapsed disease continue to have a poor prognosis. It is therefore important to understand the molecular pathways that control both the induction of transformation and the treatment of relapsed disease. In this Review, we focus on the molecular mechanisms responsible for disease induction and maintenance. We also compare the physiological progression of T-cell differentiation with T-cell transformation, highlighting the close relationship between these two processes. Finally, we discuss potential new therapies that target oncogenic pathways in T-ALL.
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Nie L, Wu H, Sun XH. Ubiquitination and Degradation of Tal1/SCL Are Induced by Notch Signaling and Depend on Skp2 and CHIP. J Biol Chem 2008; 283:684-92. [DOI: 10.1074/jbc.m704981200] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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25
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San-Marina S, Han Y, Suarez Saiz F, Trus MR, Minden MD. Lyl1 interacts with CREB1 and alters expression of CREB1 target genes. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2007; 1783:503-17. [PMID: 18160048 DOI: 10.1016/j.bbamcr.2007.11.015] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2007] [Revised: 11/19/2007] [Accepted: 11/20/2007] [Indexed: 11/26/2022]
Abstract
The basic helix-loop-helix (bHLH) transcription factor family contains key regulators of cellular proliferation and differentiation as well as the suspected oncoproteins Tal1 and Lyl1. Tal1 and Lyl1 are aberrantly over-expressed in leukemia as a result of chromosomal translocations, or other genetic or epigenetic events. Protein-protein and protein-DNA interactions described so far are mediated by their highly homologous bHLH domains, while little is known about the function of other protein domains. Hetero-dimers of Tal1 and Lyl1 with E2A or HEB, decrease the rate of E2A or HEB homo-dimer formation and are poor activators of transcription. In vitro, these hetero-dimers also recognize different binding sites from homo-dimer complexes, which may also lead to inappropriate activation or repression of promoters in vivo. Both mechanisms are thought to contribute to the oncogenic potential of Tal1 and Lyl1. Despite their bHLH structural similarity, accumulating evidence suggests that Tal1 and Lyl1 target different genes. This raises the possibility that domains flanking the bHLH region, which are distinct in the two proteins, may participate in target recognition. Here we report that CREB1, a widely-expressed transcription factor and a suspected oncogene in acute myelogenous leukemia (AML) was identified as a binding partner for Lyl1 but not for Tal1. The interaction between Lyl1 and CREB1 involves the N terminal domain of Lyl1 and the Q2 and KID domains of CREB1. The histone acetyl-transferases p300 and CBP are recruited to these complexes in the absence of CREB1 Ser 133 phosphorylation. In the Id1 promoter, Lyl1 complexes direct transcriptional activation. We also found that in addition to Id1, over-expressed Lyl1 can activate other CREB1 target promoters such as Id3, cyclin D3, Brca1, Btg2 and Egr1. Moreover, approximately 50% of all gene promoters identified by ChIP-chip experiments were jointly occupied by CREB1 and Lyl1, further strengthening the association of Lyl1 with Cre binding sites. Given the newly recognized importance of CREB1 in AML, the ability of Lyl1 to modulate promoter responses to CREB1 suggests that it plays a role in the malignant phenotype by occupying different promoters than Tal1.
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Affiliation(s)
- Serban San-Marina
- Ontario Cancer Institute/Princess Margaret Hospital, 610 University Avenue 9-111, Toronto, Ontario, Canada M5G 2M9
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26
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Perry SS, Zhao Y, Nie L, Cochrane SW, Huang Z, Sun XH. Id1, but not Id3, directs long-term repopulating hematopoietic stem-cell maintenance. Blood 2007; 110:2351-60. [PMID: 17622570 PMCID: PMC1988946 DOI: 10.1182/blood-2007-01-069914] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
E-proteins are widely expressed basic helix-loop-helix (HLH) transcription factors that regulate differentiation in many cell lineages, including lymphoid, muscle, and neuronal cells. E-protein function is controlled by HLH inhibitors such as Id and SCL/TAL1 proteins, which recently have been suggested to play a role in hematopoietic stem cell (HSC) differentiation. However, the precise stages when these proteins are expressed and their specific functions are not entirely clear. Using a knock-in mouse model where the sequence for the enhanced green fluorescent protein (GFP) was inserted downstream of the Id1 promoter, we were able to track Id1 expression on an individual cell basis and detected Id1 expression in long-term repopulating HSCs (LT-HSCs). Functional assays showed that the Id1/GFP(+)Lin(-)Sca1(+)c-kit(Hi) population was highly enriched for LT-HSCs. Consistent with this expression pattern, Id1 deficiency led to a 2-fold reduction in the number of LT-HSCs defined as Lin(-)Sca1(+)c-kit(Hi)CD48(-)CD150(+). Primary bone marrow transplantation studies revealed that Id1 is dispensable for short-term engraftment. In contrast, both Id1(-/-) whole bone marrow and Lin(-)Sca1(+)c-kit(Hi)Thy1.1(Lo)-enriched HSCs, but not Id3(-/-) marrow, displayed impaired engraftment relative to wild-type controls in secondary transplantation assays. These findings suggest a unique role for Id1 in LT-HSC maintenance and hematopoietic development.
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Affiliation(s)
- S Scott Perry
- Immunobiology and Cancer Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA
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27
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Palomero T, Odom DT, O'Neil J, Ferrando AA, Margolin A, Neuberg DS, Winter SS, Larson RS, Li W, Liu XS, Young RA, Look AT. Transcriptional regulatory networks downstream of TAL1/SCL in T-cell acute lymphoblastic leukemia. Blood 2006; 108:986-92. [PMID: 16621969 PMCID: PMC1895859 DOI: 10.1182/blood-2005-08-3482] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Aberrant expression of 1 or more transcription factor oncogenes is a critical component of the molecular pathogenesis of human T-cell acute lymphoblastic leukemia (T-ALL); however, oncogenic transcriptional programs downstream of T-ALL oncogenes are mostly unknown. TAL1/SCL is a basic helix-loop-helix (bHLH) transcription factor oncogene aberrantly expressed in 60% of human T-ALLs. We used chromatin immunoprecipitation (ChIP) on chip to identify 71 direct transcriptional targets of TAL1/SCL. Promoters occupied by TAL1 were also frequently bound by the class I bHLH proteins E2A and HEB, suggesting that TAL1/E2A as well as TAL1/HEB heterodimers play a role in transformation of T-cell precursors. Using RNA interference, we demonstrated that TAL1 is required for the maintenance of the leukemic phenotype in Jurkat cells and showed that TAL1 binding can be associated with either repression or activation of genes whose promoters occupied by TAL1, E2A, and HEB. In addition, oligonucleotide microarray analysis of RNA from 47 primary T-ALL samples showed specific expression signatures involving TAL1 targets in TAL1-expressing compared with -nonexpressing human T-ALLs. Our results indicate that TAL1 may act as a bifunctional transcriptional regulator (activator and repressor) at the top of a complex regulatory network that disrupts normal T-cell homeostasis and contributes to leukemogenesis.
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Affiliation(s)
- Teresa Palomero
- Institute for Cancer Genetics, Columbia University, 1150 St Nicholas Ave, New York, NY 10032, USA
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28
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Schuh AH, Tipping AJ, Clark AJ, Hamlett I, Guyot B, Iborra FJ, Rodriguez P, Strouboulis J, Enver T, Vyas P, Porcher C. ETO-2 associates with SCL in erythroid cells and megakaryocytes and provides repressor functions in erythropoiesis. Mol Cell Biol 2005; 25:10235-50. [PMID: 16287841 PMCID: PMC1291220 DOI: 10.1128/mcb.25.23.10235-10250.2005] [Citation(s) in RCA: 115] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2005] [Revised: 05/07/2005] [Accepted: 09/14/2005] [Indexed: 12/19/2022] Open
Abstract
Lineage specification and cellular maturation require coordinated regulation of gene expression programs. In large part, this is dependent on the activator and repressor functions of protein complexes associated with tissue-specific transcriptional regulators. In this study, we have used a proteomic approach to characterize multiprotein complexes containing the key hematopoietic regulator SCL in erythroid and megakaryocytic cell lines. One of the novel SCL-interacting proteins identified in both cell types is the transcriptional corepressor ETO-2. Interaction between endogenous proteins was confirmed in primary cells. We then showed that SCL complexes are shared but also significantly differ in the two cell types. Importantly, SCL/ETO-2 interacts with another corepressor, Gfi-1b, in red cells but not megakaryocytes. The SCL/ETO-2/Gfi-1b association is lost during erythroid differentiation of primary fetal liver cells. Genetic studies of erythroid cells show that ETO-2 exerts a repressor effect on SCL target genes. We suggest that, through its association with SCL, ETO-2 represses gene expression in the early stages of erythroid differentiation and that alleviation/modulation of the repressive state is then required for expression of genes necessary for terminal erythroid maturation to proceed.
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Affiliation(s)
- Anna H Schuh
- MRC Molecular Haematology Unit, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, Oxford OX3 9DS, United Kingdom
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29
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Hong CY, Gong EY, Kim K, Suh JH, Ko HM, Lee HJ, Choi HS, Lee K. Modulation of the expression and transactivation of androgen receptor by the basic helix-loop-helix transcription factor Pod-1 through recruitment of histone deacetylase 1. Mol Endocrinol 2005; 19:2245-57. [PMID: 15919722 DOI: 10.1210/me.2004-0400] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Androgen receptor (AR) is important in male sexual differentiation and testicular function. Here, we demonstrate the regulation of AR expression and its transactivation by the basic helix-loop-helix (bHLH) transcription factor Pod-1, the expression of which in postnatal testis reciprocally coincides with the expression of AR. Pod-1 represses the promoter activity of AR, possibly through its E-box. An AR promoter region of 169 bp, which harbors one canonical E-box, is sufficient for the Pod-1-repression and bound by purified Pod-1 proteins. Pod-1 also suppresses the transactivation of AR. Transient transfection analyses of mammalian cells show that Pod-1 represses AR transactivation in a dose-dependent manner. Furthermore, yeast two-hybrid, glutathione-S-transferase-pull-down, and co-immunoprecipitation analyses reveal that Pod-1 directly associates with AR through its N-terminal region and through the DNA binding-hinge domain of AR. Interestingly, Pod-1 recruits histone deacetylase (HDAC)-1 to inhibit both promoter activity and transactivation of AR. Overexpression of HDAC1 further inhibits the Pod-1-mediated repressions and Pod-1 directly interacts with HDAC1. Furthermore, chromatin immunoprecipitation assay reveals that HDAC1 is recruited with Pod-1 to the endogenous AR promoter and the androgen-regulated Pem promoter. Taken together, these results suggest that Pod-1, which controls AR transcription and function, may play an important role in the development and function of the testis.
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Affiliation(s)
- Cheol Yi Hong
- Hormone Research Center, School of Biological Sciences and Research, Chonnam National University, Gwangju 500-757, Republic of Korea
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Zweidler-McKay PA, He Y, Xu L, Rodriguez CG, Karnell FG, Carpenter AC, Aster JC, Allman D, Pear WS. Notch signaling is a potent inducer of growth arrest and apoptosis in a wide range of B-cell malignancies. Blood 2005; 106:3898-906. [PMID: 16118316 PMCID: PMC1895093 DOI: 10.1182/blood-2005-01-0355] [Citation(s) in RCA: 152] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Although Notch receptor expression on malignant B cells is widespread, the effect of Notch signaling in these cells is poorly understood. To investigate Notch signaling in B-cell malignancy, we assayed the effect of Notch activation in multiple murine and human B-cell tumors, representing both immature and mature subtypes. Expression of constitutively active, truncated forms of the 4 mammalian Notch receptors (ICN1-4) inhibited growth and induced apoptosis in both murine and human B-cell lines but not T-cell lines. Similar results were obtained in human precursor B-cell acute lymphoblastic leukemia lines when Notch activation was achieved by coculture with fibroblasts expressing the Notch ligands Jagged1 or Jagged2. All 4 truncated Notch receptors, as well as the Jagged ligands, induced Hes1 transcription. Retroviral expression of Hairy/Enhancer of Split-1 (Hes1) recapitulated the Notch effects, suggesting that Hes1 is an important mediator of Notch-induced growth arrest and apoptosis in B cells. Among the B-cell malignancies that were susceptible to Notch-mediated growth inhibition/apoptosis were mature B-cell and therapy-resistant B-cell malignancies, including Hodgkin, myeloma, and mixed-lineage leukemia (MLL)-translocated cell lines. These results suggest that therapies capable of activating Notch/Hes1 signaling may have therapeutic potential in a wide range of human B-cell malignancies.
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Affiliation(s)
- Patrick A Zweidler-McKay
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, 611 BRB II/III, 421 Curie Blvd, Philadelphia, PA 19104-6160, USA
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31
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Huang Z, Nie L, Xu M, Sun XH. Notch-induced E2A degradation requires CHIP and Hsc70 as novel facilitators of ubiquitination. Mol Cell Biol 2004; 24:8951-62. [PMID: 15456869 PMCID: PMC517891 DOI: 10.1128/mcb.24.20.8951-8962.2004] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
E2A transcription factors, E12 and E47, are important regulators of lymphocyte development. Notch signaling pathways have been shown to regulate E2A function by accelerating the degradation of E2A proteins through a mitogen-activated protein kinase-dependent and ubiquitin-mediated pathway. To further understand the mechanism underlying E2A ubiquitination and degradation, we conducted a yeast two-hybrid screen and identified the carboxyl terminus of Hsc70-interacting protein (CHIP) as an E47 binding protein. Here, we show that CHIP associates with E2A proteins in vivo and that overexpression of CHIP induces E47 degradation in a phosphorylation-dependent manner. Conversely, knocking down CHIP with small interfering RNA alleviates Notch-induced E47 degradation. CHIP binds E47 through the E protein homology domains 2 and 3 (EHD2 and EHD3). This interaction between CHIP and E47 is independent of the U-box domain with E3 ubiquitin ligase activity but requires the chaperone binding tetratricopeptide repeats domain. The ability of CHIP to induce E47 ubiquitination and degradation correlates with its ability to bind E47. We propose that CHIP, together with its partner Hsc70, forms a preubiquitination complex (PUC) with E47 and Skp2, thus facilitating the interaction between E47 and Skp2. CHIP also associates with Cul1, which introduces PUC to the SCF E3 ligase complex, responsible for E47 ubiquitination. Therefore, CHIP plays a crucial role in the ubiquitination and degradation of E2A proteins.
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Affiliation(s)
- Zhong Huang
- Immunobiology and Cancer Program, Oklahoma Medical Research Foundation, 825 NE 13th St., Oklahoma City, OK 73104, USA
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32
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Schlaeger TM, Schuh A, Flitter S, Fisher A, Mikkola H, Orkin SH, Vyas P, Porcher C. Decoding hematopoietic specificity in the helix-loop-helix domain of the transcription factor SCL/Tal-1. Mol Cell Biol 2004; 24:7491-502. [PMID: 15314159 PMCID: PMC506978 DOI: 10.1128/mcb.24.17.7491-7502.2004] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The helix-loop-helix (HLH) domain is employed by many transcription factors that control cell fate choice in multiple developmental settings. Previously, we demonstrated that the HLH domain of the class II basic HLH (bHLH) protein SCL/Tal-1 is critical for hematopoietic specification. We have now identified residues in this domain that are essential for restoring hematopoietic development to SCL-/- embryonic stem cells and sufficient to convert a muscle-specific HLH domain to one able to rescue hematopoiesis. Most of these critical residues are distributed in the loop of SCL, with one in helix 2. This is in contrast to the case for MyoD, the prototype of class II bHLH proteins, where the loop seems to serve mainly as a linker between the two helices. Among the identified residues, some promote heterodimerization with the bHLH partners of SCL (E12/E47), while others, unimportant for this property, are still crucial for the biological function of SCL. Importantly, the residue in helix 2 specifically promotes interaction with a known partner of SCL, the LIM-only protein LMO2, a finding that strengthens genetic evidence that these proteins interact. Our data highlight the functional complexity of bHLH proteins, provide mechanistic insight into SCL function, and strongly support the existence of an active SCL/LMO2-containing multiprotein complex in early hematopoietic cells.
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Affiliation(s)
- Thorsten M Schlaeger
- Department of Hematology/Oncology, Children's Hospital and Dana Farber Cancer Institute, Howard Hughes Medical Institute, Harvard Medical School, Boston, MA, USA
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33
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Hansson A, Manetopoulos C, Jönsson JI, Axelson H. The basic helix-loop-helix transcription factor TAL1/SCL inhibits the expression of the p16INK4A and pTalpha genes. Biochem Biophys Res Commun 2004; 312:1073-81. [PMID: 14651981 DOI: 10.1016/j.bbrc.2003.11.030] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The Tal1 gene (also called Scl or TCL5) encodes a basic helix-loop-helix transcription factor required for hematopoiesis and vasculogenesis. Additionally, aberrant transcriptional activation of the Tal1 gene is a frequent event in human T cell acute lymphoblastic leukemia (T-ALL). T cell specific expression of TAL1 in mice induces aggressive T cell malignancies, demonstrating the oncogenic potential of TAL1. Yet, the underlying mechanisms of TAL1 induced tumorigenesis are poorly understood. By inhibiting E protein mediated transcription of the pTalpha gene, TAL1 can interfere with the T cell differentiation program. In addition, several studies suggest that TAL1 expression might also enhance proliferation rate. We report here that TAL1 can bind the E boxes in both the p16 and the pTalpha promoters, and functionally suppress the activity of both promoters. These results indicate that TAL1 can affect both T cell proliferation and differentiation. Moreover, we show that overexpression of TAL1 in hematopoietic progenitor cells promotes cell cycle division.
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Affiliation(s)
- Anders Hansson
- Department of Laboratory Medicine, Division of Molecular Medicine, Lund University, University Hospital MAS, SE-205 02, Malmö, Sweden
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34
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Abstract
In the hematopoietic system, lineage commitment and differentiation is controlled by the combinatorial action of transcription factors from diverse families. SCL is a basic helix-loop-helix transcription factor that is an essential regulator at several levels in the hematopoietic hierarchy and whose inappropriate regulation frequently contributes to the development of pediatric T-cell acute lymphoblastic leukemia. This review discusses advances that have shed important light on the functions played by SCL during normal hematopoiesis and leukemogenesis and have revealed an unexpected robustness of hematopoietic stem cell function. Molecular studies have unraveled a mechanism through which gene expression is tightly controlled, as SCL functions within multifactorial complexes that exhibit an all-or-none switch-like behavior in transcription activation, arguing for a quantal process that depends on the concurrent occupation of target loci by all members of the complex. Finally, variations in composition of SCL-containing complexes may ensure flexibility and specificity in the regulation of lineage-specific programs of gene expression, thus providing the molecular basis through which SCL exerts its essential functions at several branch points of the hematopoietic hierarchy.
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Affiliation(s)
- Eric Lécuyer
- Institut de Recherche en Immunovirologie et Cancérologie (IRIC), Montreal, Quebec, Canada
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35
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Affiliation(s)
- Xiao-Hong Sun
- Immunobiology and Cancer Program, Oklahoma Medical Research Foundation Oklahoma City, OK 73104, USA
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36
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Nie L, Xu M, Vladimirova A, Sun XH. Notch-induced E2A ubiquitination and degradation are controlled by MAP kinase activities. EMBO J 2003; 22:5780-92. [PMID: 14592976 PMCID: PMC275424 DOI: 10.1093/emboj/cdg567] [Citation(s) in RCA: 147] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Notch signals are important for lymphocyte development but downstream events that follow Notch signaling are not well understood. Here, we report that signaling through Notch modulates the turnover of E2A proteins including E12 and E47, which are basic helix-loop-helix proteins crucial for B and T lymphocyte development. Notch-induced degradation requires phosphorylation of E47 by p42/p44 MAP kinases. Expression of the intracellular domain of Notch1 (N1-IC) enhances the association of E47 with the SCF(Skp2) E3 ubiquitin ligase and ubiquitination of E47, followed by proteasome-mediated degradation. Furthermore, N1-IC induces E2A degradation in B and T cells in the presence of activated MAP kinases. Activation of endogenous Notch receptors by treatment of splenocytes with anti-IgM or anti-CD3 plus anti-CD28 also leads to E2A degradation, which is blocked by the inhibitors of Notch activation or proteasome function. Notch-induced E2A degradation depends on the function of its downstream effector, RBP-Jkappa, probably to activate target genes involved in the ubiquitination of E2A proteins. Thus we propose that Notch regulates lymphocyte differentiation by controlling E2A protein turnover.
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Affiliation(s)
- Lei Nie
- Immunobiology and Cancer Program, Oklahoma Medical Research Foundation, 825 NE 13th Street, Oklahoma City, OK 73104, USA
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37
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Tremblay M, Herblot S, Lecuyer E, Hoang T. Regulation of pT alpha gene expression by a dosage of E2A, HEB, and SCL. J Biol Chem 2003; 278:12680-7. [PMID: 12566462 DOI: 10.1074/jbc.m209870200] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The expression of the pT alpha gene is required for effective selection, proliferation, and survival of beta T-cell receptor (beta TCR)-expressing immature thymocytes. Here, we have identified two phylogenetically conserved E-boxes within the pT alpha enhancer sequence that are required for optimal enhancer activity and for its stage-specific activity in immature T cells. We have shown that the transcription factors E2A and HEB associate with high affinity to these E-boxes. Moreover, we have identified pT alpha as a direct target of E2A-HEB heterodimers in immature thymocytes because they specifically occupy the enhancer in vivo. In these cells, pT alpha mRNA levels are determined by the presence of one or two functional E2A or HEB alleles. Furthermore, E2A/HEB transcriptional activity is repressed by heterodimerization with SCL, a transcription factor that is turned off in differentiating thymocytes exactly at a stage when pT alpha is up-regulated. Taken together, our observations suggest that the dosage of E2A, HEB, and SCL determines pT alpha gene expression in immature T cells.
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MESH Headings
- Amino Acid Sequence
- Animals
- Animals, Newborn
- Basic Helix-Loop-Helix Transcription Factors
- Cell Line
- Consensus Sequence
- DNA-Binding Proteins/deficiency
- DNA-Binding Proteins/genetics
- Enhancer Elements, Genetic
- Flow Cytometry
- Helix-Loop-Helix Motifs
- Humans
- Membrane Glycoproteins/genetics
- Mice
- Mice, Knockout
- Molecular Sequence Data
- Promoter Regions, Genetic
- Proto-Oncogene Proteins/deficiency
- Proto-Oncogene Proteins/genetics
- RNA, Messenger/genetics
- Receptors, Antigen, T-Cell, alpha-beta/genetics
- Sequence Homology, Amino Acid
- T-Cell Acute Lymphocytic Leukemia Protein 1
- T-Lymphocytes/immunology
- Thymus Gland/immunology
- Transcription Factors/deficiency
- Transcription Factors/genetics
- Transcription, Genetic
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Affiliation(s)
- Mathieu Tremblay
- Clinical Research Institute of Montréal, Montréal, Québec H2W 1R7, Canada
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38
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Engel I, Murre C. Disruption of pre-TCR expression accelerates lymphomagenesis in E2A-deficient mice. Proc Natl Acad Sci U S A 2002; 99:11322-7. [PMID: 12172006 PMCID: PMC123255 DOI: 10.1073/pnas.162373999] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The helix-loop-helix proteins E47 and E12, which are encoded by the E2A gene, regulate several stages of T cell development. In addition, mice deficient for E2A are highly susceptible to thymic lymphoma. Here we report that the development of lymphoma in E2A-deficient mice did not require pre- and recombinase-activating gene expression. Rather, we found that, whereas illegitimate DNA rearrangement did not play a major role in the development of these lymphomas, defects that prevented pre-T cell antigen receptor expression tended to accelerate lymphomagenesis in E2A-deficient mice. These data and previous observations also provide insight into the role of Notch in lymphoma development. Specifically, we propose that Notch activation indirectly modulates E2A activity through induction of pre-Talpha expression, ultimately leading to the development of lymphoma.
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MESH Headings
- Animals
- Basic Helix-Loop-Helix Transcription Factors
- DNA-Binding Proteins/deficiency
- DNA-Binding Proteins/genetics
- Genes, T-Cell Receptor beta
- Genotype
- Homeodomain Proteins/genetics
- Homozygote
- Lymphatic Metastasis/immunology
- Lymphoma/genetics
- Lymphoma/immunology
- Mice
- Mice, Knockout
- Receptors, Antigen, T-Cell, alpha-beta/deficiency
- Receptors, Antigen, T-Cell, alpha-beta/genetics
- Receptors, Antigen, T-Cell, alpha-beta/immunology
- Thymus Neoplasms/genetics
- Thymus Neoplasms/immunology
- Transcription Factors/deficiency
- Transcription Factors/genetics
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Affiliation(s)
- Isaac Engel
- Division of Biology, University of California at San Diego, La Jolla, CA 92093-0366, USA
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39
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Goardon N, Schuh A, Hajar I, Ma X, Jouault H, Dzierzak E, Roméo PH, Maouche-Chrétien L. Ectopic expression of TAL-1 protein in Ly-6E.1-htal-1 transgenic mice induces defects in B- and T-lymphoid differentiation. Blood 2002; 100:491-500. [PMID: 12091340 DOI: 10.1182/blood.v100.2.491] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The tal-1 gene encodes a basic helix-loop-helix (bHLH) transcription factor required for primitive and definitive hematopoiesis. Additionally, ectopic activation of the tal-1 gene during T lymphopoiesis occurs in numerous cases of human T-cell acute lymphoblastic leukemia. With the use of transgenic mice, we show that, in adult hematopoiesis, constitutive expression of TAL-1 protein causes disorders in the hematopoietic lineages that normally switch off tal-1 gene expression during their differentiation process. Myelopoiesis was characterized by a moderate increase of myeloid precursors and by Sca-1 antigen persistence. Although no lymphoid leukemia was observed, T lymphopoiesis and B lymphopoiesis were severely impaired. Transgenic mice showed reduced thymic cellularity together with a decrease in double-positive cells and a concurrent increase in the single-positive population. B cells exhibited a differentiation defect characterized by a reduction of the B-cell compartment most likely because of a differentiation block upstream of the intermediate pro-B progenitor. B cells escaping this defect developed normally, but transgenic splenocytes presented a defect in immunoglobulin class switch recombination. Altogether, these results enlighten the fine-tuning of TAL-1 expression during adult hematopoiesis and indicate why TAL-1 expression has to be switched off in the lymphoid lineages.
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Affiliation(s)
- Nicolas Goardon
- Institut Cochin, Département d'Hématologie, INSERM, CNRS, Paris, France
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40
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van der Burg M, Smit B, Brinkhof B, Barendregt BH, Verschuren MCM, Dib M, Beverloo HB, van Dongen JJM, Langerak AW. A single split-signal FISH probe set allows detection of TAL1 translocations as well as SIL-TAL1 fusion genes in a single test. Leukemia 2002; 16:755-61. [PMID: 11960364 DOI: 10.1038/sj.leu.2402432] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2001] [Accepted: 12/17/2001] [Indexed: 11/09/2022]
Abstract
About 30% of T cell acute lymphoblastic leukemias (T-ALL) carry TAL1 gene aberrations. In the majority of cases (approximately 25%), this concerns a submicroscopic deletion of approximately 90 kb in chromosome region 1p32, which deletes the coding regions of the SIL gene and the untranslated region of the TAL1 gene, thereby placing the TAL1 gene under control of the SIL promoter region. Translocation (1;14)(p32;q11) involving the TAL1 gene occurs at a much lower frequency (3%), whereas some other rare variant translocations have been described as well. In this study we developed a set of TAL1 FISH probes based on the split-signal FISH principle that enables detection of both types of TAL1 gene aberrations in single test. For this purpose, one probe was designed downstream of the TAL1 gene (TAL1-D) and the second probe in the region upstream of the TAL1 gene, partly covering the SIL gene (SIL-U). We show that this split-signal FISH probe set allows reliable detection of the unaffected SIL-TAL1 gene region with a fusion signal, SIL-TAL1 fusion genes with loss of the SIL-U signal, and TAL1 gene translocations with a split-signal, independent of the involved partner gene.
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Affiliation(s)
- M van der Burg
- Dept of Immunology, Erasmus University Rotterdam/University Hospital Rotterdam, The Netherlands
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41
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Herblot S, Aplan PD, Hoang T. Gradient of E2A activity in B-cell development. Mol Cell Biol 2002; 22:886-900. [PMID: 11784864 PMCID: PMC133542 DOI: 10.1128/mcb.22.3.886-900.2002] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2001] [Revised: 07/10/2001] [Accepted: 11/06/2001] [Indexed: 11/20/2022] Open
Abstract
The E2A locus is a frequent target of chromosomal translocations in B-cell acute lymphoblastic leukemia (B-ALL). E2A encodes two products, E12 and E47, that are part of the basic helix-loop-helix (bHLH) family of transcription factors and are central in B lineage differentiation. E2A haplo-insufficiency hinders progression through three major checkpoints in B-cell development: commitment into the B lineage, at the pro-B to pre-B transition, and in the induction of immunoglobulin M (IgM) expression required for a functional BCR. These observations underscore the importance of E2A gene dosage in B-cell development. Here we show that a higher proportion of pro-B cells in E2A(+/-) mice is in the cell cycle compared to that in wild-type littermates. This increase correlates with lower p21(waf/cip1) levels, indicating that E2A has an antiproliferative function in B-cell progenitors. Ectopic expression in the B lineage of SCL/Tal1, a tissue-specific bHLH factor that inhibits E2A function, blocks commitment into the B lineage without affecting progression through later stages of differentiation. Furthermore, ectopic SCL expression exacerbates E2A haplo-insufficiency in B-cell differentiation, indicating that SCL genetically interacts with E2A. Taken together, these observations provide evidence for a gradient of E2A activity that increases from the pre-pro-B to the pre-B stage and suggest a model in which low levels of E2A (as in pro-B cells) are sufficient to control cell growth, while high levels (in pre-B cells) are required for cell differentiation. The antiproliferative function of E2A further suggests that in B-ALL associated with t(1;19) and t(17;19), the disruption of one E2A allele contributes to leukemogenesis, in addition to other anomalies induced by E2A fusion proteins.
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Affiliation(s)
- Sabine Herblot
- The Clinical Research Institute of Montréal, Montréal, Québec, Canada
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42
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Ferrando AA, Neuberg DS, Staunton J, Loh ML, Huard C, Raimondi SC, Behm FG, Pui CH, Downing JR, Gilliland DG, Lander ES, Golub TR, Look AT. Gene expression signatures define novel oncogenic pathways in T cell acute lymphoblastic leukemia. Cancer Cell 2002; 1:75-87. [PMID: 12086890 DOI: 10.1016/s1535-6108(02)00018-1] [Citation(s) in RCA: 800] [Impact Index Per Article: 36.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Human T cell leukemias can arise from oncogenes activated by specific chromosomal translocations involving the T cell receptor genes. Here we show that five different T cell oncogenes (HOX11, TAL1, LYL1, LMO1, and LMO2) are often aberrantly expressed in the absence of chromosomal abnormalities. Using oligonucleotide microarrays, we identified several gene expression signatures that were indicative of leukemic arrest at specific stages of normal thymocyte development: LYL1+ signature (pro-T), HOX11+ (early cortical thymocyte), and TAL1+ (late cortical thymocyte). Hierarchical clustering analysis of gene expression signatures grouped samples according to their shared oncogenic pathways and identified HOX11L2 activation as a novel event in T cell leukemogenesis. These findings have clinical importance, since HOX11 activation is significantly associated with a favorable prognosis, while expression of TAL1, LYL1, or, surprisingly, HOX11L2 confers a much worse response to treatment. Our results illustrate the power of gene expression profiles to elucidate transformation pathways relevant to human leukemia.
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Affiliation(s)
- Adolfo A Ferrando
- Department of Pediatric Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA 02142, USA
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43
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Kim D, Xu M, Nie L, Peng XC, Jimi E, Voll RE, Nguyen T, Ghosh S, Sun XH. Helix-loop-helix proteins regulate pre-TCR and TCR signaling through modulation of Rel/NF-kappaB activities. Immunity 2002; 16:9-21. [PMID: 11825562 DOI: 10.1016/s1074-7613(02)00264-9] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
E2A and HEB are basic helix-loop-helix transcription factors essential for T cell development. Complete inhibition of their activities through transgenic overexpression of their inhibitors Id1 and Tal1 leads to a dramatic loss of thymocytes. Here, we suggest that bHLH proteins play important roles in establishing thresholds for pre-TCR and TCR signaling. Inhibition of their function allows double-negative cells to differentiate without a functional pre-TCR, while anti-CD3 stimulation downregulates bHLH activities. We also find that the transcription factor NF-kappaB becomes activated in transgenic thymocytes. Further activation of NF-kappaB exacerbates the loss of thymocytes, whereas inhibition of NF-kappaB leads to the rescue of double-positive thymocytes. Therefore, we propose that E2A and HEB negatively regulate pre-TCR and TCR signaling and their removal causes hyperactivation and apoptosis of thymocytes.
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Affiliation(s)
- Dongsoo Kim
- Immunobiology and Cancer Program, Oklahoma Medical Research Foundation, 825 NE 13th Street, Oklahoma City, OK 73104, USA
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44
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Yoshida S, Ohbo K, Takakura A, Takebayashi H, Okada T, Abe K, Nabeshima Y. Sgn1, a basic helix-loop-helix transcription factor delineates the salivary gland duct cell lineage in mice. Dev Biol 2001; 240:517-30. [PMID: 11784080 DOI: 10.1006/dbio.2001.0473] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The salivary system in mammals is comprised of three independently developed pairs of organs, the parotid, submaxillar, and sublingual glands. Each gland is composed of various ductal and acinar cell types that fulfill multiple roles. However, the molecular mechanisms regulating their biogenesis and functions are still largely unknown. In this paper, we report that two class B basic helix-loop-helix (bHLH) transcriptional regulators delineate the ductal and the acinar cells in salivary glands. Sgn1, a novel class B bHLH factor, is specifically expressed in the salivary duct cells, while the acinar cells are characterized by the expression of another class B bHLH factor, Mist1. The molecular nature of Sgn1 was also investigated: it binds to specific sequences of DNA as a dimer with a class A bHLH factor and acts as a negative transcriptional regulator against other bHLH factors. This study provides an important cue towards better understanding of the generation and function of multiple cell types in salivary glands. In addition, Sgn1 expression exhibits a reverse relationship with the development of male phenotypes, suggesting its role in gender dimorphism in the salivary glands.
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Affiliation(s)
- S Yoshida
- Department of Pathology and Tumor Biology, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
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45
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O'Neil J, Billa M, Oikemus S, Kelliher M. The DNA binding activity of TAL-1 is not required to induce leukemia/lymphoma in mice. Oncogene 2001; 20:3897-905. [PMID: 11439353 DOI: 10.1038/sj.onc.1204519] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2001] [Revised: 04/03/2001] [Accepted: 04/09/2001] [Indexed: 11/08/2022]
Abstract
Activation of the basic helix-loop-helix (bHLH) gene TAL-1 (or SCL) is the most frequent gain-of-function mutation in pediatric T cell acute lymphoblastic leukemia (T-ALL). Similarly, mis-expression of tal-1 in the thymus of transgenic mice results in the development of clonal T cell lymphoblastic leukemia. To determine the mechanism(s) of tal-1-induced leukemogenesis, we created transgenic mice expressing a DNA binding mutant of tal-1. Surprisingly, these mice develop disease, demonstrating that the DNA binding properties of tal-1 are not required to induce leukemia/lymphoma in mice. However, wild type tal-1 and the DNA binding mutant both form stable complexes with E2A proteins. In addition, tal-1 stimulates differentiation of CD8-single positive thymocytes but inhibits the development of CD4-single positive cells: effects also observed in E2A-deficient mice. Our study suggests that the bHLH protein tal-1 contributes to leukemia by interfering with E2A protein function(s).
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Affiliation(s)
- J O'Neil
- University of Massachusetts Medical School, Department of Molecular Genetics and Microbiology and the Cancer Center, 373 Plantation Street, Worcester, Massachusetts, MA 01605, USA
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46
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Staal FJ, Weerkamp F, Langerak AW, Hendriks RW, Clevers HC. Transcriptional Control of T Lymphocyte Differentiation. Stem Cells 2001; 19:165-79. [PMID: 11359942 DOI: 10.1634/stemcells.19-3-165] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Initiation of gene transcription by transcription factors (TFs) is an important regulatory step in many developmental processes. The differentiation of T cell progenitors in the thymus is tightly controlled by signaling molecules, ultimately activating nuclear TFs that regulate the expression of T lineage-specific genes. During the last 2 years, significant progress has been made in our understanding of the signaling routes and TFs operating during the earliest stages of thymic differentiation at the CD4(-)CD8(-) double negative stage. Here we will review the TF families that play an important role in differentiation of thymocytes, particularly focusing on recent new information with respect to the Tcf, bHLH, GATA, and CBF/HES TF families.
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Affiliation(s)
- F J Staal
- Department of Immunology, Erasmus University Rotterdam, Rotterdam, Netherlands.
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Chervinsky DS, Lam DH, Zhao XF, Melman MP, Aplan PD. Development and characterization of T cell leukemia cell lines established from SCL/LMO1 double transgenic mice. Leukemia 2001; 15:141-7. [PMID: 11243382 DOI: 10.1038/sj.leu.2401997] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
We have established a panel of nine immortal cell lines from T cell malignancies which arose in mice transgenic for the SCL and LMO1 genes. Cells from the primary malignancies initially grew very slowly in vitro, loosely attached to a stromal layer, before gaining the ability to proliferate independently. Upon gaining the ability to proliferate in the absence of a stromal layer, these cell lines grew rapidly, doubling every 14-23 h, to a very high density, approaching 10(7) cells/ml. Whereas the tumors which arise in SCL/LMO1 double transgenic mice are typically diploid or pseudodiploid, the cell lines were all grossly aneuploid, suggesting the possibility that additional genetic events were selected for in vitro. Given that SCL and LMO1 gene activation are both commonly seen in human patients with T cell acute lymphoblastic leukemia, these cell lines may be a useful in vitro model for the human disease.
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Affiliation(s)
- D S Chervinsky
- Department of Cancer Genetics, Roswell Park Cancer Institute, USA
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Abstract
PBX1 is a proto-oncogene that plays important roles in pattern formation during development. It was discovered as a fusion with the E2A gene after chromosomal translocations in a subset of acute leukemias. The resulting E2a-Pbx1 chimeric proteins display potent oncogenic properties that appear to require dimerization with Hox DNA binding partners. To define molecular pathways that may be impacted by E2a-Pbx1, a genetic screen consisting of neonatal retroviral infection was used to identify genes that accelerate development of T-cell tumors in E2A-PBX1 transgenic mice. Retroviral insertions in the Notch1 gene were observed in 88% of tumors arising with a shortened latency. Among these, approximately half created a NotchIC allele, encoding the intracellular, signaling portion of Notch1, suggesting a synergistic interaction between the Notch and E2a-Pbx1 pathways in oncogenesis. The remaining proviral insertions involvingNotch1 occurred in a more 3′ exon, resulting in truncating mutations that deleted the carboxy-terminal region ofNotch1 containing negative regulatory sequences (Notch1ΔC). In contrast toNotchIC, forced expression ofNotch1ΔC in transgenic mice did not perturb thymocyte growth or differentiation. However, mice transgenic for both the E2A-PBX1 and Notch1ΔC genes displayed a substantially shortened latency for tumor development compared with E2A-PBX1 single transgenic mice. These studies reveal a novel mechanism for oncogenic activation ofNotch1 and demonstrate a collaborative relationship between 2 cellular oncogenes that also contribute to cell fate determination during embryonic development.
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A carboxy-terminal deletion mutant of Notch1accelerates lymphoid oncogenesis in E2A-PBX1transgenic mice. Blood 2000. [DOI: 10.1182/blood.v96.5.1906] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Abstract
PBX1 is a proto-oncogene that plays important roles in pattern formation during development. It was discovered as a fusion with the E2A gene after chromosomal translocations in a subset of acute leukemias. The resulting E2a-Pbx1 chimeric proteins display potent oncogenic properties that appear to require dimerization with Hox DNA binding partners. To define molecular pathways that may be impacted by E2a-Pbx1, a genetic screen consisting of neonatal retroviral infection was used to identify genes that accelerate development of T-cell tumors in E2A-PBX1 transgenic mice. Retroviral insertions in the Notch1 gene were observed in 88% of tumors arising with a shortened latency. Among these, approximately half created a NotchIC allele, encoding the intracellular, signaling portion of Notch1, suggesting a synergistic interaction between the Notch and E2a-Pbx1 pathways in oncogenesis. The remaining proviral insertions involvingNotch1 occurred in a more 3′ exon, resulting in truncating mutations that deleted the carboxy-terminal region ofNotch1 containing negative regulatory sequences (Notch1ΔC). In contrast toNotchIC, forced expression ofNotch1ΔC in transgenic mice did not perturb thymocyte growth or differentiation. However, mice transgenic for both the E2A-PBX1 and Notch1ΔC genes displayed a substantially shortened latency for tumor development compared with E2A-PBX1 single transgenic mice. These studies reveal a novel mechanism for oncogenic activation ofNotch1 and demonstrate a collaborative relationship between 2 cellular oncogenes that also contribute to cell fate determination during embryonic development.
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Bayly R, LeBrun DP. Role for homodimerization in growth deregulation by E2a fusion proteins. Mol Cell Biol 2000; 20:5789-96. [PMID: 10913162 PMCID: PMC86056 DOI: 10.1128/mcb.20.16.5789-5796.2000] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2000] [Accepted: 05/22/2000] [Indexed: 11/20/2022] Open
Abstract
The oncogenic transcription factor E2a-Pbx1 is expressed in some cases of acute lymphoblastic leukemia as a result of chromosomal translocation 1;19. The early observation that E2a-Pbx1 incorporates transcriptional activation domains from E2a and a DNA-binding homeodomain from Pbx1 inspired a model in which E2a-Pbx1 promotes leukemogenic transformation of lymphoid progenitor cells through transcriptional induction of target genes defined by the Pbx1 portion of the molecule. However, the subsequent demonstration that the only known DNA-binding module on the molecule, the Pbx1 homeodomain, is dispensable for the induction of lymphoblastic lymphoma in transgenic mice called into question the contribution made by the Pbx1 portion. In this study, we have used a domain swap approach coupled with a fibroblast-based focus formation assay to evaluate further the requirement for PBX1-encoded peptide elements in growth deregulation by E2a-Pbx1. No impairment of focus formation was observed when the entire Pbx1 portion was replaced with DNA-binding/dimerization domains derived from yeast transcription factor GAL4 or GCN4. Furthermore, replacement of Pbx1 with tandem FKBP domains that mediate homodimerization in the presence of a synthetic ligand led to striking growth deregulation exclusively in the presence of the dimerizing agent. N-terminal elements encoded by E2A, including the AD1 transcriptional activation domain, were required for dimerization-induced focus formation. We conclude that transcriptional target genes defined by heterologous C-terminal DNA-binding modules are not required in growth deregulation by E2a fusion proteins. We speculate that interactions between N-terminal E2a elements and undefined proteins that could function as components of a transcriptional coactivator complex may be more important.
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Affiliation(s)
- R Bayly
- Richardson Laboratory, Department of Pathology, Queen's University, Kingston, Ontario K7L 3N6, Canada
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