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Song J, Zhang X, Lv S, Liu M, Hua X, Yue L, Wang S, He W. Age-related promoter-switch regulates Runx1 expression in adult rat hearts. BMC Cardiovasc Disord 2023; 23:541. [PMID: 37936072 PMCID: PMC10631011 DOI: 10.1186/s12872-023-03583-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Accepted: 10/27/2023] [Indexed: 11/09/2023] Open
Abstract
BACKGROUND Runt-related transcription factor-1 (RUNX1), a key member of the core-binding factor family of transcription factors, has emerged as a novel therapeutic target for cardiovascular disease. There is an urgent need to fully understand the expression pattern of Runx1 in the heart and the mechanisms by which it is controlled under normal conditions and in response to disease. The expression of Runx1 is regulated at the transcriptional level by two promoters designated P1 and P2. Alternative usage of these two promoters creates differential mRNA transcripts diversified in distribution and translational potential. While the significance of P1/P2 promoter-switch in the transcriptional control of Runx1 has been highlighted in the embryogenic process, very little is known about the level of P1- and P2-specific transcripts in adult hearts, and the underlying mechanisms controlling the promoter-switch. METHODS To amplify P1/P2 specific sequences in the heart, we used two different sense primers complementary to either P1 or P2 5'-regions to monitor the expression of P1/P2 transcripts. DNA methylation levels were assessed at the Runx1 promoter regions. Rats were grouped by age. RESULTS The expression levels of both P1- and P2-derived Runx1 transcripts were decreased in older rats when compared with that in young adults, paralleled with an age-dependent decline in Runx1 protein level. Furthermore, older rats demonstrated a higher degree of DNA methylation at Runx1 promoter regions. Alternative promoter usage was observed in hearts with increased age, as reflected by altered P1:P2 mRNA ratio. CONCLUSION Our data demonstrate that the expression of Runx1 in the heart is age-dependent and underscore the importance of gene methylation in the promoter-mediated transcriptional control of Runx1, thereby providing new insights to the role of epigenetic regulation in the heart.
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Affiliation(s)
- Jiawei Song
- Department of Physiology, West China School of Basic Medical Sciences and Forensic Medicine, Sichuan University, Chengdu, 610041, China
| | - Xiaoling Zhang
- Department of Cardiology, West China Hospital, Sichuan University, Chengdu, 610041, China
| | - Sinan Lv
- Department of Physiology, West China School of Basic Medical Sciences and Forensic Medicine, Sichuan University, Chengdu, 610041, China
| | - Meng Liu
- Department of Neurology, West China Hospital, Sichuan University, Chengdu, 610041, China
| | - Xing Hua
- Department of Neurology, West China Hospital, Sichuan University, Chengdu, 610041, China
| | - Limin Yue
- Department of Physiology, West China School of Basic Medical Sciences and Forensic Medicine, Sichuan University, Chengdu, 610041, China
| | - Si Wang
- Department of Cardiology, West China Hospital, Sichuan University, Chengdu, 610041, China
| | - Weihong He
- Department of Physiology, West China School of Basic Medical Sciences and Forensic Medicine, Sichuan University, Chengdu, 610041, China.
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2
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Gialesaki S, Bräuer-Hartmann D, Issa H, Bhayadia R, Alejo-Valle O, Verboon L, Schmell AL, Laszig S, Regényi E, Schuschel K, Labuhn M, Ng M, Winkler R, Ihling C, Sinz A, Glaß M, Hüttelmaier S, Matzk S, Schmid L, Strüwe FJ, Kadel SK, Reinhardt D, Yaspo ML, Heckl D, Klusmann JH. RUNX1 isoform disequilibrium promotes the development of trisomy 21-associated myeloid leukemia. Blood 2023; 141:1105-1118. [PMID: 36493345 PMCID: PMC10023736 DOI: 10.1182/blood.2022017619] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Revised: 11/08/2022] [Accepted: 11/22/2022] [Indexed: 12/14/2022] Open
Abstract
Gain of chromosome 21 (Hsa21) is among the most frequent aneuploidies in leukemia. However, it remains unclear how partial or complete amplifications of Hsa21 promote leukemogenesis and why children with Down syndrome (DS) (ie, trisomy 21) are particularly at risk of leukemia development. Here, we propose that RUNX1 isoform disequilibrium with RUNX1A bias is key to DS-associated myeloid leukemia (ML-DS). Starting with Hsa21-focused CRISPR-CRISPR-associated protein 9 screens, we uncovered a strong and specific RUNX1 dependency in ML-DS cells. Expression of the RUNX1A isoform is elevated in patients with ML-DS, and mechanistic studies using murine ML-DS models and patient-derived xenografts revealed that excess RUNX1A synergizes with the pathognomonic Gata1s mutation during leukemogenesis by displacing RUNX1C from its endogenous binding sites and inducing oncogenic programs in complex with the MYC cofactor MAX. These effects were reversed by restoring the RUNX1A:RUNX1C equilibrium in patient-derived xenografts in vitro and in vivo. Moreover, pharmacological interference with MYC:MAX dimerization using MYCi361 exerted strong antileukemic effects. Thus, our study highlights the importance of alternative splicing in leukemogenesis, even on a background of aneuploidy, and paves the way for the development of specific and targeted therapies for ML-DS, as well as for other leukemias with Hsa21 aneuploidy or RUNX1 isoform disequilibrium.
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Affiliation(s)
- Sofia Gialesaki
- Pediatric Hematology and Oncology, Hannover Medical School, Hannover, Germany
| | - Daniela Bräuer-Hartmann
- Pediatric Hematology and Oncology, Martin Luther University Halle-Wittenberg, Halle, Germany
| | - Hasan Issa
- Department of Pediatrics, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Raj Bhayadia
- Department of Pediatrics, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Oriol Alejo-Valle
- Pediatric Hematology and Oncology, Martin Luther University Halle-Wittenberg, Halle, Germany
| | - Lonneke Verboon
- Department of Pediatrics, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Anna-Lena Schmell
- Department of Pediatrics, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Stephanie Laszig
- Department of Pediatrics, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Enikő Regényi
- Pediatric Hematology and Oncology, Martin Luther University Halle-Wittenberg, Halle, Germany
- Max Planck Institute for Molecular Genetics, Berlin, Germany
| | - Konstantin Schuschel
- Department of Pediatrics, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Maurice Labuhn
- Pediatric Hematology and Oncology, Hannover Medical School, Hannover, Germany
| | - Michelle Ng
- Pediatric Hematology and Oncology, Martin Luther University Halle-Wittenberg, Halle, Germany
| | - Robert Winkler
- Department of Pediatrics, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Christian Ihling
- Department of Pharmaceutical Chemistry and Bioanalytics, Institute of Pharmacy, Martin Luther University Halle-Wittenberg, Halle, Germany
| | - Andrea Sinz
- Department of Pharmaceutical Chemistry and Bioanalytics, Institute of Pharmacy, Martin Luther University Halle-Wittenberg, Halle, Germany
| | - Markus Glaß
- Institute of Molecular Medicine, Martin Luther University Halle-Wittenberg, Halle, Germany
| | - Stefan Hüttelmaier
- Institute of Molecular Medicine, Martin Luther University Halle-Wittenberg, Halle, Germany
| | - Sören Matzk
- Max Planck Institute for Molecular Genetics, Berlin, Germany
| | - Lena Schmid
- Pediatric Hematology and Oncology, Hannover Medical School, Hannover, Germany
| | | | - Sofie-Katrin Kadel
- Pediatric Hematology and Oncology, Hannover Medical School, Hannover, Germany
| | - Dirk Reinhardt
- Pediatric Hematology and Oncology, Pediatrics III, University Hospital Essen, Essen, Germany
| | | | - Dirk Heckl
- Pediatric Hematology and Oncology, Martin Luther University Halle-Wittenberg, Halle, Germany
- Dirk Heckl, Pediatric Hematology and Oncology, Martin Luther University Halle-Wittenberg, Ernst-Grube-Str. 40, 06120 Halle, Germany;
| | - Jan-Henning Klusmann
- Department of Pediatrics, Goethe University Frankfurt, Frankfurt am Main, Germany
- Frankfurt Cancer Institute, Goethe University, Frankfurt am Main, Germany
- German Cancer Consortium (DKTK), Partner Site Frankfurt/Mainz and German Cancer Research Center (DKFZ), Heidelberg, Germany
- Correspondence: Jan-Henning Klusmann, Department of Pediatrics, Goethe University Frankfurt, Theodor Stern Kai 7, 60590 Frankfurt, Germany;
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3
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Thomas AL, Marsman J, Antony J, Schierding W, O’Sullivan JM, Horsfield JA. Transcriptional Regulation of RUNX1: An Informatics Analysis. Genes (Basel) 2021; 12:1175. [PMID: 34440349 PMCID: PMC8395016 DOI: 10.3390/genes12081175] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 07/26/2021] [Accepted: 07/28/2021] [Indexed: 01/04/2023] Open
Abstract
The RUNX1/AML1 gene encodes a developmental transcription factor that is an important regulator of haematopoiesis in vertebrates. Genetic disruptions to the RUNX1 gene are frequently associated with acute myeloid leukaemia. Gene regulatory elements (REs), such as enhancers located in non-coding DNA, are likely to be important for Runx1 transcription. Non-coding elements that modulate Runx1 expression have been investigated over several decades, but how and when these REs function remains poorly understood. Here we used bioinformatic methods and functional data to characterise the regulatory landscape of vertebrate Runx1. We identified REs that are conserved between human and mouse, many of which produce enhancer RNAs in diverse tissues. Genome-wide association studies detected single nucleotide polymorphisms in REs, some of which correlate with gene expression quantitative trait loci in tissues in which the RE is active. Our analyses also suggest that REs can be variant in haematological malignancies. In summary, our analysis identifies features of the RUNX1 regulatory landscape that are likely to be important for the regulation of this gene in normal and malignant haematopoiesis.
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Affiliation(s)
- Amarni L. Thomas
- Department of Pathology, Dunedin School of Medicine, University of Otago, Dunedin 9016, New Zealand; (A.L.T.); (J.A.)
| | - Judith Marsman
- Department of Cardiology, University Medical Centre Utrecht, 3584 CX Utrecht, The Netherlands;
| | - Jisha Antony
- Department of Pathology, Dunedin School of Medicine, University of Otago, Dunedin 9016, New Zealand; (A.L.T.); (J.A.)
- The Maurice Wilkins Centre for Biodiscovery, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand;
| | - William Schierding
- Liggins Institute, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand;
| | - Justin M. O’Sullivan
- The Maurice Wilkins Centre for Biodiscovery, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand;
- Liggins Institute, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand;
- MRC Lifecourse Epidemiology Unit, University of Southampton, Southampton SO17 1BJ, UK
| | - Julia A. Horsfield
- Department of Pathology, Dunedin School of Medicine, University of Otago, Dunedin 9016, New Zealand; (A.L.T.); (J.A.)
- The Maurice Wilkins Centre for Biodiscovery, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand;
- Genetics Otago Research Centre, University of Otago, Dunedin 9054, New Zealand
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4
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Morinishi L, Kochanowski K, Levine RL, Wu LF, Altschuler SJ. Loss of TET2 Affects Proliferation and Drug Sensitivity through Altered Dynamics of Cell-State Transitions. Cell Syst 2020; 11:86-94.e5. [PMID: 32619551 DOI: 10.1016/j.cels.2020.06.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Revised: 04/20/2020] [Accepted: 06/05/2020] [Indexed: 12/17/2022]
Abstract
A persistent puzzle in cancer biology is how mutations, which neither alter growth signaling pathways nor directly interfere with drug mechanism, can still recur and persist in tumors. One example is the mutation of the DNA demethylase tet methylcytosine dioxygenase 2 (TET2) in acute myeloid leukemias (AMLs) that frequently persists from diagnosis through remission and relapse, but whose fitness advantage in chemotherapy is unclear. Here, we use isogenic human AML cell lines to show that TET2 loss of function alters the dynamics of transitions between differentiated and stem-like states. A conceptual mathematical model and experimental validation suggest that these altered cell-state dynamics can benefit the cell population by slowing population decay during drug treatment and lowering the number of survivor cells needed to re-establish the initial population. These studies shed light on the functional and phenotypic effects of a TET2 mutation in AML and illustrate how a single gene mutation can alter a cells' phenotypic plasticity. A record of this paper's transparent peer review process is included in the Supplemental Information.
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Affiliation(s)
- Leanna Morinishi
- Bioinformatics Graduate Group, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Karl Kochanowski
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Ross L Levine
- Human Oncology and pathogenesis Program and Center for Hematologic Malignancies, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA; Department of Medicine, Leukemia Service, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA; Center for Epigenetics Research, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Lani F Wu
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA 94158, USA.
| | - Steven J Altschuler
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA 94158, USA.
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5
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Mevel R, Draper JE, Lie-A-Ling M, Kouskoff V, Lacaud G. RUNX transcription factors: orchestrators of development. Development 2019; 146:dev148296. [PMID: 31488508 DOI: 10.1242/dev.148296] [Citation(s) in RCA: 129] [Impact Index Per Article: 25.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
RUNX transcription factors orchestrate many different aspects of biology, including basic cellular and developmental processes, stem cell biology and tumorigenesis. In this Primer, we introduce the molecular hallmarks of the three mammalian RUNX genes, RUNX1, RUNX2 and RUNX3, and discuss the regulation of their activities and their mechanisms of action. We then review their crucial roles in the specification and maintenance of a wide array of tissues during embryonic development and adult homeostasis.
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Affiliation(s)
- Renaud Mevel
- Cancer Research UK Stem Cell Biology Group, Cancer Research UK Manchester Institute, The University of Manchester, Alderley Park, Alderley Edge, Macclesfield SK10 4TG, UK
| | - Julia E Draper
- Cancer Research UK Stem Cell Biology Group, Cancer Research UK Manchester Institute, The University of Manchester, Alderley Park, Alderley Edge, Macclesfield SK10 4TG, UK
| | - Michael Lie-A-Ling
- Cancer Research UK Stem Cell Biology Group, Cancer Research UK Manchester Institute, The University of Manchester, Alderley Park, Alderley Edge, Macclesfield SK10 4TG, UK
| | - Valerie Kouskoff
- Division of Developmental Biology & Medicine, The University of Manchester, Michael Smith Building, Oxford Road, Manchester M13 9PT, UK
| | - Georges Lacaud
- Cancer Research UK Stem Cell Biology Group, Cancer Research UK Manchester Institute, The University of Manchester, Alderley Park, Alderley Edge, Macclesfield SK10 4TG, UK
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6
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Chen B, Teng J, Liu H, Pan X, Zhou Y, Huang S, Lai M, Bian G, Mao B, Sun W, Zhou Q, Yang S, Nakahata T, Ma F. Inducible overexpression of RUNX1b/c in human embryonic stem cells blocks early hematopoiesis from mesoderm. J Mol Cell Biol 2018; 9:262-273. [PMID: 28992293 DOI: 10.1093/jmcb/mjx032] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2016] [Accepted: 08/12/2017] [Indexed: 12/16/2022] Open
Abstract
RUNX1 is absolutely required for definitive hematopoiesis, but the function of RUNX1b/c, two isoforms of human RUNX1, is unclear. We established inducible RUNX1b/c-overexpressing human embryonic stem cell (hESC) lines, in which RUNX1b/c overexpression prevented the emergence of CD34+ cells from early stage, thereby drastically reducing the production of hematopoietic stem/progenitor cells. Simultaneously, the expression of hematopoiesis-related factors was downregulated. However, such blockage effect disappeared from day 6 in hESC/AGM-S3 cell co-cultures, proving that the blockage occurred before the generation of hemogenic endothelial cells. This blockage was partially rescued by RepSox, an inhibitor of the transforming growth factor (TGF)-β signaling pathway, indicating a close relationship between RUNX1b/c and TGF-β pathway. Our results suggest a unique inhibitory function of RUNX1b/c in the development of early hematopoiesis and may aid further understanding of its biological function in normal and diseased models.
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Affiliation(s)
- B Chen
- Institute of Blood Transfusion, Chinese Academy of Medical Sciences & Peking Union Medical College (CAMS & PUMC), Chengdu 610052, China
| | - Jiawen Teng
- Institute of Blood Transfusion, Chinese Academy of Medical Sciences & Peking Union Medical College (CAMS & PUMC), Chengdu 610052, China
| | - Hongwei Liu
- Institute of Blood Transfusion, Chinese Academy of Medical Sciences & Peking Union Medical College (CAMS & PUMC), Chengdu 610052, China
| | - X Pan
- Institute of Blood Transfusion, Chinese Academy of Medical Sciences & Peking Union Medical College (CAMS & PUMC), Chengdu 610052, China
| | - Y Zhou
- Institute of Blood Transfusion, Chinese Academy of Medical Sciences & Peking Union Medical College (CAMS & PUMC), Chengdu 610052, China
| | - Shu Huang
- Institute of Blood Transfusion, Chinese Academy of Medical Sciences & Peking Union Medical College (CAMS & PUMC), Chengdu 610052, China
| | - Mowen Lai
- Institute of Blood Transfusion, Chinese Academy of Medical Sciences & Peking Union Medical College (CAMS & PUMC), Chengdu 610052, China
| | - Guohui Bian
- Institute of Blood Transfusion, Chinese Academy of Medical Sciences & Peking Union Medical College (CAMS & PUMC), Chengdu 610052, China
| | - Bin Mao
- Institute of Blood Transfusion, Chinese Academy of Medical Sciences & Peking Union Medical College (CAMS & PUMC), Chengdu 610052, China
| | - Wencui Sun
- Institute of Blood Transfusion, Chinese Academy of Medical Sciences & Peking Union Medical College (CAMS & PUMC), Chengdu 610052, China
| | - Qiongxiu Zhou
- Institute of Blood Transfusion, Chinese Academy of Medical Sciences & Peking Union Medical College (CAMS & PUMC), Chengdu 610052, China
| | - Shengyong Yang
- State Key Laboratory of Biotherapy, Sichuan University, Chengdu 610065, China
| | - Tatsutoshi Nakahata
- Center for iPS Cell Research and Application (CiRA), Kyoto University, Kyoto 606-8507, Japan
| | - Feng Ma
- Institute of Blood Transfusion, Chinese Academy of Medical Sciences & Peking Union Medical College (CAMS & PUMC), Chengdu 610052, China
- State Key Laboratory of Biotherapy, Sichuan University, Chengdu 610065, China
- State Key Laboratory of Experimental Hematology, CAMS & PUMC, Tianjin 300020, China
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7
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Lie-A-Ling M, Marinopoulou E, Lilly AJ, Challinor M, Patel R, Lancrin C, Kouskoff V, Lacaud G. Regulation of RUNX1 dosage is crucial for efficient blood formation from hemogenic endothelium. Development 2018; 145:dev149419. [PMID: 29530939 PMCID: PMC5868988 DOI: 10.1242/dev.149419] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Accepted: 01/30/2018] [Indexed: 12/20/2022]
Abstract
During ontogeny, hematopoietic stem and progenitor cells arise from hemogenic endothelium through an endothelial-to-hematopoietic transition that is strictly dependent on the transcription factor RUNX1. Although it is well established that RUNX1 is essential for the onset of hematopoiesis, little is known about the role of RUNX1 dosage specifically in hemogenic endothelium and during the endothelial-to-hematopoietic transition. Here, we used the mouse embryonic stem cell differentiation system to determine if and how RUNX1 dosage affects hemogenic endothelium differentiation. The use of inducible Runx1 expression combined with alterations in the expression of the RUNX1 co-factor CBFβ allowed us to evaluate a wide range of RUNX1 levels. We demonstrate that low RUNX1 levels are sufficient and necessary to initiate an effective endothelial-to-hematopoietic transition. Subsequently, RUNX1 is also required to complete the endothelial-to-hematopoietic transition and to generate functional hematopoietic precursors. In contrast, elevated levels of RUNX1 are able to drive an accelerated endothelial-to-hematopoietic transition, but the resulting cells are unable to generate mature hematopoietic cells. Together, our results suggest that RUNX1 dosage plays a pivotal role in hemogenic endothelium maturation and the establishment of the hematopoietic system.
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Affiliation(s)
- Michael Lie-A-Ling
- Stem Cell Biology Group, Cancer Research UK Manchester Institute, The University of Manchester, Wilmslow Road, Manchester M20 4BX, UK
| | - Elli Marinopoulou
- Stem Cell Biology Group, Cancer Research UK Manchester Institute, The University of Manchester, Wilmslow Road, Manchester M20 4BX, UK
| | - Andrew J Lilly
- Stem Cell Hematopoiesis, Cancer Research UK Manchester Institute, The University of Manchester, Wilmslow Road, Manchester M20 4BX, UK
| | - Mairi Challinor
- Stem Cell Biology Group, Cancer Research UK Manchester Institute, The University of Manchester, Wilmslow Road, Manchester M20 4BX, UK
| | - Rahima Patel
- Stem Cell Biology Group, Cancer Research UK Manchester Institute, The University of Manchester, Wilmslow Road, Manchester M20 4BX, UK
| | - Christophe Lancrin
- EMBL Rome, Epigenetics and Neurobiology Unit, Campus Adriano Buzzati-Traverso Via Ramarini 32, 00015 Monterotondo, Italy
| | - Valerie Kouskoff
- Stem Cell Hematopoiesis, Cancer Research UK Manchester Institute, The University of Manchester, Wilmslow Road, Manchester M20 4BX, UK
| | - Georges Lacaud
- Stem Cell Biology Group, Cancer Research UK Manchester Institute, The University of Manchester, Wilmslow Road, Manchester M20 4BX, UK
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8
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Nieke S, Yasmin N, Kakugawa K, Yokomizo T, Muroi S, Taniuchi I. Unique N-terminal sequences in two Runx1 isoforms are dispensable for Runx1 function. BMC DEVELOPMENTAL BIOLOGY 2017; 17:14. [PMID: 29047338 PMCID: PMC5648507 DOI: 10.1186/s12861-017-0156-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Accepted: 10/01/2017] [Indexed: 01/19/2023]
Abstract
Background The Runt-related transcription factors (Runx) are a family of evolutionarily conserved transcriptional regulators that play multiple roles in the developmental control of various cell types. Among the three mammalian Runx proteins, Runx1 is essential for definitive hematopoiesis and its dysfunction leads to human leukemogenesis. There are two promoters, distal (P1) and proximal (P2), in the Runx1 gene, which produce two Runx1 isoforms with distinct N-terminal amino acid sequences, P1-Runx1 and P2-Runx1. However, it remains unclear whether P2-Runx specific N-terminal sequence have any specific function for Runx1 protein. Results To address the function of the P2-Runx1 isoform, we established novel mutant mouse models in which the translational initiation AUG (+1) codon for P2-Runx1 isoform was modulated. We found that a truncated P2-Runx1 isoform is translated from a downstream non-canonical AUG codon. Importantly, the truncated P2-Runx1 isoform is sufficient to support primary hematopoiesis, even in the absence of the P1-Runx1 isoform. Furthermore, the truncated P2-Runx1 isoform was able to restore defect in basophil development caused by loss of the P1-Runx1 isoform. The truncated P2-Runx1 isoform was more stable than the canonical P2-Runx1 isoform. Conclusions Our results demonstrate that the N-terminal sequences specific for P2-Runx1 are dispensable for Runx1 function, and likely serve as a de-stabilization module to regulate Runx1 production. Electronic supplementary material The online version of this article (10.1186/s12861-017-0156-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Sebastian Nieke
- Laboratory for Transcriptional Regulation, RIKEN Center for Integrative Medical Sciences (IMS). 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, 230-0045, Japan.,Abteilung Immunologie, Interfakultaeres Institute fuer Zellbiologie, Auf der Morgenstelle 15, 72076, Tuebingen, Germany
| | - Nighat Yasmin
- Laboratory for Transcriptional Regulation, RIKEN Center for Integrative Medical Sciences (IMS). 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, 230-0045, Japan.,Faculty of Life Sciences (Microbiology), University of Central Punjab, 1 - Khayaban-e-Jinnah Road, Johar Town, Pakistan
| | - Kiyokazu Kakugawa
- Laboratory for Immune Crosstalk, RIKEN Center for Integrative Medical Sciences (IMS), 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, 230-0045, Japan
| | - Tomomasa Yokomizo
- Cancer Science Institute of Singapore, National University of Singapore, 14 Medical Drive, #12-01, Singapore, 117599, Singapore.,International Research Center for Medical Sciences, Kumamoto University, 2-2-1 Honjo, Chuo-ku, Kumamoto City, 860-0811, Japan
| | - Sawako Muroi
- Laboratory for Transcriptional Regulation, RIKEN Center for Integrative Medical Sciences (IMS). 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, 230-0045, Japan
| | - Ichiro Taniuchi
- Laboratory for Transcriptional Regulation, RIKEN Center for Integrative Medical Sciences (IMS). 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, 230-0045, Japan.
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9
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Draper JE, Sroczynska P, Leong HS, Fadlullah MZH, Miller C, Kouskoff V, Lacaud G. Mouse RUNX1C regulates premegakaryocytic/erythroid output and maintains survival of megakaryocyte progenitors. Blood 2017; 130:271-284. [PMID: 28490570 PMCID: PMC5833261 DOI: 10.1182/blood-2016-06-723635] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Accepted: 04/21/2017] [Indexed: 12/13/2022] Open
Abstract
RUNX1 is crucial for the regulation of megakaryocyte specification, maturation, and thrombopoiesis. Runx1 possesses 2 promoters: the distal P1 and proximal P2 promoters. The major protein isoforms generated by P1 and P2 are RUNX1C and RUNX1B, respectively, which differ solely in their N-terminal amino acid sequences. RUNX1C is the most abundantly expressed isoform in adult hematopoiesis, present in all RUNX1-expressing populations, including the cKit+ hematopoietic stem and progenitor cells. RUNX1B expression is more restricted, being highly expressed in the megakaryocyte lineage but downregulated during erythropoiesis. We generated a Runx1 P1 knock-in of RUNX1B, termed P1-MRIPV This mouse line lacks RUNX1C expression but has normal total RUNX1 levels, solely comprising RUNX1B. Using this mouse line, we establish a specific requirement for the P1-RUNX1C isoform in megakaryopoiesis, which cannot be entirely compensated for by RUNX1B overexpression. P1 knock-in megakaryocyte progenitors have reduced proliferative capacity and undergo increased cell death, resulting in thrombocytopenia. P1 knock-in premegakaryocyte/erythroid progenitors demonstrate an erythroid-specification bias, evident from increased erythroid colony-forming ability and decreased megakaryocyte output. At a transcriptional level, multiple erythroid-specific genes are upregulated and megakaryocyte-specific transcripts are downregulated. In addition, proapoptotic pathways are activated in P1 knock-in premegakaryocyte/erythroid progenitors, presumably accounting for the increased cell death in the megakaryocyte progenitor compartment. Unlike in the conditional adult Runx1 null models, megakaryocytic maturation is not affected in the P1 knock-in mice, suggesting that RUNX1B can regulate endomitosis and thrombopoiesis. Therefore, despite the high degree of structural similarity, RUNX1B and RUNX1C isoforms have distinct and specific roles in adult megakaryopoiesis.
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Affiliation(s)
- Julia E Draper
- Cancer Research UK Stem Cell Biology Group, Cancer Research UK Manchester Institute, The University of Manchester, Manchester, United Kingdom
| | - Patrycja Sroczynska
- Cancer Research UK Stem Cell Biology Group, Cancer Research UK Manchester Institute, The University of Manchester, Manchester, United Kingdom
- Biotech Research and Innovation Center and
- Center for Epigenetics, University of Copenhagen, Copenhagen, Denmark; and
| | - Hui Sun Leong
- Cancer Research UK Applied Computational Biology and Bioinformatics Group, Cancer Research UK Manchester Institute and
| | - Muhammad Z H Fadlullah
- Cancer Research UK Stem Cell Biology Group, Cancer Research UK Manchester Institute, The University of Manchester, Manchester, United Kingdom
| | - Crispin Miller
- Cancer Research UK Applied Computational Biology and Bioinformatics Group, Cancer Research UK Manchester Institute and
| | - Valerie Kouskoff
- Division of Developmental Biology & Medicine, The University of Manchester, Manchester, United Kingdom
| | - Georges Lacaud
- Cancer Research UK Stem Cell Biology Group, Cancer Research UK Manchester Institute, The University of Manchester, Manchester, United Kingdom
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10
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Runx transcription factors in the development and function of the definitive hematopoietic system. Blood 2017; 129:2061-2069. [PMID: 28179276 DOI: 10.1182/blood-2016-12-689109] [Citation(s) in RCA: 115] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Accepted: 01/29/2017] [Indexed: 01/01/2023] Open
Abstract
The Runx family of transcription factors (Runx1, Runx2, and Runx3) are highly conserved and encode proteins involved in a variety of cell lineages, including blood and blood-related cell lineages, during developmental and adult stages of life. They perform activation and repressive functions in the regulation of gene expression. The requirement for Runx1 in the normal hematopoietic development and its dysregulation through chromosomal translocations and loss-of-function mutations as found in acute myeloid leukemias highlight the importance of this transcription factor in the healthy blood system. Whereas another review will focus on the role of Runx factors in leukemias, this review will provide an overview of the normal regulation and function of Runx factors in hematopoiesis and focus particularly on the biological effects of Runx1 in the generation of hematopoietic stem cells. We will present the current knowledge of the structure and regulatory features directing lineage-specific expression of Runx genes, the models of embryonic and adult hematopoietic development that provide information on their function, and some of the mechanisms by which they affect hematopoietic function.
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11
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VanOudenhove JJ, Medina R, Ghule PN, Lian JB, Stein JL, Zaidi SK, Stein GS. Precocious Phenotypic Transcription-Factor Expression During Early Development. J Cell Biochem 2017; 118:953-958. [PMID: 27591551 DOI: 10.1002/jcb.25723] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Accepted: 09/01/2016] [Indexed: 01/20/2023]
Abstract
A novel role for phenotypic transcription factors in very early differentiation was recently observed and merits further study to elucidate what role this precocious expression may have in development. The RUNX1 transcription factor exhibits selective and transient upregulation during early mesenchymal differentiation. In contrast to phenotype-associated transcriptional control of gene expression to establish and sustain hematopoietic/myeloid lineage identity, precocious expression of RUNX1 is functionally linked to control of an epithelial to mesenchymal transition that is obligatory for development. This early RUNX1 expression spike provides a paradigm for precocious expression of a phenotypic transcription factor that invites detailed mechanistic study to fully understand its biological importance. J. Cell. Biochem. 118: 953-958, 2017. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Jennifer J VanOudenhove
- Department of Biochemistry and University of Vermont Cancer Center, University of Vermont College of Medicine, 89 Beaumont Avenue, Burlington, Vermont 05405.,Department of Cell and Developmental Biology, University of Massachusetts Medical School, 55 Lake Avenue North, Worcester, Massachusetts 01655
| | - Ricardo Medina
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, 55 Lake Avenue North, Worcester, Massachusetts 01655
| | - Prachi N Ghule
- Department of Biochemistry and University of Vermont Cancer Center, University of Vermont College of Medicine, 89 Beaumont Avenue, Burlington, Vermont 05405
| | - Jane B Lian
- Department of Biochemistry and University of Vermont Cancer Center, University of Vermont College of Medicine, 89 Beaumont Avenue, Burlington, Vermont 05405
| | - Janet L Stein
- Department of Biochemistry and University of Vermont Cancer Center, University of Vermont College of Medicine, 89 Beaumont Avenue, Burlington, Vermont 05405
| | - Sayyed K Zaidi
- Department of Biochemistry and University of Vermont Cancer Center, University of Vermont College of Medicine, 89 Beaumont Avenue, Burlington, Vermont 05405
| | - Gary S Stein
- Department of Biochemistry and University of Vermont Cancer Center, University of Vermont College of Medicine, 89 Beaumont Avenue, Burlington, Vermont 05405
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12
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Yzaguirre AD, de Bruijn MFTR, Speck NA. The Role of Runx1 in Embryonic Blood Cell Formation. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 962:47-64. [DOI: 10.1007/978-981-10-3233-2_4] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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13
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Bonifer C, Levantini E, Kouskoff V, Lacaud G. Runx1 Structure and Function in Blood Cell Development. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 962:65-81. [PMID: 28299651 DOI: 10.1007/978-981-10-3233-2_5] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
RUNX transcription factors belong to a highly conserved class of transcriptional regulators which play various roles in the development of the majority of metazoans. In this review we focus on the founding member of the family, RUNX1, and its role in the transcriptional control of blood cell development in mammals. We summarize data showing that RUNX1 functions both as activator and repressor within a chromatin environment, a feature that requires its interaction with multiple other transcription factors and co-factors. Furthermore, we outline how RUNX1 works together with other factors to reshape the epigenetic landscape and the three-dimensional structure of gene loci within the nucleus. Finally, we review how aberrant forms of RUNX1 deregulate blood cell development and cause hematopoietic malignancies.
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Affiliation(s)
- Constanze Bonifer
- Institute for Cancer and Genomic Sciences, University of Birmingham, Birmingham, UK.
| | - Elena Levantini
- Beth Israel Diaconess Medical Center, Harvard Medical School, Boston, MA, USA
- Istituto di Tecnologie Biomediche, Consiglio Nazionale delle Richerche, Pisa, Italy
| | - Valerie Kouskoff
- Division of Developmental Biology & Medicine, The University of Manchester, Manchester, UK
| | - Georges Lacaud
- Cancer Research UK Manchester Institute, University of Manchester, Manchester, UK
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14
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Differentiation of human embryonic stem cells to HOXA+ hemogenic vasculature that resembles the aorta-gonad-mesonephros. Nat Biotechnol 2016; 34:1168-1179. [DOI: 10.1038/nbt.3702] [Citation(s) in RCA: 120] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2015] [Accepted: 09/14/2016] [Indexed: 01/13/2023]
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15
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VanOudenhove JJ, Medina R, Ghule PN, Lian JB, Stein JL, Zaidi SK, Stein GS. Transient RUNX1 Expression during Early Mesendodermal Differentiation of hESCs Promotes Epithelial to Mesenchymal Transition through TGFB2 Signaling. Stem Cell Reports 2016; 7:884-896. [PMID: 27720906 PMCID: PMC5106514 DOI: 10.1016/j.stemcr.2016.09.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Revised: 09/08/2016] [Accepted: 09/09/2016] [Indexed: 12/24/2022] Open
Abstract
The transition of human embryonic stem cells (hESCs) from pluripotency to lineage commitment is not fully understood, and a role for phenotypic transcription factors in the initial stages of hESC differentiation remains to be explored. From a screen of candidate factors, we found that RUNX1 is selectively and transiently upregulated early in hESC differentiation to mesendodermal lineages. Transcriptome profiling and functional analyses upon RUNX1 depletion established a role for RUNX1 in promoting cell motility. In parallel, we discovered a loss of repression for several epithelial genes, indicating that loss of RUNX1 impaired an epithelial to mesenchymal transition during differentiation. Cell biological and biochemical approaches revealed that RUNX1 depletion specifically compromised TGFB2 signaling. Both the decrease in motility and deregulated epithelial marker expression upon RUNX1 depletion were rescued by reintroduction of TGFB2, but not TGFB1. These findings identify roles for RUNX1-TGFB2 signaling in early events of mesendodermal lineage commitment. RUNX1 is transiently upregulated during early mesendoderm differentiation of hESCs RUNX1 promotes motility and the EMT process during mesendodermal differentiation RUNX1 knockdown specifically inhibits TGFB2 signaling Reintroduction of TGFB2, but not TGFB1, rescues the phenotype of RUNX1 depletion
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Affiliation(s)
- Jennifer J VanOudenhove
- Department of Biochemistry and University of Vermont Cancer Center, University of Vermont College of Medicine, Burlington, VT 05405, USA; Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Ricardo Medina
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Prachi N Ghule
- Department of Biochemistry and University of Vermont Cancer Center, University of Vermont College of Medicine, Burlington, VT 05405, USA
| | - Jane B Lian
- Department of Biochemistry and University of Vermont Cancer Center, University of Vermont College of Medicine, Burlington, VT 05405, USA
| | - Janet L Stein
- Department of Biochemistry and University of Vermont Cancer Center, University of Vermont College of Medicine, Burlington, VT 05405, USA
| | - Sayyed K Zaidi
- Department of Biochemistry and University of Vermont Cancer Center, University of Vermont College of Medicine, Burlington, VT 05405, USA
| | - Gary S Stein
- Department of Biochemistry and University of Vermont Cancer Center, University of Vermont College of Medicine, Burlington, VT 05405, USA.
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16
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Martinez M, Hinojosa M, Trombly D, Morin V, Stein J, Stein G, Javed A, Gutierrez SE. Transcriptional Auto-Regulation of RUNX1 P1 Promoter. PLoS One 2016; 11:e0149119. [PMID: 26901859 PMCID: PMC4762634 DOI: 10.1371/journal.pone.0149119] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Accepted: 01/27/2016] [Indexed: 12/11/2022] Open
Abstract
RUNX1 a member of the family of runt related transcription factors (RUNX), is essential for hematopoiesis. The expression of RUNX1 gene is controlled by two promoters; the distal P1 promoter and the proximal P2 promoter. Several isoforms of RUNX1 mRNA are generated through the use of both promoters and alternative splicing. These isoforms not only differs in their temporal expression pattern but also exhibit differences in tissue specificity. The RUNX1 isoforms derived from P2 are expressed in a variety of tissues, but expression of P1-derived isoform is restricted to cells of hematopoietic lineage. However, the control of hematopoietic-cell specific expression is poorly understood. Here we report regulation of P1-derived RUNX1 mRNA by RUNX1 protein. In silico analysis of P1 promoter revealed presence of two evolutionary conserved RUNX motifs, 0.6kb upstream of the transcription start site, and three RUNX motifs within 170bp of the 5'UTR. Transcriptional contribution of these RUNX motifs was studied in myeloid and T-cells. RUNX1 genomic fragment containing all sites show very low basal activity in both cell types. Mutation or deletion of RUNX motifs in the UTR enhances basal activity of the RUNX1 promoter. Chromatin immunoprecipitation revealed that RUNX1 protein is recruited to these sites. Overexpression of RUNX1 in non-hematopoietic cells results in a dose dependent activation of the RUNX1 P1 promoter. We also demonstrate that RUNX1 protein regulates transcription of endogenous RUNX1 mRNA in T-cell. Finally we show that SCL transcription factor is recruited to regions containing RUNX motifs in the promoter and the UTR and regulates activity of the RUNX1 P1 promoter in vitro. Thus, multiple lines of evidence show that RUNX1 protein regulates its own gene transcription.
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Affiliation(s)
- Milka Martinez
- Departamento de Bioquimica y Biologia Molecular, Facultad de Ciencias Biologicas, Universidad de Concepcion, Concepcion, Chile
| | - Marcela Hinojosa
- Departamento de Bioquimica y Biologia Molecular, Facultad de Ciencias Biologicas, Universidad de Concepcion, Concepcion, Chile
| | - Daniel Trombly
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, 55 Lake Avenue North, Worcester, 01655, Massachusetts, United States of America
| | - Violeta Morin
- Departamento de Bioquimica y Biologia Molecular, Facultad de Ciencias Biologicas, Universidad de Concepcion, Concepcion, Chile
| | - Janet Stein
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, 55 Lake Avenue North, Worcester, 01655, Massachusetts, United States of America
- Department of Biochemistry and Vermont Cancer Center, University of Vermont College of Medicine, 89 Beaumont Avenue, Burlington 05405, Vermont, United States of America
| | - Gary Stein
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, 55 Lake Avenue North, Worcester, 01655, Massachusetts, United States of America
- Department of Biochemistry and Vermont Cancer Center, University of Vermont College of Medicine, 89 Beaumont Avenue, Burlington 05405, Vermont, United States of America
| | - Amjad Javed
- Department of Oral and Maxillofacial Surgery, School of Dentistry, University of Alabama at Birmingham, Alabama, United States of America
| | - Soraya E. Gutierrez
- Departamento de Bioquimica y Biologia Molecular, Facultad de Ciencias Biologicas, Universidad de Concepcion, Concepcion, Chile
- * E-mail:
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17
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Ferrell PI, Xi J, Ma C, Adlakha M, Kaufman DS. The RUNX1 +24 enhancer and P1 promoter identify a unique subpopulation of hematopoietic progenitor cells derived from human pluripotent stem cells. Stem Cells 2016; 33:1130-41. [PMID: 25546363 DOI: 10.1002/stem.1940] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Revised: 11/14/2014] [Accepted: 12/03/2014] [Indexed: 12/20/2022]
Abstract
Derivation of hematopoietic stem cells (HSCs) from human pluripotent stem cells remains a key goal for the fields of developmental biology and regenerative medicine. Here, we use a novel genetic reporter system to prospectively identify and isolate early hematopoietic cells derived from human embryonic stem cells (hESCs) and human induced pluripotent cells (iPSCs). Cloning the human RUNX1c P1 promoter and +24 enhancer to drive expression of tdTomato (tdTom) in hESCs and iPSCs, we demonstrate that tdTom expression faithfully enriches for RUNX1c-expressing hematopoietic progenitor cells. Time-lapse microscopy demonstrated the tdTom(+) hematopoietic cells to emerge from adherent cells. Furthermore, inhibition of primitive hematopoiesis by blocking Activin/Nodal signaling promoted the expansion and/or survival of the tdTom(+) population. Notably, RUNX1c/tdTom(+) cells represent only a limited subpopulation of the CD34(+) CD45(+) and CD34(+) CD43(+) cells with a unique genetic signature. Using gene array analysis, we find significantly lower expression of Let-7 and mir181a microRNAs in the RUNX1c/tdTom(+) cell population. These phenotypic and genetic analyses comparing the RUNX1c/tdTom(+) population to CD34(+) CD45(+) umbilical cord blood and fetal liver demonstrate several key differences that likely impact the development of HSCs capable of long-term multilineage engraftment from hESCs and iPSCs.
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Affiliation(s)
- Patrick I Ferrell
- Department of Medicine, University of Minnesota, Minneapolis, Minnesota, USA; Stem Cell Institute, University of Minnesota, Minneapolis, Minnesota, USA
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18
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Draper JE, Sroczynska P, Tsoulaki O, Leong HS, Fadlullah MZH, Miller C, Kouskoff V, Lacaud G. RUNX1B Expression Is Highly Heterogeneous and Distinguishes Megakaryocytic and Erythroid Lineage Fate in Adult Mouse Hematopoiesis. PLoS Genet 2016; 12:e1005814. [PMID: 26808730 PMCID: PMC4726605 DOI: 10.1371/journal.pgen.1005814] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Accepted: 12/23/2015] [Indexed: 12/11/2022] Open
Abstract
The Core Binding Factor (CBF) protein RUNX1 is a master regulator of definitive hematopoiesis, crucial for hematopoietic stem cell (HSC) emergence during ontogeny. RUNX1 also plays vital roles in adult mice, in regulating the correct specification of numerous blood lineages. Akin to the other mammalian Runx genes, Runx1 has two promoters P1 (distal) and P2 (proximal) which generate distinct protein isoforms. The activities and specific relevance of these two promoters in adult hematopoiesis remain to be fully elucidated. Utilizing a dual reporter mouse model we demonstrate that the distal P1 promoter is broadly active in adult hematopoietic stem and progenitor cell (HSPC) populations. By contrast the activity of the proximal P2 promoter is more restricted and its upregulation, in both the immature Lineage- Sca1high cKithigh (LSK) and bipotential Pre-Megakaryocytic/Erythroid Progenitor (PreMegE) populations, coincides with a loss of erythroid (Ery) specification. Accordingly the PreMegE population can be prospectively separated into "pro-erythroid" and "pro-megakaryocyte" populations based on Runx1 P2 activity. Comparative gene expression analyses between Runx1 P2+ and P2- populations indicated that levels of CD34 expression could substitute for P2 activity to distinguish these two cell populations in wild type (WT) bone marrow (BM). Prospective isolation of these two populations will enable the further investigation of molecular mechanisms involved in megakaryocytic/erythroid (Mk/Ery) cell fate decisions. Having characterized the extensive activity of P1, we utilized a P1-GFP homozygous mouse model to analyze the impact of the complete absence of Runx1 P1 expression in adult mice and observed strong defects in the T cell lineage. Finally, we investigated how the leukemic fusion protein AML1-ETO9a might influence Runx1 promoter usage. Short-term AML1-ETO9a induction in BM resulted in preferential P2 upregulation, suggesting its expression may be important to establish a pre-leukemic environment.
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Affiliation(s)
- Julia E. Draper
- Cancer Research UK Stem Cell Biology Group, Cancer Research UK Manchester Institute, The University of Manchester, Manchester, United Kingdom
| | - Patrycja Sroczynska
- Cancer Research UK Stem Cell Biology Group, Cancer Research UK Manchester Institute, The University of Manchester, Manchester, United Kingdom
- Biotech Research and Innovation Centre, University of Copenhagen, Copenhagen, Denmark
- Centre for Epigenetics, University of Copenhagen, Copenhagen, Denmark
| | - Olga Tsoulaki
- Cancer Research UK Stem Cell Biology Group, Cancer Research UK Manchester Institute, The University of Manchester, Manchester, United Kingdom
| | - Hui Sun Leong
- Cancer Research UK Applied Computational Biology and Bioinformatics Group, Cancer Research UK Manchester Institute, The University of Manchester, Manchester, United Kingdom
| | - Muhammad Z. H. Fadlullah
- Cancer Research UK Stem Cell Biology Group, Cancer Research UK Manchester Institute, The University of Manchester, Manchester, United Kingdom
| | - Crispin Miller
- Cancer Research UK Applied Computational Biology and Bioinformatics Group, Cancer Research UK Manchester Institute, The University of Manchester, Manchester, United Kingdom
| | - Valerie Kouskoff
- Cancer Research UK Stem Cell Haematopoiesis Group, Cancer Research UK Manchester Institute, The University of Manchester, Manchester, United Kingdom
| | - Georges Lacaud
- Cancer Research UK Stem Cell Biology Group, Cancer Research UK Manchester Institute, The University of Manchester, Manchester, United Kingdom
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19
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20
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Marsman J, O'Neill AC, Kao BRY, Rhodes JM, Meier M, Antony J, Mönnich M, Horsfield JA. Cohesin and CTCF differentially regulate spatiotemporal runx1 expression during zebrafish development. BIOCHIMICA ET BIOPHYSICA ACTA 2014; 1839:50-61. [PMID: 24321385 DOI: 10.1016/j.bbagrm.2013.11.007] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2013] [Revised: 11/19/2013] [Accepted: 11/25/2013] [Indexed: 11/23/2022]
Abstract
Runx1 is a transcription factor essential for definitive hematopoiesis. In all vertebrates, the Runx1 gene is transcribed from two promoters: a proximal promoter (P2), and a distal promoter (P1). We previously found that runx1 expression in a specific hematopoietic cell population in zebrafish embryos depends on cohesin. Here we show that zebrafish runx1 is directly bound by cohesin and CCCTC binding factor (CTCF) at the P1 and P2 promoters, and within the intron between P1 and P2. Cohesin initiates expression of runx1 in the posterior lateral mesoderm and influences promoter use, while CTCF represses its expression in the newly emerging cells of the tail bud. The intronic binding sites for cohesin and CTCF coincide with histone modifications that confer enhancer-like properties, and two of the cohesin/CTCF sites behaved as insulators in an in vivo assay. The identified cohesin and CTCF binding sites are likely to be cis-regulatory elements (CREs) for runx1 since they also recruit RNA polymerase II (RNAPII). CTCF depletion excluded RNAPII from two intronic CREs but not the promoters of runx1. We propose that cohesin and CTCF have distinct functions in the regulation of runx1 during zebrafish embryogenesis, and that these regulatory functions are likely to involve runx1 intronic CREs. Cohesin (but not CTCF) depletion enhanced RUNX1 expression in a human leukemia cell line, suggesting conservation of RUNX1 regulation through evolution.
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Affiliation(s)
- Judith Marsman
- Department of Pathology, Dunedin School of Medicine, The University of Otago, P.O. Box 913, Dunedin, New Zealand
| | - Adam C O'Neill
- Department of Pathology, Dunedin School of Medicine, The University of Otago, P.O. Box 913, Dunedin, New Zealand
| | - Betty Rui-Yun Kao
- Department of Pathology, Dunedin School of Medicine, The University of Otago, P.O. Box 913, Dunedin, New Zealand
| | - Jenny M Rhodes
- Department of Pathology, Dunedin School of Medicine, The University of Otago, P.O. Box 913, Dunedin, New Zealand
| | - Michael Meier
- Department of Pathology, Dunedin School of Medicine, The University of Otago, P.O. Box 913, Dunedin, New Zealand
| | - Jisha Antony
- Department of Pathology, Dunedin School of Medicine, The University of Otago, P.O. Box 913, Dunedin, New Zealand
| | - Maren Mönnich
- Department of Pathology, Dunedin School of Medicine, The University of Otago, P.O. Box 913, Dunedin, New Zealand
| | - Julia A Horsfield
- Department of Pathology, Dunedin School of Medicine, The University of Otago, P.O. Box 913, Dunedin, New Zealand.
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21
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Webber BR, Iacovino M, Choi SH, Tolar J, Kyba M, Blazar BR. DNA methylation of Runx1 regulatory regions correlates with transition from primitive to definitive hematopoietic potential in vitro and in vivo. Blood 2013; 122:2978-86. [PMID: 24030384 PMCID: PMC3811172 DOI: 10.1182/blood-2013-03-489369] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2013] [Accepted: 09/03/2013] [Indexed: 12/11/2022] Open
Abstract
The transcription factor Runx1 (AML1) is a central regulator of hematopoiesis and is required for the formation of definitive hematopoietic stem cells (HSCs). Runx1 is alternatively expressed from two promoters: the proximal (P2) prevails during primitive hematopoiesis, while the distal (P1) dominates in definitive HSCs. Although some transcription factor binding sites and cis-regulatory elements have been identified, a mechanistic explanation for the alternative promoter usage remains elusive. We investigated DNA methylation of known Runx1 cis-elements at stages of hematopoietic development in vivo and during differentiation of murine embryonic stem cells (ESCs) in vitro. In vivo, we find loss of methylation correlated with the primitive to definitive transition at the P1 promoter. In vitro, hypomethylation, acquisition of active chromatin modifications, and increased transcriptional activity at P1 are promoted by direct interaction with HOXB4, a transcription factor that confers definitive repopulation status on primitive hematopoietic progenitors. These data demonstrate a novel role for DNA methylation in the alternative promoter usage at the Runx1 locus and identify HOXB4 as a direct activator of the P1 promoter. This epigenetic signature should serve as a novel biomarker of HSC potential in vivo, and during ESC differentiation in vitro.
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Affiliation(s)
- Beau R Webber
- Division of Hematology-Oncology, Blood and Marrow Transplantation, and
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22
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Logan TT, Villapol S, Symes AJ. TGF-β superfamily gene expression and induction of the Runx1 transcription factor in adult neurogenic regions after brain injury. PLoS One 2013; 8:e59250. [PMID: 23555640 PMCID: PMC3605457 DOI: 10.1371/journal.pone.0059250] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2012] [Accepted: 02/13/2013] [Indexed: 12/17/2022] Open
Abstract
Traumatic brain injury (TBI) increases neurogenesis in the forebrain subventricular zone (SVZ) and the hippocampal dentate gyrus (DG). Transforming growth factor-β (TGF-β) superfamily cytokines are important regulators of adult neurogenesis, but their involvement in the regulation of this process after brain injury is unclear. We subjected adult mice to controlled cortical impact (CCI) injury, and isolated RNA from the SVZ and DG at different post-injury time points. qPCR array analysis showed that cortical injury caused significant alterations in the mRNA expression of components and targets of the TGF-β, BMP, and activin signaling pathways in the SVZ and DG after injury, suggesting that these pathways could regulate post-injury neurogenesis. In both neurogenic regions, the injury also induced expression of Runt-related transcription factor-1 (Runx1), which can interact with intracellular TGF-β Smad signaling pathways. CCI injury strongly induced Runx1 expression in activated and proliferating microglial cells throughout the neurogenic regions. Runx1 protein was also expressed in a subset of Nestin- and GFAP-expressing putative neural stem or progenitor cells in the DG and SVZ after injury. In the DG only, these Runx1+ progenitors proliferated. Our data suggest potential roles for Runx1 in the processes of microglial cell activation and proliferation and in neural stem cell proliferation after TBI.
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Affiliation(s)
- Trevor T. Logan
- Department of Pharmacology, Uniformed Services University of the Health Sciences, Bethesda, Maryland, United States of America
- Center for Neuroscience and Regenerative Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland, United States of America
| | - Sonia Villapol
- Department of Pharmacology, Uniformed Services University of the Health Sciences, Bethesda, Maryland, United States of America
- Center for Neuroscience and Regenerative Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland, United States of America
| | - Aviva J. Symes
- Department of Pharmacology, Uniformed Services University of the Health Sciences, Bethesda, Maryland, United States of America
- Center for Neuroscience and Regenerative Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland, United States of America
- * E-mail:
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23
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Brady G, Elgueta Karstegl C, Farrell PJ. Novel function of the unique N-terminal region of RUNX1c in B cell growth regulation. Nucleic Acids Res 2012; 41:1555-68. [PMID: 23254331 PMCID: PMC3561965 DOI: 10.1093/nar/gks1273] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
RUNX family proteins are expressed from alternate promoters, giving rise to different N-terminal forms, but the functional difference of these isoforms is not understood. Here, we show that growth of a human B lymphoblastoid cell line infected with Epstein-Barr virus is inhibited by RUNX1c but not by RUNX1b. This gives a novel functional assay for the unique N-terminus of RUNX1c, and amino acids of RUNX1c required for the effect have been identified. Primary resting B cells contain RUNX1c, consistent with the growth inhibitory effect in B cells. The oncogene TEL-RUNX1 lacks the N-terminus of RUNX1c because of the TEL fusion and does not inhibit B cell growth. Mouse Runx1c lacks some of the sequences required for human RUNX1c to inhibit B cell growth, indicating that this aspect of human B cell growth control may differ in mice. Remarkably, a cell-penetrating peptide containing the N-terminal sequence of RUNX1c specifically antagonizes the growth inhibitory effect in B lymphoblastoid cells and might be used to modulate the function of human RUNX1c.
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Affiliation(s)
- Gareth Brady
- Section of Virology, Imperial College Faculty of Medicine, Norfolk Place, London W2 1PG, UK
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24
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Markova EN, Kantidze OL, Razin SV. Transcription of the AML1/ETO chimera is guided by the P2 promoter of the AML1 gene in the Kasumi-1 cell line. Gene 2012; 510:142-6. [PMID: 22995345 DOI: 10.1016/j.gene.2012.09.028] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2012] [Revised: 08/31/2012] [Accepted: 09/07/2012] [Indexed: 02/06/2023]
Abstract
Chromosomal translocation t (8;21)(q22;22) is one of the most frequent cytogenetic abnormalities found in acute myeloid leukaemia (AML). It generates the AML1/ETO fusion gene, which itself supports human haematopoietic stem cell self-renewal. However, the mechanism guiding transcription of this chimeric gene remains unclear. In our work, we attempted to shed light on this essential issue. We investigated the promoter from which transcription of the AML1/ETO gene is initiated and defined the three-dimensional structure of the whole rearranged locus.
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Affiliation(s)
- Elena N Markova
- Laboratory of Structural and Functional Organization of Chromosomes, Institute of Gene Biology RAS, 34/5 Vavilova Street, 119334 Moscow, Russia
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Swiers G, de Bruijn M, Speck NA. Hematopoietic stem cell emergence in the conceptus and the role of Runx1. THE INTERNATIONAL JOURNAL OF DEVELOPMENTAL BIOLOGY 2011; 54:1151-63. [PMID: 20711992 DOI: 10.1387/ijdb.103106gs] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Hematopoietic stem cells (HSCs) are functionally defined as cells that upon transplantation into irradiated or otherwise immunocompromised adult organisms provide long-term reconstitution of the entire hematopoietic system. They emerge in the vertebrate conceptus around midgestation. Genetic studies have identified a number of transcription factors and signaling molecules that act at the onset of hematopoiesis, and have begun to delineate the molecular mechanisms underlying the formation of HSCs. One molecule that has been a particularly useful marker of this developmental event in multiple species is Runx1 (also known as AML1, Pebp2alpha). Runx1 is a sequence-specific DNA-binding protein, that along with its homologues Runx2 and Runx3 and their shared non-DNA binding subunit CBFbeta, constitute a small family of transcription factors called core-binding factors (CBFs). Runx1 is famous for its role in HSC emergence, and notorious for its involvement in leukemia, as chromosomal rearrangements and inactivating mutations in the human RUNX1 gene are some of the most common events in de novo and therapy-related acute myelogenous leukemia, myelodysplastic syndrome and acute lymphocytic leukemia. Here we will review the role of Runx1 in HSC emergence in the mouse conceptus and describe some of the genetic pathways that operate upstream and downstream of this gene. Where relevant, we will include data obtained from other species and embryonic stem (ES) cell differentiation cultures.
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Affiliation(s)
- Gemma Swiers
- Medical Research Council (MRC) Molecular Haematology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
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Challen GA, Goodell MA. Runx1 isoforms show differential expression patterns during hematopoietic development but have similar functional effects in adult hematopoietic stem cells. Exp Hematol 2010; 38:403-16. [PMID: 20206228 DOI: 10.1016/j.exphem.2010.02.011] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2009] [Revised: 02/25/2010] [Accepted: 02/25/2010] [Indexed: 12/27/2022]
Abstract
OBJECTIVE RUNX1 (also known as acute myeloid leukemia 1) is an essential regulator of hematopoiesis and has multiple isoforms arising from differential splicing and utilization of two promoters. We hypothesized that the rare Runx1c isoform has a distinct role in hematopoietic stem cells (HSCs). MATERIALS AND METHODS We have characterized the expression pattern of Runx1c in mouse embryos and human embryonic stem cell (hESC)-derived embryoid bodies using in situ hybridization and expression levels in mouse and human HSCs by real-time polymerase chain reaction. We then determined the functional effects of Runx1c using enforced retroviral overexpression in mouse HSCs. RESULTS We observed differential expression profiles of RUNX1 isoforms during hematopoietic differentiation of hESCs. The RUNX1a and RUNX1b isoforms were expressed consistently throughout hematopoietic differentiation, whereas the RUNX1c isoform was only expressed at the time of emergence of definitive HSCs. RUNX1c was also expressed in the AGM region of E10.5 to E11.5 mouse embryos, the region where definitive HSCs arise. These observations suggested that the RUNX1c isoform may be important for the specification or function of definitive HSCs. However, using retroviral overexpression to study the effect of RUNX1 isoforms on HSCs in a gain-of-function system, no discernable functional difference could be identified between RUNX1 isoforms in mouse HSCs. Overexpression of both RUNX1b and RUNX1c induced quiescence in mouse HSCs in vitro and in vivo. CONCLUSIONS Although the divergent expression profiles of Runx1 isoforms during development suggest specific roles for these proteins at different stages of HSC maturation, we could not detect an important functional distinction in adult mouse HSCs using our assay systems.
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Affiliation(s)
- Grant A Challen
- Stem Cells and Regenerative Medicine Center, Baylor College of Medicine, Houston, Tex. 77030, USA
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Nonredundant roles for Runx1 alternative promoters reflect their activity at discrete stages of developmental hematopoiesis. Blood 2010; 115:3042-50. [PMID: 20139099 DOI: 10.1182/blood-2009-08-238626] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The transcription factor Runx1 is a pivotal regulator of definitive hematopoiesis in mouse ontogeny. Vertebrate Runx1 is transcribed from 2 promoters, the distal P1 and proximal P2, which provide a paradigm of the complex transcriptional and translational control of Runx1 function. However, very little is known about the biologic relevance of alternative Runx1 promoter usage in definitive hematopoietic cell emergence. Here we report that both promoters are active at the very onset of definitive hematopoiesis, with a skewing toward the P2. Moreover, functional and morphologic analysis of a novel P1-null and an attenuated P2 mouse model revealed that although both promoters play important nonredundant roles in the emergence of definitive hematopoietic cells, the proximal P2 was most critically required for this. The nature of the observed phenotypes is indicative of a differential contribution of the P1 and P2 promoters to the control of overall Runx1 levels, where and when this is most critically required. In addition, the dynamic expression of P1-Runx1 and P2-Runx1 points at a requirement for Runx1 early in development, when the P2 is still the prevalent promoter in the emerging hemogenic endothelium and/or first committed hematopoietic cells.
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The differential activities of Runx1 promoters define milestones during embryonic hematopoiesis. Blood 2009; 114:5279-89. [PMID: 19858498 DOI: 10.1182/blood-2009-05-222307] [Citation(s) in RCA: 91] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The transcription factor RUNX1/AML1 is a master regulator of hematopoietic development. Its spatiotemporal expression is tightly regulated during embryonic development and is under the control of 2 alternative promoters, distal and proximal. Despite the functional significance of Runx1, the relative and specific activities of these 2 promoters remain largely uncharacterized. To investigate these activities, we introduced 2 reporter genes under the control of the proximal and distal promoters in embryonic stem cell and transgenic mouse lines. Our study reveals that both in vitro and in vivo the proximal Runx1 isoform marks a hemogenic endothelium cell population, whereas the subsequent expression of distal Runx1 defines fully committed definitive hematopoietic progenitors. Interestingly, hematopoietic commitment in distal Runx1 knockout embryos appears normal. Altogether, our data demonstrate that the differential activities of the 2 Runx1 promoters define milestones of hematopoietic development and suggest that the proximal isoform plays a critical role in the generation of hematopoietic cells from hemogenic endothelium. Identification and access to the discrete stages of hematopoietic development defined by the activities of the Runx1 promoters will provide the opportunity to further explore the cellular and molecular mechanisms of hematopoietic development.
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Fu RH, Liu SP, Ou CW, Yu HH, Li KW, Tsai CH, Shyu WC, Lin SZ. Alternative Splicing Modulates Stem Cell Differentiation. Cell Transplant 2009; 18:1029-38. [PMID: 19523332 DOI: 10.3727/096368909x471260] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Stem cells have the surprising potential to develop into many different cell types. Therefore, major research efforts have focused on transplantation of stem cells and/or derived progenitors for restoring depleted diseased cells in degenerative disorders. Understanding the molecular controls, including alternative splicing, that arise during lineage differentiation of stem cells is crucial for developing stem cell therapeutic approaches in regeneration medicine. Alternative splicing to allow a single gene to encode multiple transcripts with different protein coding sequences and RNA regulatory elements increases genomic complexities. Utilizing differences in alternative splicing as a molecular marker may be more sensitive than simply gene expression in various degrees of stem cell differentiation. Moreover, alternative splicing maybe provide a new concept to acquire induced pluripotent stem cells or promote cell–cell transdifferentiation for restorative therapies and basic medicine researches. In this review, we highlight the recent advances of alternative splicing regulation in stem cells and their progenitors. It will hopefully provide much needed knowledge into realizing stem cell biology and related applications.
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Affiliation(s)
- Ru-Huei Fu
- Center for Neuropsychiatry, China Medical University Hospital, Taichung, Taiwan
- Graduate Institute of Immunology, China Medical University, Taichung, Taiwan
| | - Shih-Ping Liu
- Center for Neuropsychiatry, China Medical University Hospital, Taichung, Taiwan
- Graduate Institute of Basic Medical Science, China Medical University, Taichung, Taiwan
| | - Chen-Wei Ou
- Graduate Institute of Immunology, China Medical University, Taichung, Taiwan
| | - Hsiu-Hui Yu
- Center for Neuropsychiatry, China Medical University Hospital, Taichung, Taiwan
| | - Kuo-Wei Li
- Center for Neuropsychiatry, China Medical University Hospital, Taichung, Taiwan
| | - Chang-Hai Tsai
- Department of Pediatrics, China Medical University Hospital, Taichung, Taiwan
- Department of Healthcare Administration, Asia University, Taichung, Taiwan
| | - Woei-Cherng Shyu
- Center for Neuropsychiatry, China Medical University Hospital, Taichung, Taiwan
- Graduate Institute of Immunology, China Medical University, Taichung, Taiwan
| | - Shinn-Zong Lin
- Center for Neuropsychiatry, China Medical University Hospital, Taichung, Taiwan
- Graduate Institute of Immunology, China Medical University, Taichung, Taiwan
- China Medical University Beigang Hospital, Yunlin, Taiwan
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Abstract
Runx1 binds DNA in cooperation with CBFbeta to activate or repress transcription, dependent upon cellular context and interaction with a variety of co-activators and co-repressors. Runx1 is required for emergence of adult hematopoietic stem cells (HSC) during embryonic development and for lymphoid, myeloid, and megakaryocyte lineage maturation from HSC in adult marrow. Runx1 levels vary during the cell cycle, and Runx1 regulates G1 to S cell cycle progression. Both Cdk and ERK phosphorylate Runx1 to influence its interaction with co-repressors, and the Wnt effector LEF-1/TCF also modulates Runx1 activities. These links likely allow cytokines and signals from adjacent cells to influence HSC proliferation versus quiescence and the rate of progenitor expansion, in response to developmental or environmental demands. J. Cell. Physiol. 219: 520-524, 2009. (c) 2009 Wiley-Liss, Inc.
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Affiliation(s)
- Alan D Friedman
- Division of Pediatric Oncology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
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Alternative Runx1 promoter usage in mouse developmental hematopoiesis. Blood Cells Mol Dis 2009; 43:35-42. [PMID: 19464215 DOI: 10.1016/j.bcmd.2009.03.011] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2009] [Accepted: 03/31/2009] [Indexed: 11/23/2022]
Abstract
The interest in stem cell based therapies has emphasized the importance of understanding the cellular and molecular mechanisms by which stem cells are generated in ontogeny and maintained throughout adult life. Hematopoietic stem cells (HSCs) are first found in clusters of hematopoietic cells budding from the luminal wall of the major arteries in the developing mammalian embryo. The transcription factor Runx1 is critical for their generation and is specifically expressed at sites of HSC generation, prior to their formation. To understand better the transcriptional hierarchies that converge on Runx1 during HSC emergence, we have initiated studies into its transcriptional regulation. Here we systematically analyzed Runx1 P1 and P2 alternative promoter usage in hematopoietic sites and in sorted cell populations during mouse hematopoietic development. Our results indicate that Runx1 expression in primitive erythrocytes is largely P2-derived, whilst in definitive hematopoietic stem and/or progenitor cells from the yolk sac or AGM and vitelline and umbilical arteries both the distal P1 and proximal P2 promoters are active. After cells have migrated to the fetal liver, the P1 gradually becomes the main hematopoietic promoter and remains this into adulthood. In addition, we identified a novel P2-derived Runx1 isoform.
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Sakai E, Kitajima K, Sato A, Nakano T. Increase of hematopoietic progenitor and suppression of endothelial gene expression by Runx1 expression during in vitro ES differentiation. Exp Hematol 2009; 37:334-45. [PMID: 19218012 DOI: 10.1016/j.exphem.2008.11.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2008] [Revised: 11/12/2008] [Accepted: 11/13/2008] [Indexed: 11/16/2022]
Abstract
OBJECTIVE Runx1 is essential for both the establishment of hematopoiesis during development and maintenance of adult hematopoiesis. To reveal the roles of Runx1, we examined how and when Runx1 functions during development of hematopoiesis, and revealed the genes controlled by Runx1. MATERIALS AND METHODS A combined in vitro approach involving in vitro hematopoietic differentiation of embryonic stem cells and conditional gene expression of Runx1 was utilized for this study. Then we analyzed the effects of Runx1 on the differentiation and proliferation of hematopoietic cells and carried out DNA microarray analysis. RESULTS Pulse expression of Runx1 prior to the emergence of hematopoietic cells caused immature hematopoietic cell increase but did not have any effects on the induction of hemogenic cells. During this process, the mRNA level of several endothelial cell-specific genes was downregulated. CONCLUSION Runx1 expression play important roles on the proliferation of emerging immature hematopoietic progenitors or the transition process from endothelial to hematopoietic cells presumably by suppressing the genes related to endothelial phenotype.
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Affiliation(s)
- Eiko Sakai
- Department of Pathology, School of Medicine and Frontier Biosciences, Osaka University, Yamadaok, Osaka, Japan.
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33
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The mouse Runx1 +23 hematopoietic stem cell enhancer confers hematopoietic specificity to both Runx1 promoters. Blood 2009; 113:5121-4. [PMID: 19321859 DOI: 10.1182/blood-2008-12-193003] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The transcription factor Runx1 plays a pivotal role in hematopoietic stem cell (HSC) emergence, and studies into its transcriptional regulation should give insight into the critical steps of HSC specification. Recently, we identified the Runx1 +23 enhancer that targets reporter gene expression to the first emerging HSCs of the mouse embryo when linked to the heterologous hsp68 promoter. Endogenous Runx1 is transcribed from 2 alternative promoters, P1 and P2. Here, we examined the in vivo cis-regulatory potential of these alternative promoters and asked whether they act with and contribute to the spatiotemporal specific expression of the Runx1 +23 enhancer. Our results firmly establish that, in contrast to zebrafish runx1, mouse Runx1 promoter sequences do not confer any hematopoietic specificity in transgenic embryos. Yet, both mouse promoters act with the +23 enhancer to drive reporter gene expression to sites of HSC emergence and colonization, in a +23-specific pattern.
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RUNX1 permits E4orf6-directed nuclear localization of the adenovirus E1B-55K protein and associates with centers of viral DNA and RNA synthesis. J Virol 2008; 82:6395-408. [PMID: 18417565 DOI: 10.1128/jvi.00043-08] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The localization of the adenovirus E1B-55K-E4orf6 protein complex is critical for its function. Prior studies demonstrated that E4orf6 directs the nuclear localization of E1B-55K in human cells and in rodent cells that contain part of human chromosome 21. We show here that the relevant activity on chromosome 21 maps to RUNX1. RUNX1 proteins are transcription factors that serve as scaffolds for the assembly of proteins that regulate transcription and RNA processing. After transfection, the RUNX1a, RUNX1b, and RUNX1-DeltaN variants allowed E4orf6-directed E1B-55K nuclear localization. The failure of RUNX1c to allow nuclear colocalization was relieved by the deletion of amino-terminal residues of this protein. In the adenovirus-infected mouse cell, RUNX1 proteins were localized to discrete structures about the periphery of viral replication centers. These sites are enriched in viral RNA and RNA-processing factors. RUNX1b and RUNX1a proteins displaced E4orf6 from these sites. The association of E1B-55K at viral replication centers was enhanced by the RUNX1a and RUNX1b proteins, but only in the absence of E4orf6. In the presence of E4orf6, E1B-55K occurred in a perinuclear cytoplasmic body resembling the aggresome and was excluded from the nucleus of the infected mouse cell. We interpret these findings to mean that a dynamic relationship exists between the E4orf6, E1B-55K, and RUNX1 proteins. In cooperation with E4orf6, RUNX1 proteins are able to modulate the localization of E1B-55K and even remodel virus-specific structures that form at late times of infection. Subsequent studies will need to determine a functional consequence of the interaction between E4orf6, E1B-55K, and RUNX1.
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35
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Osorio KM, Lee SE, McDermitt DJ, Waghmare SK, Zhang YV, Woo HN, Tumbar T. Runx1 modulates developmental, but not injury-driven, hair follicle stem cell activation. Development 2008; 135:1059-68. [PMID: 18256199 DOI: 10.1242/dev.012799] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Aml1/Runx1 controls developmental aspects of several tissues, is a master regulator of blood stem cells, and plays a role in leukemia. However, it is unclear whether it functions in tissue stem cells other than blood. Here, we have investigated the role of Runx1 in mouse hair follicle stem cells by conditional ablation in epithelial cells. Runx1 disruption affects hair follicle stem cell activation, but not their maintenance, proliferation or differentiation potential. Adult mutant mice exhibit impaired de novo production of hair shafts and all temporary hair cell lineages, owing to a prolonged quiescent phase of the first hair cycle. The lag of stem cell activity is reversed by skin injury. Our work suggests a degree of functional overlap in Runx1 regulation of blood and hair follicle stem cells at an equivalent time point in the development of these two tissues.
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Affiliation(s)
- Karen M Osorio
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14850, USA
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36
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Tsuzuki S, Hong D, Gupta R, Matsuo K, Seto M, Enver T. Isoform-specific potentiation of stem and progenitor cell engraftment by AML1/RUNX1. PLoS Med 2007; 4:e172. [PMID: 17503961 PMCID: PMC1868041 DOI: 10.1371/journal.pmed.0040172] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/26/2006] [Accepted: 03/19/2007] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND AML1/RUNX1 is the most frequently mutated gene in leukaemia and is central to the normal biology of hematopoietic stem and progenitor cells. However, the role of different AML1 isoforms within these primitive compartments is unclear. Here we investigate whether altering relative expression of AML1 isoforms impacts the balance between cell self-renewal and differentiation in vitro and in vivo. METHODS AND FINDINGS The human AML1a isoform encodes a truncated molecule with DNA-binding but no transactivation capacity. We used a retrovirus-based approach to transduce AML1a into primitive haematopoietic cells isolated from the mouse. We observed that enforced AML1a expression increased the competitive engraftment potential of murine long-term reconstituting stem cells with the proportion of AML1a-expressing cells increasing over time in both primary and secondary recipients. Furthermore, AML1a expression dramatically increased primitive and committed progenitor activity in engrafted animals as assessed by long-term culture, cobblestone formation, and colony assays. In contrast, expression of the full-length isoform AML1b abrogated engraftment potential. In vitro, AML1b promoted differentiation while AML1a promoted proliferation of progenitors capable of short-term lymphomyeloid engraftment. Consistent with these findings, the relative abundance of AML1a was highest in the primitive stem/progenitor compartment of human cord blood, and forced expression of AML1a in these cells enhanced maintenance of primitive potential both in vitro and in vivo. CONCLUSIONS These data demonstrate that the "a" isoform of AML1 has the capacity to potentiate stem and progenitor cell engraftment, both of which are required for successful clinical transplantation. This activity is consistent with its expression pattern in both normal and leukaemic cells. Manipulating the balance of AML1 isoform expression may offer novel therapeutic strategies, exploitable in the contexts of leukaemia and also in cord blood transplantation in adults, in whom stem and progenitor cell numbers are often limiting.
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Affiliation(s)
- Shinobu Tsuzuki
- Division of Molecular Medicine, Aichi Cancer Center Research Institute, Nagoya, Japan.
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37
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Peterson LF, Boyapati A, Ahn EY, Biggs JR, Okumura AJ, Lo MC, Yan M, Zhang DE. Acute myeloid leukemia with the 8q22;21q22 translocation: secondary mutational events and alternative t(8;21) transcripts. Blood 2007; 110:799-805. [PMID: 17412887 PMCID: PMC1924771 DOI: 10.1182/blood-2006-11-019265] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Nonrandom and somatically acquired chromosomal translocations can be identified in nearly 50% of human acute myeloid leukemias. One common chromosomal translocation in this disease is the 8q22;21q22 translocation. It involves the AML1 (RUNX1) gene on chromosome 21 and the ETO (MTG8, RUNX1T1) gene on chromosome 8 generating the AML1-ETO fusion proteins. In this review, we survey recent advances made involving secondary mutational events and alternative t(8;21) transcripts in relation to understanding AML1-ETO leukemogenesis.
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MESH Headings
- Animals
- Cell Transformation, Neoplastic/genetics
- Cell Transformation, Neoplastic/metabolism
- Chromosomes, Human, Pair 21/genetics
- Chromosomes, Human, Pair 21/metabolism
- Chromosomes, Human, Pair 8/genetics
- Chromosomes, Human, Pair 8/metabolism
- Core Binding Factor Alpha 2 Subunit/biosynthesis
- Core Binding Factor Alpha 2 Subunit/genetics
- Humans
- Leukemia, Myeloid, Acute/genetics
- Leukemia, Myeloid, Acute/metabolism
- Leukemia, Myeloid, Acute/pathology
- Mice
- Oncogene Proteins, Fusion/biosynthesis
- Oncogene Proteins, Fusion/genetics
- RUNX1 Translocation Partner 1 Protein
- Transcription, Genetic
- Translocation, Genetic
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Affiliation(s)
- Luke F Peterson
- Department of Molecular and Experimental Medicine, Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
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Abe M, Sato Y. Puromycin insensitive leucyl-specific aminopeptidase (PILSAP) is required for the development of vascular as well as hematopoietic system in embryoid bodies. Genes Cells 2006; 11:719-29. [PMID: 16824192 DOI: 10.1111/j.1365-2443.2006.00978.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
We have shown that puromycin insensitive leucyl-specific aminopeptidase (PILSAP) is required for regulation of angiogenesis. However, it remains unclear whether PILSAP plays a role in endothelial cell (EC) differentiation. We examined the role of PILSAP by using an embryoid bodies (EBs) culture system. Fms-like tyrosine kinase-1 (Flk-1) showed two expression peaks on days 4 and 10 of culture. These two peaks represent populations of mesodermal precursors and mature ECs, respectively. Endothelial markers such as VE-cadherin, CD34, CD31 and Tie2 followed the first peak of Flk-1. Interestingly, the expression of PILSAP showed a pattern similar to that of Flk-1. ES cells transfected with mutant PILSAP (mtPILSAP) cDNA of a dominant negative activity organized less vascular structure and showed decreased levels of vascular lineage markers. The similar results were obtained in EBs treated with leucinethiol, a specific inhibitor of leucine aminopeptidase or siRNA for PILSAP. However, Flk-1 expression was unaffected on day 4. The expression of markers for hematopoietic lineage and muscle cells in mtPILSAP-EBs was also reduced. These results suggest that although PILSAP may not function in the initial generation of Flk-1 positive mesodermal precursors, it dose play a role in growth of vascular, hematopoietic, and muscular lineage population from those precursors.
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Affiliation(s)
- Mayumi Abe
- Department of Vascular Biology, Institute of Development, Aging and Cancer, Tohoku University, 4-1 Seiryo-machi, Aoba-ku, Sendai, 980-8575, Japan.
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39
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Saltman LH, Javed A, Ribadeneyra J, Hussain S, Young DW, Osdoby P, Amcheslavsky A, van Wijnen AJ, Stein JL, Stein GS, Lian JB, Bar-Shavit Z. Organization of transcriptional regulatory machinery in osteoclast nuclei: compartmentalization of Runx1. J Cell Physiol 2005; 204:871-80. [PMID: 15828028 DOI: 10.1002/jcp.20329] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The osteoclast is a highly polarized multinucleated cell that resorbs bone. Using high resolution immunofluorescence microscopy, we demonstrated that all nuclei of an osteoclast are transcriptionally active. Each nucleus within the osteoclast contains punctately organized microenvironments where regulatory complexes that support transcriptional and post-transcriptional control reside. Functional equivalency of osteoclast nuclei is reflected by similar representation of regulatory proteins that support ribosomal RNA synthesis (nucleolin), mRNA transcription (RNA polymerase II, bromouridine triphosphate), processing of gene transcripts (SC35), signal transduction (NF-kappaB), and phenotypic gene expression (Runx1). Our results establish that gene regulatory machinery is architecturally associated and compartmentalized within intranuclear microenvironments of the multiple nuclei of osteoclasts to support physiologically responsive modifications in cellular structural and functional properties.
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Affiliation(s)
- Laura H Saltman
- Department of Cell Biology, University of Massachusetts Medical School, Worcester, 01655, USA
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40
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Burns CE, Traver D, Mayhall E, Shepard JL, Zon LI. Hematopoietic stem cell fate is established by the Notch-Runx pathway. Genes Dev 2005; 19:2331-42. [PMID: 16166372 PMCID: PMC1240042 DOI: 10.1101/gad.1337005] [Citation(s) in RCA: 317] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Identifying the molecular pathways regulating hematopoietic stem cell (HSC) specification, self-renewal, and expansion remains a fundamental goal of both basic and clinical biology. Here, we analyzed the effects of Notch signaling on HSC number during zebrafish development and adulthood, defining a critical pathway for stem cell specification. The Notch signaling mutant mind bomb displays normal embryonic hematopoiesis but fails to specify adult HSCs. Surprisingly, transient Notch activation during embryogenesis via an inducible transgenic system led to a Runx1-dependent expansion of HSCs in the aorta-gonad-mesonephros (AGM) region. In irradiated adults, Notch activity induced runx1 gene expression and increased multilineage hematopoietic precursor cells approximately threefold in the marrow. This increase was followed by the accelerated recovery of all the mature blood cell lineages. These data define the Notch-Runx pathway as critical for the developmental specification of HSC fate and the subsequent homeostasis of HSC number, thus providing a mechanism for amplifying stem cells in vivo.
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Affiliation(s)
- Caroline Erter Burns
- Stem Cell Program and Division of Hematology/Oncology Children's Hospital and Dana Farber Cancer Institute, Howard Hughes Medical Institute, Harvard Stem Cell Institute, Harvard Medical School, Boston, Massachusetts 02115, USA
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41
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Zambidis ET, Peault B, Park TS, Bunz F, Civin CI. Hematopoietic differentiation of human embryonic stem cells progresses through sequential hematoendothelial, primitive, and definitive stages resembling human yolk sac development. Blood 2005; 106:860-70. [PMID: 15831705 PMCID: PMC1895146 DOI: 10.1182/blood-2004-11-4522] [Citation(s) in RCA: 291] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2004] [Accepted: 04/03/2005] [Indexed: 12/17/2022] Open
Abstract
We elucidate the cellular and molecular kinetics of the stepwise differentiation of human embryonic stem cells (hESCs) to primitive and definitive erythromyelopoiesis from human embryoid bodies (hEBs) in serum-free clonogenic assays. Hematopoiesis initiates from CD45 hEB cells with emergence of semiadherent mesodermal-hematoendothelial (MHE) colonies that can generate endothelium and form organized, yolk sac-like structures that secondarily generate multipotent primitive hematopoietic stem progenitor cells (HSPCs), erythroblasts, and CD13+CD45+ macrophages. A first wave of hematopoiesis follows MHE colony emergence and is predominated by primitive erythropoiesis characterized by a brilliant red hemoglobinization, CD71/CD325a (glycophorin A) expression, and exclusively embryonic/fetal hemoglobin expression. A second wave of definitive-type erythroid burst-forming units (BFU-e's), erythroid colony-forming units (CFU-e's), granulocyte-macrophage colony-forming cells (GM-CFCs), and multilineage CFCs follows next from hEB progenitors. These stages of hematopoiesis proceed spontaneously from hEB-derived cells without requirement for supplemental growth factors during hEB differentiation. Gene expression analysis of differentiating hEBs revealed that initiation of hematopoiesis correlated with increased levels of SCL/TAL1, GATA1, GATA2, CD34, CD31, and the homeobox gene-regulating factor CDX4 These data indicate that hematopoietic differentiation of hESCs models the earliest events of embryonic and definitive hematopoiesis in a manner resembling human yolk sac development, thus providing a valuable tool for dissecting the earliest events in human HSPC genesis.
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Affiliation(s)
- Elias T Zambidis
- Division of Immunology and Hematopoiesis, Sidney Kimmel comprehensive Cancer Center at John Hokins, The John Hopkins School of Medicine, Baltimore, MD, USA.
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42
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Hirai H, Samokhvalov IM, Fujimoto T, Nishikawa S, Imanishi J, Nishikawa SI. Involvement of Runx1 in the down-regulation of fetal liver kinase-1 expression during transition of endothelial cells to hematopoietic cells. Blood 2005; 106:1948-55. [PMID: 15928041 DOI: 10.1182/blood-2004-12-4872] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
During early mouse embryogenesis, fetal liver kinase-1 (Flk-1), a receptor for vascular endothelial growth factor, and Runx1, a runt domain transcription factor, have prerequisite roles in the generation of hematopoietic lineages. Flk-1 expression is maintained in successive stages from mesodermal to endothelial cells and is down-regulated in nascent hematopoietic cells, whereas Runx1 (Runt-related transcription factor 1) is expressed in embryonic sites of hematopoietic cell de novo generation and in practically all hematopoietic organs. Here we show that Runx1 represses Flk-1 during the development of hemogenic endothelial cells into hematopoietic cells. We established embryonic stem cell clones carrying the Venus gene, a modified version of yellow fluorescence protein, in the Runx1 locus and cultured them on OP9 cells. Flk-1+ cells appeared on day 3.5, and Runx1+ cells first appeared from the Flk-1+ fraction on day 4.5. The Flk-1+Runx1+ cells rapidly stopped expressing Flk-1 with further incubation and eventually gave rise to CD45+ or TER119+ cells. Runx1 repressed Flk-1 promoter transcriptional activity in an endothelial cell line, and this repression required intact DNA-binding and transactivating domains of Runx1 protein. The repressor activity of Runx1 endogenous Flk-1 was also confirmed overexpressing Runx1 in embryonic stem cell differentiation cultures. These results provide novel insight into the role Runx1 during the development of hematopoietic cell lineages.
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Affiliation(s)
- Hideyo Hirai
- Department of Microbiology, Kyoto Prefectural University of Medicine, Kamigyo-ku, Kyoto 602-8566, Japan.
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43
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Fukushima-Nakase Y, Naoe Y, Taniuchi I, Hosoi H, Sugimoto T, Okuda T. Shared and distinct roles mediated through C-terminal subdomains of acute myeloid leukemia/Runt-related transcription factor molecules in murine development. Blood 2005; 105:4298-307. [PMID: 15713794 DOI: 10.1182/blood-2004-08-3372] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
AML1/Runx1 is a frequent target of human leukemia-associated gene aberration and encodes a transcription factor with nonredundant biologic functions in initial development of definitive hematopoiesis, T-cell development, and steady-state platelet production. AML1/Runx1 and 2 closely related family genes, AML2/Runx3 and AML3/Runx2/Cbfa1, present in mammals, comprise the Runt-domain transcription factor family. Although they have similar structural and biochemical properties, gene-targeting experiments have identified distinct biologic roles. To directly determine the presence of functional overlap among runt-related transcription factor (Runx) family molecules, we replaced the C-terminal portion of acute myeloid leukemia 1 (AML1) with that derived from its family members, which are variable in contrast to conserved Runt domain, using the gene knock-in method. We found that C-terminal portions of either AML2 or AML3 could functionally replace that of AML1 for myeloid development in culture and within the entire mouse. However, while AML2 substituted for AML1 could effectively rescue lymphoid lineages, AML3 could not, resulting in a smaller thymus and lymphoid deficiency in peripheral blood. Substitution by the C-terminal portion of AML3 also led to high infantile mortality and growth retardation, suggesting that AML1 has as yet unidentified effects on these phenotypes. Thus, the C-terminal portions of Runx family members have both similar and distinct biologic functions.
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Affiliation(s)
- Yoko Fukushima-Nakase
- Department of Molecular-Targeting Cancer Prevention, Kyoto Prefectural University of Medicine, Graduate School of Medical Science, Kawaramachi-Hirokoji, Kamigyo-ku, Kyoto 602-8566, Japan
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44
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Nakao M, Horiike S, Fukushima-Nakase Y, Nishimura M, Fujita Y, Taniwaki M, Okuda T. Novel loss-of-function mutations of the haematopoiesis-related transcription factor, acute myeloid leukaemia 1/runt-related transcription factor 1, detected in acute myeloblastic leukaemia and myelodysplastic syndrome. Br J Haematol 2004; 125:709-19. [PMID: 15180860 DOI: 10.1111/j.1365-2141.2004.04966.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
AML1/RUNX1, which encodes a transcription factor essential for definitive haematopoiesis, is a frequent target of leukaemia-associated chromosome translocations. Point mutations of this gene have also recently been associated with leukaemia and myelodysplastic syndrome (MDS). To further define the frequency and biological characteristics of AML1 mutations, we have examined 170 cases of such diseases. Mutations within the runt-domain were identified in five cases: one of de novo acute myeloid leukaemia (AML) and four of MDS. Where multiple time point samples were available, mutations were detected in the earliest samples, which persisted throughout the disease course. Of the five mutations, one was a silent mutation, two were apparent loss-of-function mutations caused by N-terminal truncation, and two were insertions, I150ins and K168ins, which preserved most of the AML1 DNA-binding domain. Both AML1 molecules with insertion mutations were non-functional in that they were unable to rescue haematological defects in AML1-deficient mouse embryonic stem cells. In addition, activating mutations of N-ras, deletion of chromosome 12p, or inactivation of TP53 accompanied some of the AML1 mutations. Together, these observations strongly suggest that one-allele inactivation of AML1 serves as an initial or early event that plays an important role in the eventual development of overt diseases with additional genetic alterations.
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Affiliation(s)
- Mitsushige Nakao
- Molecular-Targeting Cancer Prevention, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kawaramach-Hirokoji, Kamigyo-ku, Kyoto, Japan
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45
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Baumert U, Golan I, Becker B, Hrala BP, Redlich M, Roos HA, Palmon A, Reichenberg E, Müssig D. Pressure simulation of orthodontic force in osteoblasts: a pilot study. Orthod Craniofac Res 2004; 7:3-9. [PMID: 14989748 DOI: 10.1046/j.1601-6335.2003.00270.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVES To elucidate the RUNX2 gene expression induction in human osteoblasts after mechanical loading. DESIGN Using a stringent pulse-chase protocol human osteoblasts were exposed to centrifugal pressure force for 30 and 90 min. Untreated control cells were processed in parallel. Before, and at defined times after centrifugation, total RNA was isolated. RUNX2 gene expression was measured using real-time quantitative reverse transcriptase polymerase chain reaction. The stress/control ratio was used to illustrate possible stimulatory or diminishing effects of force application. RESULTS Immediately after 30 min of force application the RUNX2 gene expression was induced by a factor of 1.7 +/- 0.14 as compared with the negative control. This induction decreased rapidly and reached its pre-load levels within 30 min. Longer force applications (up to 90 min) did not change the RUNX2 gene expression. CONCLUSION In mature osteoblasts centrifugal pressure force stimulates RUNX2 gene expression within a narrow time frame: loading of mature cells results in a temporary increase of RUNX2 expression and a fast downregulation back to its pre-load expression level. With this pilot study the gene expression behavior after mechanical stimuli could be determined with a simple laboratory setup.
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Affiliation(s)
- U Baumert
- Department of Orthodontics, Center for Craniofacial Genetics, University of Regensburg, Germany.
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46
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Lacaud G, Kouskoff V, Trumble A, Schwantz S, Keller G. Haploinsufficiency of Runx1 results in the acceleration of mesodermal development and hemangioblast specification upon in vitro differentiation of ES cells. Blood 2004; 103:886-9. [PMID: 14525762 DOI: 10.1182/blood-2003-06-2149] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
AbstractThe AML1 gene (recently renamed Runx1), which encodes the DNA-binding subunit of a transcription factor of the core binding factor (CBF) family, is required for the establishment of definitive hematopoiesis. We have previously demonstrated that Runx1 is expressed in yolk sac mesodermal cells prior to the establishment of the blood islands and in the embryoid body (EB)–derived blast-colony–forming cells (BL-CFCs), the in vitro equivalent of the hemangioblast. Analysis of Runx1-deficient embryonic stem (ES) cells demonstrated that this gene is essential for the generation of normal numbers of blast colonies, the progeny of the BL-CFCs. In the present study, we analyzed the potential of Runx1+/– ES cells to determine if heterozygosity at the Runx1 locus impacts early developmental events leading to the commitment of the BL-CFCs. Our results indicate that Runx1 heterozygosity leads to an acceleration of mesodermal commitment and specification to the BL-CFCs and to the hematopoietic lineages in EBs.
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Affiliation(s)
- Georges Lacaud
- Carl C. Icahn Center for Gene Therapy and Molecular Medicine, Mount Sinai School of Medicine, New York, NY 10029, USA
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47
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Nishimura M, Fukushima-Nakase Y, Fujita Y, Nakao M, Toda S, Kitamura N, Abe T, Okuda T. VWRPY motif-dependent and -independent roles of AML1/Runx1 transcription factor in murine hematopoietic development. Blood 2003; 103:562-70. [PMID: 14504086 DOI: 10.1182/blood-2003-06-2109] [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: 11/20/2022] Open
Abstract
AML1/Runx1 is a frequent target of leukemia-associated gene aberration, and it encodes a transcription factor essential for definitive hematopoiesis. We previously reported that the AML1 molecules with trans-activation subdomains retained can rescue in vitro hematopoietic defects of AML1-deficient mouse embryonic stem (ES) cells when expressed by using a knock-in approach. Extending this notion to in vivo conditions, we found that the knock-in ES cell clones with AML1 mutants, which retain trans-activation subdomains but lack C-terminal repression subdomains including the conserved VWRPY motif, contribute to hematopoietic tissues in chimera mice. We also found that germline mice homozygous for the mutated AML1 allele, which lacks the VWRPY motif, exhibit a minimal effect on hematopoietic development, as was observed in control knock-in mice with full-length AML1. On the other hand, reduced cell numbers and deviant CD4 expression were observed during early T-lymphoid ontogeny in the VWRPY-deficient mice, whereas the contribution to the thymus by the corresponding ES cell clones was inadequate. These findings demonstrate that AML1 with its trans-activating subdomains is essential and sufficient for hematopoietic development in the context of the entire mouse. In addition, its trans-repression activity, depending on the C-terminal VWRPY motif, plays a role in early thymocyte development.
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Affiliation(s)
- Motohiro Nishimura
- Department of Hygiene, Kyoto Prefectural University of Medicine, Kawaramachi-Hirokoji, Kamigyo-ku, Kyoto 602-8566, Japan
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Burns CE, DeBlasio T, Zhou Y, Zhang J, Zon L, Nimer SD. Isolation and characterization of runxa and runxb, zebrafish members of the runt family of transcriptional regulators. Exp Hematol 2002; 30:1381-9. [PMID: 12482499 DOI: 10.1016/s0301-472x(02)00955-4] [Citation(s) in RCA: 98] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
OBJECTIVE The AML/RUNX family of transcription factors plays important roles in hematopoiesis, neurogenesis, bone development, and segmentation in vertebrate embryos. The aim of this study was to isolate runt-related genes in a genetically and embryologically exploitable system, the zebrafish, and characterize their function during hematopoietic development. MATERIALS AND METHODS Two runt-related genes were isolated by degenerate PCR and standard library screening, and a radiation hybrid panel, T51 RH, was used to resolve their chromosomal localization. In situ hybridization demonstrated their expression whereas their transcriptional activity was assessed using an AML1-responsive reporter gene in the MLA 144 T-cell line. RESULTS We isolated the zebrafish runxa and runxb cDNAs, which encode proteins highly homologous to the human and murine Runx1 (AML1) and Runx3 (AML2) proteins. In contrast to a recent report, we detected runxa expression in both hematopoietic and neural tissues of the developing zebrafish. runxa transcripts first appear during segmentation in bilateral mesodermal cells that coexpress one of the earliest blood and endothelial cell markers, scl/tal-1. By 24 hours postfertilization (hpf), runxa transcripts are seen in the ventral wall of the dorsal aorta. Hematopoietic runxa expression is lost in cloche mutants, which are defective in blood and endothelial cell formation. runxb transcripts are seen in nonhematopoietic domains. Both Runxa and Runxb transactivate an AML1-responsive human promoter in hematopoietic cells. Genomic localization studies demonstrate that runxa is located on linkage group 1 (LG1), and the runxb gene is located on LG13. CONCLUSIONS Our gene expression analysis strongly suggests that both the functional and spatial aorta-gonad-mesonephros (AGM) region has been conserved throughout evolution. Our runxa spatiotemporal expression data shed light on the role of vertebrate Runx1/AML1 in primitive vs definitive hematopoietic development.
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MESH Headings
- Amino Acid Sequence
- Animals
- Aorta/embryology
- Core Binding Factor Alpha 2 Subunit
- Core Binding Factor Alpha 3 Subunit
- DNA, Complementary/genetics
- DNA, Complementary/isolation & purification
- DNA-Binding Proteins/genetics
- Embryo, Nonmammalian
- Endothelium, Vascular/chemistry
- Endothelium, Vascular/cytology
- Endothelium, Vascular/embryology
- Gene Expression Regulation, Developmental
- Genetic Linkage
- Gonads/embryology
- Hematopoiesis/genetics
- Humans
- Mesonephros/embryology
- Molecular Sequence Data
- Phylogeny
- Promoter Regions, Genetic/drug effects
- Proto-Oncogene Proteins
- RNA, Messenger/analysis
- Sequence Homology, Amino Acid
- Transcription Factors/genetics
- Transcription Factors/isolation & purification
- Transcription Factors/pharmacology
- Zebrafish
- Zebrafish Proteins/genetics
- Zebrafish Proteins/isolation & purification
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Abstract
It has been well established that a number of transcription factors play critical roles in regulating the fate of hematopoietic stem cell populations. One of them is the leukemia-associated transcription factor acute myeloid leukemia 1 (AML1; also known as runt-related transcription factor 1, or RUNX1). This gene was originally cloned from the breakpoint of the t(8;21) reciprocal chromosome translocation and was later recognized as one of the most frequent targets of leukemia-associated gene aberrations. Gene-targeting experiments revealed that transcriptionally active AML1 is essential for the establishment of definitive hematopoiesis. More specifically, this gene functions in the emergence of the hematopoietic progenitor cells from the hemogenic endothelium by budding in the aorta-gonad-mesonephros region, and its expression points to the sites with strong potential for the emergence of hematopoietic stem cells. This review discusses aspects of the biologic properties of AML1 in early hematopoietic development.
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Affiliation(s)
- T Okuda
- Departments of Hygiene, Kyoto Prefectural University of Medicine, Japan.
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