1
|
Qiu K, Vu D, Wang L, Bookstaver A, Dinh TN, Goldfarb AN, Tenen DG, Trinh BQ. Chromatin structure and 3D architecture define differential functions of PU.1 cis regulatory elements in human blood cell lineages. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.01.573782. [PMID: 38260486 PMCID: PMC10802337 DOI: 10.1101/2024.01.01.573782] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
The precise spatio-temporal expression of the hematopoietic ETS transcription factor PU.1 that determines the hematopoietic cell fates is tightly regulated at the chromatin level. However, it remains elusive as to how chromatin signatures are linked to this dynamic expression pattern of PU.1 across blood cell lineages. Here we performed an unbiased and in-depth analysis of the relationship between human PU.1 expression, the presence of trans-acting factors, and 3D architecture at various cis-regulatory elements (CRE) proximal to the PU.1 locus. We identified multiple novel CREs at the upstream region of the gene following an integrative inspection for conserved DNA elements at the chromatin-accessible regions in primary human blood lineages. We showed that a subset of CREs localize within a 10 kb-wide cluster that exhibits that exhibit molecular features of a myeloid-specific super-enhancer involved in mediating PU.1 autoregulation, including open chromatin, unmethylated DNA, histone enhancer marks, transcription of enhancer RNAs, and occupancy of the PU.1 protein itself. Importantly, we revealed the presence of common 35-kb-wide CTCF-bound insulated neighborhood that contains the CRE cluster, forming the chromatin territory for lineage-specific and CRE-mediated chromatin interactions. These include functional CRE-promoter interactions in myeloid and B cells but not in erythroid and T cells. Our findings also provide mechanistic insights into the interplay between dynamic chromatin structure and 3D architecture in defining certain CREs as enhancers or silencers in chromatin regulation of PU.1 expression. The study lays the groundwork for further examination of PU.1 CREs as well as epigenetic regulation in malignant hematopoiesis.
Collapse
|
2
|
Jones R, Hill M, Taylor P. Spi1 -14 Kb upstream regulatory element (URE) is not required for maintenance of PU.1 expression in macrophages. Wellcome Open Res 2022. [DOI: 10.12688/wellcomeopenres.17705.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Background: Previous work suggested an upstream regulatory element (URE) of Spi1 was required to maintain constant expression of the PU.1 transcription factor in bone marrow and foetal liver cells. PU.1, encoded by Spi1, is essential for development and maintenance of myeloid and B-lymphocyte populations in mice. Deletion of this (-14 Kb) URE potentially reduces expression of PU.1 and therefore provides a way to investigate its role in myeloid populations in development and disease. This study aimed to examine the impact of removal of the -14 Kb Spi1 URE in Cx3cr1+ cells on the myeloid lineage formation and maintenance. Methods: B6;129-Spi1tm1.2Dgt/J mice, whose -14 Kb Spi1 URE mice is flanked by LoxP sites (‘floxed’), were bred to a strain with constitutively active Cre expressed under the Cx3cr1 promoter (B6J.B6N(Cg)-Cx3cr1tm1.1(cre)Jung/J) to delete the Spi1 URE in myeloid cells. The floxed mice were also bred to mice with a tamoxifen-inducible Cre expressed under the Cx3cr1 promoter (B6.129P2(C)-Cx3cr1tm2.1(cre/ERT2)Jung/J) to be used as URE intact controls and to permit temporally-controlled deletion of the URE if required. PU.1 protein expression was measured in the peritoneal macrophages and microglia by flow cytometry. Additionally, a Cre-encoding lentiviral vector was used to assess the impact on PU.1 expression in bone-marrow derived macrophages from these mice in vitro. Results: Expression of the PU.1 transcription factor was not significantly altered in the peritoneal macrophages or microglia in mice lacking the -14 Kb Spi1 URE. Moreover, initial experiments utilising Cre encoding lentivirus did not reduce PU.1 protein in bone-marrow derived macrophages differentiated from the -14 Kb Spi1 URE floxed mice. Conclusions: These observations suggest that the -14 Kb URE does not play a major role in PU.1 protein expression in either mature peritoneal macrophages or microglia.
Collapse
|
3
|
Ahmed N, Etzrodt M, Dettinger P, Kull T, Loeffler D, Hoppe PS, Chavez JS, Zhang Y, Camargo Ortega G, Hilsenbeck O, Nakajima H, Pietras EM, Schroeder T. Blood stem cell PU.1 upregulation is a consequence of differentiation without fast autoregulation. J Exp Med 2022; 219:e20202490. [PMID: 34817548 PMCID: PMC8624737 DOI: 10.1084/jem.20202490] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Revised: 05/07/2021] [Accepted: 09/23/2021] [Indexed: 11/12/2022] Open
Abstract
Transcription factors (TFs) regulate cell fates, and their expression must be tightly regulated. Autoregulation is assumed to regulate many TFs' own expression to control cell fates. Here, we manipulate and quantify the (auto)regulation of PU.1, a TF controlling hematopoietic stem and progenitor cells (HSPCs), and correlate it to their future fates. We generate transgenic mice allowing both inducible activation of PU.1 and noninvasive quantification of endogenous PU.1 protein expression. The quantified HSPC PU.1 dynamics show that PU.1 up-regulation occurs as a consequence of hematopoietic differentiation independently of direct fast autoregulation. In contrast, inflammatory signaling induces fast PU.1 up-regulation, which does not require PU.1 expression or its binding to its own autoregulatory enhancer. However, the increased PU.1 levels induced by inflammatory signaling cannot be sustained via autoregulation after removal of the signaling stimulus. We conclude that PU.1 overexpression induces HSC differentiation before PU.1 up-regulation, only later generating cell types with intrinsically higher PU.1.
Collapse
Affiliation(s)
- Nouraiz Ahmed
- Department of Biosystems Science & Engineering, Eidgenössische Technische Hochschule Zürich, Basel, Switzerland
| | - Martin Etzrodt
- Department of Biosystems Science & Engineering, Eidgenössische Technische Hochschule Zürich, Basel, Switzerland
| | - Philip Dettinger
- Department of Biosystems Science & Engineering, Eidgenössische Technische Hochschule Zürich, Basel, Switzerland
| | - Tobias Kull
- Department of Biosystems Science & Engineering, Eidgenössische Technische Hochschule Zürich, Basel, Switzerland
| | - Dirk Loeffler
- Department of Biosystems Science & Engineering, Eidgenössische Technische Hochschule Zürich, Basel, Switzerland
| | - Philipp S. Hoppe
- Department of Biosystems Science & Engineering, Eidgenössische Technische Hochschule Zürich, Basel, Switzerland
| | - James S. Chavez
- Division of Hematology, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO
| | - Yang Zhang
- Department of Biosystems Science & Engineering, Eidgenössische Technische Hochschule Zürich, Basel, Switzerland
| | - Germán Camargo Ortega
- Department of Biosystems Science & Engineering, Eidgenössische Technische Hochschule Zürich, Basel, Switzerland
| | - Oliver Hilsenbeck
- Department of Biosystems Science & Engineering, Eidgenössische Technische Hochschule Zürich, Basel, Switzerland
| | - Hideaki Nakajima
- Department of Stem Cell and Immune Regulation, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Eric M. Pietras
- Division of Hematology, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO
| | - Timm Schroeder
- Department of Biosystems Science & Engineering, Eidgenössische Technische Hochschule Zürich, Basel, Switzerland
| |
Collapse
|
4
|
Wang M, Wang J, Zhang X, Yuan R. The complex landscape of haematopoietic lineage commitments is encoded in the coarse-grained endogenous network. ROYAL SOCIETY OPEN SCIENCE 2021; 8:211289. [PMID: 34737882 PMCID: PMC8564612 DOI: 10.1098/rsos.211289] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2021] [Accepted: 09/29/2021] [Indexed: 05/15/2023]
Abstract
Haematopoietic lineage commitments are presented by a canonical roadmap in which haematopoietic stem cells or multipotent progenitors (MPPs) bifurcate into progenitors of more restricted lineages and ultimately mature to terminally differentiated cells. Although transcription factors playing significant roles in cell-fate commitments have been extensively studied, integrating such knowledge into the dynamic models to understand the underlying biological mechanism remains challenging. The hypothesis and modelling approach of the endogenous network has been developed previously and tested in various biological processes and is used in the present study of haematopoietic lineage commitments. The endogenous network is constructed based on the key transcription factors and their interactions that determine haematopoietic cell-fate decisions at each lineage branchpoint. We demonstrate that the process of haematopoietic lineage commitments can be reproduced from the landscape which orchestrates robust states of network dynamics and their transitions. Furthermore, some non-trivial characteristics are unveiled in the dynamical model. Our model also predicted previously under-represented regulatory interactions and heterogeneous MPP states by which distinct differentiation routes are intermediated. Moreover, network perturbations resulting in state transitions indicate the effects of ectopic gene expression on cellular reprogrammes. This study provides a predictive model to integrate experimental data and uncover the possible regulatory mechanism of haematopoietic lineage commitments.
Collapse
Affiliation(s)
- Mengyao Wang
- School of Life Science, Shanghai University, Shanghai 200444, People's Republic of China
- Shanghai Center for Quantitative Life Sciences and Physics Department, Shanghai University, Shanghai 200444, People's Republic of China
| | - Junqiang Wang
- Key Laboratory of Systems Biomedicine, Shanghai Center for Systems Biomedicine, Shanghai Jiao Tong University, Shanghai 200240, People's Republic of China
| | - Xingxing Zhang
- Shanghai Center for Quantitative Life Sciences and Physics Department, Shanghai University, Shanghai 200444, People's Republic of China
| | - Ruoshi Yuan
- California Institute for Quantitative Biosciences (QB3), University of California, Berkeley, CA 94706, USA
| |
Collapse
|
5
|
Hosokawa H, Koizumi M, Masuhara K, Romero-Wolf M, Tanaka T, Nakayama T, Rothenberg EV. Stage-specific action of Runx1 and GATA3 controls silencing of PU.1 expression in mouse pro-T cells. J Exp Med 2021; 218:e20202648. [PMID: 34180951 PMCID: PMC8241539 DOI: 10.1084/jem.20202648] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Revised: 05/01/2021] [Accepted: 06/10/2021] [Indexed: 12/16/2022] Open
Abstract
PU.1 (encoded by Spi1), an ETS-family transcription factor with many hematopoietic roles, is highly expressed in the earliest intrathymic T cell progenitors but must be down-regulated during T lineage commitment. The transcription factors Runx1 and GATA3 have been implicated in this Spi1 repression, but the basis of the timing was unknown. We show that increasing Runx1 and/or GATA3 down-regulates Spi1 expression in pro-T cells, while deletion of these factors after Spi1 down-regulation reactivates its expression. Leveraging the stage specificities of repression and transcription factor binding revealed an unconventional but functional site in Spi1 intron 2. Acute Cas9-mediated deletion or disruption of the Runx and GATA motifs in this element reactivates silenced Spi1 expression in a pro-T cell line, substantially more than disruption of other candidate elements, and counteracts the repression of Spi1 in primary pro-T cells during commitment. Thus, Runx1 and GATA3 work stage specifically through an intronic silencing element in mouse Spi1 to control strength and maintenance of Spi1 repression during T lineage commitment.
Collapse
Affiliation(s)
- Hiroyuki Hosokawa
- Department of Immunology, Tokai University School of Medicine, Isehara, Kanagawa, Japan
- Institute of Medical Sciences, Tokai University, Isehara, Kanagawa, Japan
- Division of Biology & Biological Engineering, California Institute of Technology, Pasadena, CA
| | - Maria Koizumi
- Department of Immunology, Tokai University School of Medicine, Isehara, Kanagawa, Japan
| | - Kaori Masuhara
- Department of Immunology, Tokai University School of Medicine, Isehara, Kanagawa, Japan
| | - Maile Romero-Wolf
- Division of Biology & Biological Engineering, California Institute of Technology, Pasadena, CA
| | - Tomoaki Tanaka
- Department of Molecular Diagnosis, Graduate School of Medicine, Chiba University, Chuo-ku, Chiba, Japan
| | - Toshinori Nakayama
- Department of Immunology, Graduate School of Medicine, Chiba University, Chuo-ku, Chiba, Japan
| | - Ellen V Rothenberg
- Division of Biology & Biological Engineering, California Institute of Technology, Pasadena, CA
| |
Collapse
|
6
|
Jones RE, Andrews R, Holmans P, Hill M, Taylor PR. Modest changes in Spi1 dosage reveal the potential for altered microglial function as seen in Alzheimer's disease. Sci Rep 2021; 11:14935. [PMID: 34294785 PMCID: PMC8298495 DOI: 10.1038/s41598-021-94324-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Accepted: 07/07/2021] [Indexed: 12/12/2022] Open
Abstract
Genetic association studies have identified multiple variants at the SPI1 locus that modify risk and age of onset for Alzheimer's Disease (AD). Reports linking risk variants to gene expression suggest that variants denoting higher SPI1 expression are likely to have an earlier AD onset, and several other AD risk genes contain PU.1 binding sites in the promoter region. Overall, this suggests the level of SPI1 may alter microglial phenotype potentially impacting AD. This study determined how the microglial transcriptome was altered following modest changes to Spi1 expression in primary mouse microglia. RNA-sequencing was performed on microglia with reduced or increased Spi1/PU.1 expression to provide an unbiased approach to determine transcriptomic changes affected by Spi1. In summary, a reduction in microglial Spi1 resulted in the dysregulation of transcripts encoding proteins involved in DNA replication pathways while an increased Spi1 results in an upregulation of genes associated with immune response pathways. Additionally, a subset of 194 Spi1 dose-sensitive genes was identified and pathway analysis suggests that several innate immune and interferon response pathways are impacted by the concentration of Spi1. Together these results suggest Spi1 levels can alter the microglial transcriptome and suggests interferon pathways may be altered in individuals with AD related Spi1 risk SNPs.
Collapse
Affiliation(s)
- Ruth E Jones
- Division of Infection and Immunity, Cardiff University, Cardiff, UK
- UK Dementia Research Institute at Cardiff, Cardiff University, Hadyn Ellis Building, Maindy Road, Cardiff, CF24 4HQ, UK
| | - Robert Andrews
- Division of Infection and Immunity, Cardiff University, Cardiff, UK
- Systems Immunity Research Institute, Cardiff University, Cardiff, UK
| | - Peter Holmans
- Division of Psychological Medicine and Clinical Neurosciences, Cardiff University, Cardiff, UK
| | - Matthew Hill
- UK Dementia Research Institute at Cardiff, Cardiff University, Hadyn Ellis Building, Maindy Road, Cardiff, CF24 4HQ, UK
| | - Philip R Taylor
- Division of Infection and Immunity, Cardiff University, Cardiff, UK.
- UK Dementia Research Institute at Cardiff, Cardiff University, Hadyn Ellis Building, Maindy Road, Cardiff, CF24 4HQ, UK.
- Systems Immunity Research Institute, Cardiff University, Cardiff, UK.
| |
Collapse
|
7
|
Hosokawa H, Rothenberg EV. How transcription factors drive choice of the T cell fate. Nat Rev Immunol 2021; 21:162-176. [PMID: 32918063 PMCID: PMC7933071 DOI: 10.1038/s41577-020-00426-6] [Citation(s) in RCA: 131] [Impact Index Per Article: 43.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/05/2020] [Indexed: 12/21/2022]
Abstract
Recent evidence has elucidated how multipotent blood progenitors transform their identities in the thymus and undergo commitment to become T cells. Together with environmental signals, a core group of transcription factors have essential roles in this process by directly activating and repressing specific genes. Many of these transcription factors also function in later T cell development, but control different genes. Here, we review how these transcription factors work to change the activities of specific genomic loci during early intrathymic development to establish T cell lineage identity. We introduce the key regulators and highlight newly emergent insights into the rules that govern their actions. Whole-genome deep sequencing-based analysis has revealed unexpectedly rich relationships between inherited epigenetic states, transcription factor-DNA binding affinity thresholds and influences of given transcription factors on the activities of other factors in the same cells. Together, these mechanisms determine T cell identity and make the lineage choice irreversible.
Collapse
Affiliation(s)
- Hiroyuki Hosokawa
- Department of Immunology, Tokai University School of Medicine, Isehara, Kanagawa, Japan
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Ellen V Rothenberg
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA.
| |
Collapse
|
8
|
Hosokawa H, Masuhara K, Koizumi M. Transcription factors regulate early T cell development via redeployment of other factors: Functional dynamics of constitutively required factors in cell fate decisions. Bioessays 2021; 43:e2000345. [PMID: 33624856 DOI: 10.1002/bies.202000345] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Revised: 01/30/2021] [Accepted: 02/08/2021] [Indexed: 01/02/2023]
Abstract
Establishment of cell lineage identity from multipotent progenitors is controlled by cooperative actions of lineage-specific and stably expressed transcription factors, combined with input from environmental signals. Lineage-specific master transcription factors activate and repress gene expression by recruiting consistently expressed transcription factors and chromatin modifiers to their target loci. Recent technical advances in genome-wide and multi-omics analysis have shed light on unexpected mechanisms that underlie more complicated actions of transcription factors in cell fate decisions. In this review, we discuss functional dynamics of stably expressed and continuously required factors, Notch and Runx family members, throughout developmental stages of early T cell development in the thymus. Pre- and post-commitment stage-specific transcription factors induce dynamic redeployment of Notch and Runx binding genomic regions. Thus, together with stage-specific transcription factors, shared transcription factors across distinct developmental stages regulate acquisition of T lineage identity.
Collapse
Affiliation(s)
- Hiroyuki Hosokawa
- Department of Immunology, Tokai University School of Medicine, Isehara, Kanagawa, Japan.,Institute of Medical Sciences, Tokai University, Isehara, Kanagawa, Japan
| | - Kaori Masuhara
- Department of Immunology, Tokai University School of Medicine, Isehara, Kanagawa, Japan
| | - Maria Koizumi
- Department of Immunology, Tokai University School of Medicine, Isehara, Kanagawa, Japan
| |
Collapse
|
9
|
Rothenberg EV, Göttgens B. How haematopoiesis research became a fertile ground for regulatory network biology as pioneered by Eric Davidson. Curr Opin Hematol 2021; 28:1-10. [PMID: 33229891 PMCID: PMC7755131 DOI: 10.1097/moh.0000000000000628] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
PURPOSE OF REVIEW This historical perspective reviews how work of Eric H. Davidson was a catalyst and exemplar for explaining haematopoietic cell fate determination through gene regulation. RECENT FINDINGS Researchers studying blood and immune cells pioneered many of the early mechanistic investigations of mammalian gene regulatory processes. These efforts included the characterization of complex gene regulatory sequences exemplified by the globin and T-cell/B-cell receptor gene loci, as well as the identification of many key regulatory transcription factors through the fine mapping of chromosome translocation breakpoints in leukaemia patients. As the repertoire of known regulators expanded, assembly into gene regulatory network models became increasingly important, not only to account for the truism that regulatory genes do not function in isolation but also to devise new ways of extracting biologically meaningful insights from even more complex information. Here we explore how Eric H. Davidson's pioneering studies of gene regulatory network control in nonvertebrate model organisms have had an important and lasting impact on research into blood and immune cell development. SUMMARY The intellectual framework developed by Davidson continues to contribute to haematopoietic research, and his insistence on demonstrating logic and causality still challenges the frontier of research today.
Collapse
Affiliation(s)
- Ellen V. Rothenberg
- Division of Biology & Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Berthold Göttgens
- Wellcome and MRC Cambridge Stem Cell Institute, Jeffrey Cheah Biomedical Centre, Cambridge Biomedical Campus, Cambridge CB2 0AW, UK
| |
Collapse
|
10
|
Olariu V, Yui MA, Krupinski P, Zhou W, Deichmann J, Andersson E, Rothenberg EV, Peterson C. Multi-scale Dynamical Modeling of T Cell Development from an Early Thymic Progenitor State to Lineage Commitment. Cell Rep 2021; 34:108622. [PMID: 33440162 DOI: 10.1016/j.celrep.2020.108622] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Revised: 04/24/2020] [Accepted: 12/18/2020] [Indexed: 01/13/2023] Open
Abstract
Intrathymic development of committed progenitor (pro)-T cells from multipotent hematopoietic precursors offers an opportunity to dissect the molecular circuitry establishing cell identity in response to environmental signals. This transition encompasses programmed shutoff of stem/progenitor genes, upregulation of T cell specification genes, proliferation, and ultimately commitment. To explain these features in light of reported cis-acting chromatin effects and experimental kinetic data, we develop a three-level dynamic model of commitment based upon regulation of the commitment-linked gene Bcl11b. The levels are (1) a core gene regulatory network (GRN) architecture from transcription factor (TF) perturbation data, (2) a stochastically controlled chromatin-state gate, and (3) a single-cell proliferation model validated by experimental clonal growth and commitment kinetic assays. Using RNA fluorescence in situ hybridization (FISH) measurements of genes encoding key TFs and measured bulk population dynamics, this single-cell model predicts state-switching kinetics validated by measured clonal proliferation and commitment times. The resulting multi-scale model provides a mechanistic framework for dissecting commitment dynamics.
Collapse
Affiliation(s)
- Victor Olariu
- Computational Biology and Biological Physics, Department of Astronomy and Theoretical Physics, Lund University, Lund, Sweden
| | - Mary A Yui
- Division of Biology and Biological Engineering, 156-29, California Institute of Technology, Pasadena, CA 91125, USA
| | - Pawel Krupinski
- Computational Biology and Biological Physics, Department of Astronomy and Theoretical Physics, Lund University, Lund, Sweden
| | - Wen Zhou
- Division of Biology and Biological Engineering, 156-29, California Institute of Technology, Pasadena, CA 91125, USA
| | - Julia Deichmann
- Computational Biology and Biological Physics, Department of Astronomy and Theoretical Physics, Lund University, Lund, Sweden
| | - Emil Andersson
- Computational Biology and Biological Physics, Department of Astronomy and Theoretical Physics, Lund University, Lund, Sweden
| | - Ellen V Rothenberg
- Division of Biology and Biological Engineering, 156-29, California Institute of Technology, Pasadena, CA 91125, USA.
| | - Carsten Peterson
- Computational Biology and Biological Physics, Department of Astronomy and Theoretical Physics, Lund University, Lund, Sweden.
| |
Collapse
|
11
|
Logical modeling of cell fate specification—Application to T cell commitment. Curr Top Dev Biol 2020; 139:205-238. [DOI: 10.1016/bs.ctdb.2020.02.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
|
12
|
Abstract
Specification of multipotent blood precursor cells in postnatal mice to become committed T-cell precursors involves a gene regulatory network of several interacting but functionally distinct modules. Many links of this network have been defined by perturbation tests and by functional genomics. However, using the network model to predict real-life kinetics of the commitment process is still difficult, partly due to the tenacity of repressive chromatin states, and to the ability of transcription factors to affect each other's binding site choices through competitive recruitment to alternative sites ("coregulator theft"). To predict kinetics, future models will need to incorporate mechanistic information about chromatin state change dynamics and more sophisticated understanding of the proteomics and cooperative DNA site choices of transcription factor complexes.
Collapse
Affiliation(s)
- Ellen V Rothenberg
- Division of Biology & Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| |
Collapse
|
13
|
Abstract
In this review, Rothenburg discusses the gene regulatory network and chromatin-based kinetic constraints that determine activities of transcription factors in the primary establishment of T-cell identity. T-cell development in mammals is a model for lineage choice and differentiation from multipotent stem cells. Although T-cell fate choice is promoted by signaling in the thymus through one dominant pathway, the Notch pathway, it entails a complex set of gene regulatory network and chromatin state changes even before the cells begin to express their signature feature, the clonal-specific T-cell receptors (TCRs) for antigen. This review distinguishes three developmental modules for T-cell development, which correspond to cell type specification, TCR expression and selection, and the assignment of cells to different effector types. The first is based on transcriptional regulatory network events, the second is dominated by somatic gene rearrangement and mutation and cell selection, and the third corresponds to establishing a poised state of latent regulator priming through an unknown mechanism. Interestingly, in different lineages, the third module can be deployed at variable times relative to the completion of the first two modules. This review focuses on the gene regulatory network and chromatin-based kinetic constraints that determine activities of transcription factors TCF1, GATA3, PU.1, Bcl11b, Runx1, and E proteins in the primary establishment of T-cell identity.
Collapse
Affiliation(s)
- Ellen V Rothenberg
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California 91125, USA
| |
Collapse
|
14
|
Runx1 promotes murine erythroid progenitor proliferation and inhibits differentiation by preventing Pu.1 downregulation. Proc Natl Acad Sci U S A 2019; 116:17841-17847. [PMID: 31431533 DOI: 10.1073/pnas.1901122116] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Pu.1 is an ETS family transcription factor (TF) that plays critical roles in erythroid progenitors by promoting proliferation and blocking terminal differentiation. However, the mechanisms controlling expression and down-regulation of Pu.1 during early erythropoiesis have not been defined. In this study, we identify the actions of Runx1 and Pu.1 itself at the Pu.1 gene Upstream Regulatory Element (URE) as major regulators of Pu.1 expression in Burst-Forming Unit erythrocytes (BFUe). During early erythropoiesis, Runx1 and Pu.1 levels decline, and chromatin accessibility at the URE is lost. Ectopic expression of Runx1 or Pu.1, both of which bind the URE, prevents Pu.1 down-regulation and blocks terminal erythroid differentiation, resulting in extensive ex vivo proliferation and immortalization of erythroid progenitors. Ectopic expression of Runx1 in BFUe lacking a URE fails to block terminal erythroid differentiation. Thus, Runx1, acting at the URE, and Pu.1 itself directly regulate Pu.1 levels in erythroid cells, and loss of both factors is critical for Pu.1 down-regulation during terminal differentiation. The molecular mechanism of URE inactivation in erythroid cells through loss of TF binding represents a distinct pattern of Pu.1 regulation from those described in other hematopoietic cell types such as T cells which down-regulate Pu.1 through active repression. The importance of down-regulation of Runx1 and Pu.1 in erythropoiesis is further supported by genome-wide analyses showing that their DNA-binding motifs are highly overrepresented in regions that lose chromatin accessibility during early erythroid development.
Collapse
|
15
|
Rothenberg EV, Hosokawa H, Ungerbäck J. Mechanisms of Action of Hematopoietic Transcription Factor PU.1 in Initiation of T-Cell Development. Front Immunol 2019; 10:228. [PMID: 30842770 PMCID: PMC6391351 DOI: 10.3389/fimmu.2019.00228] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2018] [Accepted: 01/28/2019] [Indexed: 12/20/2022] Open
Abstract
PU.1 is an ETS-family transcription factor that plays a broad range of roles in hematopoiesis. A direct regulator of myeloid, dendritic-cell, and B cell functional programs, and a well-known antagonist of terminal erythroid cell differentiation, it is also expressed in the earliest stages of T-cell development of each cohort of intrathymic pro-T cells. Its expression in this context appears to give T-cell precursors initial, transient access to myeloid and dendritic cell developmental competence and therefore to represent a source of antagonism or delay of T-cell lineage commitment. However, it has remained uncertain until recently why T-cell development is also intensely dependent upon PU.1. Here, we review recent work that sheds light on the molecular biology of PU.1 action across the genome in pro-T cells and identifies the genes that depend on PU.1 for their correct regulation. This work indicates modes of chromatin engagement, pioneering, and cofactor recruitment (“coregulator theft”) by PU.1 as well as gene network interactions that not only affect specific target genes but also have system-wide regulatory consequences, amplifying the impact of PU.1 beyond its own direct binding targets. The genes directly regulated by PU.1 also suggest a far-reaching transformation of cell biology and signaling potential between the early stages of T-cell development when PU.1 is expressed and when it is silenced. These cell-biological functions can be important to distinguish fetal from adult T-cell development and have the potential to illuminate aspects of thymic function that have so far remained the most mysterious.
Collapse
Affiliation(s)
- Ellen V Rothenberg
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, United States
| | - Hiroyuki Hosokawa
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, United States
| | - Jonas Ungerbäck
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, United States
| |
Collapse
|
16
|
Hosokawa H, Ungerbäck J, Wang X, Matsumoto M, Nakayama KI, Cohen SM, Tanaka T, Rothenberg EV. Transcription Factor PU.1 Represses and Activates Gene Expression in Early T Cells by Redirecting Partner Transcription Factor Binding. Immunity 2019; 48:1119-1134.e7. [PMID: 29924977 DOI: 10.1016/j.immuni.2018.04.024] [Citation(s) in RCA: 66] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Revised: 02/21/2018] [Accepted: 04/19/2018] [Indexed: 01/09/2023]
Abstract
Transcription factors normally regulate gene expression through their action at sites where they bind to DNA. However, the balance of activating and repressive functions that a transcription factor can mediate is not completely understood. Here, we showed that the transcription factor PU.1 regulated gene expression in early T cell development both by recruiting partner transcription factors to its own binding sites and by depleting them from the binding sites that they preferred when PU.1 was absent. The removal of partner factors Satb1 and Runx1 occurred primarily from sites where PU.1 itself did not bind. Genes linked to sites of partner factor "theft" were enriched for genes that PU.1 represses despite lack of binding, both in a model cell line system and in normal T cell development. Thus, system-level competitive recruitment dynamics permit PU.1 to affect gene expression both through its own target sites and through action at a distance.
Collapse
Affiliation(s)
- Hiroyuki Hosokawa
- Division of Biology & Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Jonas Ungerbäck
- Division of Biology & Biological Engineering, California Institute of Technology, Pasadena, CA, USA; Division of Molecular Hematology, Lund University, Sweden
| | - Xun Wang
- Division of Biology & Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Masaki Matsumoto
- Department of Molecular and Cellular Biology, Medical Institute of Bioregulation, Kyushu University, Japan
| | - Keiichi I Nakayama
- Department of Molecular and Cellular Biology, Medical Institute of Bioregulation, Kyushu University, Japan
| | - Sarah M Cohen
- Division of Biology & Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Tomoaki Tanaka
- Department of Molecular Diagnosis, Graduate School of Medicine, Chiba University, Japan; AMED-CREST, AMED, Japan Agency for Medical Research and Development, Tokyo, Japan
| | - Ellen V Rothenberg
- Division of Biology & Biological Engineering, California Institute of Technology, Pasadena, CA, USA.
| |
Collapse
|
17
|
RUNX1 promotes cell growth in human T-cell acute lymphoblastic leukemia by transcriptional regulation of key target genes. Exp Hematol 2018; 64:84-96. [DOI: 10.1016/j.exphem.2018.04.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Revised: 04/19/2018] [Accepted: 04/27/2018] [Indexed: 11/23/2022]
|
18
|
Bcl11b and combinatorial resolution of cell fate in the T-cell gene regulatory network. Proc Natl Acad Sci U S A 2018; 114:5800-5807. [PMID: 28584128 DOI: 10.1073/pnas.1610617114] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
T-cell development from hematopoietic progenitors depends on multiple transcription factors, mobilized and modulated by intrathymic Notch signaling. Key aspects of T-cell specification network architecture have been illuminated through recent reports defining roles of transcription factors PU.1, GATA-3, and E2A, their interactions with Notch signaling, and roles of Runx1, TCF-1, and Hes1, providing bases for a comprehensively updated model of the T-cell specification gene regulatory network presented herein. However, the role of lineage commitment factor Bcl11b has been unclear. We use self-organizing maps on 63 RNA-seq datasets from normal and perturbed T-cell development to identify functional targets of Bcl11b during commitment and relate them to other regulomes. We show that both activation and repression target genes can be bound by Bcl11b in vivo, and that Bcl11b effects overlap with E2A-dependent effects. The newly clarified role of Bcl11b distinguishes discrete components of commitment, resolving how innate lymphoid, myeloid, and dendritic, and B-cell fate alternatives are excluded by different mechanisms.
Collapse
|
19
|
Hosokawa H, Rothenberg EV. Cytokines, Transcription Factors, and the Initiation of T-Cell Development. Cold Spring Harb Perspect Biol 2018; 10:cshperspect.a028621. [PMID: 28716889 DOI: 10.1101/cshperspect.a028621] [Citation(s) in RCA: 99] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Multipotent blood progenitor cells migrate into the thymus and initiate the T-cell differentiation program. T-cell progenitor cells gradually acquire T-cell characteristics while shedding their multipotentiality for alternative fates. This process is supported by extracellular signaling molecules, including Notch ligands and cytokines, provided by the thymic microenvironment. T-cell development is associated with dynamic change of gene regulatory networks of transcription factors, which interact with these environmental signals. Together with Notch or pre-T-cell-receptor (TCR) signaling, cytokines always control proliferation, survival, and differentiation of early T cells, but little is known regarding their cross talk with transcription factors. However, recent results suggest ways that cytokines expressed in distinct intrathymic niches can specifically modulate key transcription factors. This review discusses how stage-specific roles of cytokines and transcription factors can jointly guide development of early T cells.
Collapse
Affiliation(s)
- Hiroyuki Hosokawa
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California 91125
| | - Ellen V Rothenberg
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California 91125
| |
Collapse
|
20
|
Montecino-Rodriguez E, Casero D, Fice M, Le J, Dorshkind K. Differential Expression of PU.1 and Key T Lineage Transcription Factors Distinguishes Fetal and Adult T Cell Development. THE JOURNAL OF IMMUNOLOGY 2018; 200:2046-2056. [PMID: 29436414 DOI: 10.4049/jimmunol.1701336] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Accepted: 01/16/2018] [Indexed: 01/11/2023]
Abstract
The PU.1 transcription factor plays a critical role in the regulation of T cell development, so a report that it is dispensable for fetal thymopoiesis is puzzling. To understand this paradox, we examined the requirement for PU.1, encoded by Spi1, during fetal, neonatal, and adult thymopoiesis in a PU.1 hypomorphic mouse generated by deletion of the Spi1 14-kb upstream regulatory element and by analysis of patterns of gene expression in fetal and adult T cell progenitors. Our data demonstrate that the initiation of thymopoiesis during early gestation is less dependent on PU.1 compared with T cell differentiation in adults and that fetal T cell progenitors express lower levels of Spi1 compared with their adult counterparts. We also show that expression of the core network of T lineage transcription factors regulated by PU.1 differs in fetal and adult T cell progenitors. In particular, PU.1-regulated genes that promote T cell differentiation are differentially expressed in fetal versus adult early T lineage progenitors. These results indicate that the transcriptional differences between the fetal and adult T cell developmental programs are driven in part by differential levels of PU.1 expression and that this likely underlies the differences in the properties of fetal and adult T cell progenitors.
Collapse
Affiliation(s)
- Encarnacion Montecino-Rodriguez
- Department of Pathology and Laboratory Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA 90095
| | - David Casero
- Department of Pathology and Laboratory Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA 90095
| | - Michael Fice
- Department of Pathology and Laboratory Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA 90095
| | - Jonathan Le
- Department of Pathology and Laboratory Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA 90095
| | - Kenneth Dorshkind
- Department of Pathology and Laboratory Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA 90095
| |
Collapse
|
21
|
Rothenberg EV, Kueh HY, Yui MA, Zhang JA. Hematopoiesis and T-cell specification as a model developmental system. Immunol Rev 2016; 271:72-97. [PMID: 27088908 DOI: 10.1111/imr.12417] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The pathway to generate T cells from hematopoietic stem cells guides progenitors through a succession of fate choices while balancing differentiation progression against proliferation, stage to stage. Many elements of the regulatory system that controls this process are known, but the requirement for multiple, functionally distinct transcription factors needs clarification in terms of gene network architecture. Here, we compare the features of the T-cell specification system with the rule sets underlying two other influential types of gene network models: first, the combinatorial, hierarchical regulatory systems that generate the orderly, synchronized increases in complexity in most invertebrate embryos; second, the dueling 'master regulator' systems that are commonly used to explain bistability in microbial systems and in many fate choices in terminal differentiation. The T-cell specification process shares certain features with each of these prevalent models but differs from both of them in central respects. The T-cell system is highly combinatorial but also highly dose-sensitive in its use of crucial regulatory factors. The roles of these factors are not always T-lineage-specific, but they balance and modulate each other's activities long before any mutually exclusive silencing occurs. T-cell specification may provide a new hybrid model for gene networks in vertebrate developmental systems.
Collapse
Affiliation(s)
- Ellen V Rothenberg
- Division of Biology & Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Hao Yuan Kueh
- Division of Biology & Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Mary A Yui
- Division of Biology & Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Jingli A Zhang
- Division of Biology & Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| |
Collapse
|
22
|
Montecino-Rodriguez E, Fice M, Casero D, Berent-Maoz B, Barber CL, Dorshkind K. Distinct Genetic Networks Orchestrate the Emergence of Specific Waves of Fetal and Adult B-1 and B-2 Development. Immunity 2016; 45:527-539. [PMID: 27566938 DOI: 10.1016/j.immuni.2016.07.012] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Revised: 05/13/2016] [Accepted: 06/08/2016] [Indexed: 10/21/2022]
Abstract
B cell development is often depicted as a linear process initiating in the fetus and continuing postnatally. Using a PU.1 hypomorphic mouse model, we found that B-1 and B-2 lymphopoiesis occurred in distinct fetal and adult waves differentially dependent on the Sfpi1 14 kB upstream regulatory element. The initial wave of fetal B-1 development was absent in PU.1 hypomorphic mice, while subsequent fetal and adult waves emerged. In contrast, B-2 lymphopoiesis occurred in distinct fetal and adult waves. Whole-transcriptome profiling of fetal and adult B cell progenitors supported the existence of three waves of B-1 and two waves of B-2 development and revealed that the network of transcription factors governing B lineage specification and commitment was highly divergent between B-1 and B-2 progenitors. These findings support the view that the B-1 and B-2 lineages are distinct and provide a genetic basis for layering of immune system development.
Collapse
Affiliation(s)
- Encarnacion Montecino-Rodriguez
- Department of Pathology and Laboratory Medicine, Division of Hematology/Oncology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Michael Fice
- Department of Pathology and Laboratory Medicine, Division of Hematology/Oncology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - David Casero
- Department of Pathology and Laboratory Medicine, Division of Hematology/Oncology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Beata Berent-Maoz
- Department of Medicine, Division of Hematology/Oncology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Chad L Barber
- Department of Biology, California Lutheran University, Thousand Oaks, CA 91360, USA
| | - Kenneth Dorshkind
- Department of Pathology and Laboratory Medicine, Division of Hematology/Oncology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA.
| |
Collapse
|
23
|
Manesso E, Kueh HY, Freedman G, Rothenberg EV, Peterson C. Irreversibility of T-Cell Specification: Insights from Computational Modelling of a Minimal Network Architecture. PLoS One 2016; 11:e0161260. [PMID: 27551921 PMCID: PMC4995000 DOI: 10.1371/journal.pone.0161260] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2016] [Accepted: 08/02/2016] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND/OBJECTIVES A cascade of gene activations under the control of Notch signalling is required during T-cell specification, when T-cell precursors gradually lose the potential to undertake other fates and become fully committed to the T-cell lineage. We elucidate how the gene/protein dynamics for a core transcriptional module governs this important process by computational means. METHODS We first assembled existing knowledge about transcription factors known to be important for T-cell specification to form a minimal core module consisting of TCF-1, GATA-3, BCL11B, and PU.1 aiming at dynamical modeling. Model architecture was based on published experimental measurements of the effects on each factor when each of the others is perturbed. While several studies provided gene expression measurements at different stages of T-cell development, pure time series are not available, thus precluding a straightforward study of the dynamical interactions among these genes. We therefore translate stage dependent data into time series. A feed-forward motif with multiple positive feed-backs can account for the observed delay between BCL11B versus TCF-1 and GATA-3 activation by Notch signalling. With a novel computational approach, all 32 possible interactions among Notch signalling, TCF-1, and GATA-3 are explored by translating combinatorial logic expressions into differential equations for BCL11B production rate. RESULTS Our analysis reveals that only 3 of 32 possible configurations, where GATA-3 works as a dimer, are able to explain not only the time delay, but very importantly, also give rise to irreversibility. The winning models explain the data within the 95% confidence region and are consistent with regard to decay rates. CONCLUSIONS This first generation model for early T-cell specification has relatively few players. Yet it explains the gradual transition into a committed state with no return. Encoding logics in a rate equation setting allows determination of binding properties beyond what is possible in a Boolean network.
Collapse
Affiliation(s)
- Erica Manesso
- Computational Biology and Biological Physics, Department of Astronomy and Theoretical Physics, Lund University, SE-223 62 Lund, Sweden
| | - Hao Yuan Kueh
- Division of Biology, California Institute of Technology, Pasadena, CA 91125, United States of America
| | - George Freedman
- Division of Biology, California Institute of Technology, Pasadena, CA 91125, United States of America
| | - Ellen V. Rothenberg
- Division of Biology, California Institute of Technology, Pasadena, CA 91125, United States of America
- * E-mail: (EVR); (CP)
| | - Carsten Peterson
- Computational Biology and Biological Physics, Department of Astronomy and Theoretical Physics, Lund University, SE-223 62 Lund, Sweden
- * E-mail: (EVR); (CP)
| |
Collapse
|
24
|
Asynchronous combinatorial action of four regulatory factors activates Bcl11b for T cell commitment. Nat Immunol 2016; 17:956-65. [PMID: 27376470 PMCID: PMC4955789 DOI: 10.1038/ni.3514] [Citation(s) in RCA: 101] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Accepted: 06/14/2016] [Indexed: 12/28/2022]
Abstract
During T cell development, multipotent progenitors relinquish competence for other fates and commit to the T cell lineage by turning on the transcription factor Bcl11b. To clarify lineage commitment mechanisms, we followed developing T cells at single-cell level using Bcl11b knock-in fluorescent reporter mice. Notch signaling and Notch-activated transcription factors collaborate to activate Bcl11b expression, irrespective of Notch-dependent proliferation. These inputs work via three distinct, asynchronous mechanisms: an early locus poising function dependent on TCF-1 and GATA-3; a stochastic permissivity function dependent on Notch signaling; and a separate amplitude-control function dependent on Runx1, a factor already present in multipotent progenitors. Despite all being necessary for Bcl11b activation, these inputs act in a stage specific manner, providing a multi-tiered mechanism for developmental gene regulation.
Collapse
|
25
|
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.
Collapse
Affiliation(s)
- Patrick I Ferrell
- Department of Medicine, University of Minnesota, Minneapolis, Minnesota, USA; Stem Cell Institute, University of Minnesota, Minneapolis, Minnesota, USA
| | | | | | | | | |
Collapse
|
26
|
Rothenberg EV, Ungerbäck J, Champhekar A. Forging T-Lymphocyte Identity: Intersecting Networks of Transcriptional Control. Adv Immunol 2015; 129:109-74. [PMID: 26791859 DOI: 10.1016/bs.ai.2015.09.002] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
T-lymphocyte development branches off from other lymphoid developmental programs through its requirement for sustained environmental signals through the Notch pathway. In the thymus, Notch signaling induces a succession of T-lineage regulatory factors that collectively create the T-cell identity through distinct steps. This process involves both the staged activation of T-cell identity genes and the staged repression of progenitor-cell-inherited regulatory genes once their roles in self-renewal and population expansion are no longer needed. With the recent characterization of innate lymphoid cells (ILCs) that share transcriptional regulation programs extensively with T-cell subsets, T-cell identity can increasingly be seen as defined in modular terms, as the processes selecting and actuating effector function are potentially detachable from the processes generating and selecting clonally unique T-cell receptor structures. The developmental pathways of different classes of T cells and ILCs are distinguished by the numbers of prerequisites of gene rearrangement, selection, and antigen contact before the cells gain access to nearly common regulatory mechanisms for choosing effector function. Here, the major classes of transcription factors that interact with Notch signals during T-lineage specification are discussed in terms of their roles in these programs, the evidence for their spectra of target genes at different stages, and their cross-regulatory and cooperative actions with each other. Specific topics include Notch modulation of PU.1 and GATA-3, PU.1-Notch competition, the relationship between PU.1 and GATA-3, and the roles of E proteins, Bcl11b, and GATA-3 in guiding acquisition of T-cell identity while avoiding redirection to an ILC fate.
Collapse
Affiliation(s)
- Ellen V Rothenberg
- Division of Biology & Biological Engineering, California Institute of Technology, Pasadena, California, USA.
| | - Jonas Ungerbäck
- Division of Biology & Biological Engineering, California Institute of Technology, Pasadena, California, USA; Department of Clinical and Experimental Medicine, Experimental Hematopoiesis Unit, Faculty of Health Sciences, Linköping University, Linköping, Sweden
| | - Ameya Champhekar
- Department of Microbiology, Immunology, and Molecular Genetics, University of California Los Angeles, Los Angeles, California, USA
| |
Collapse
|
27
|
Scripture-Adams DD, Damle SS, Li L, Elihu KJ, Qin S, Arias AM, Butler RR, Champhekar A, Zhang JA, Rothenberg EV. GATA-3 dose-dependent checkpoints in early T cell commitment. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2014; 193:3470-91. [PMID: 25172496 PMCID: PMC4170028 DOI: 10.4049/jimmunol.1301663] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
GATA-3 expression is crucial for T cell development and peaks during commitment to the T cell lineage, midway through the CD4(-)CD8(-) (double-negative [DN]) stages 1-3. We used RNA interference and conditional deletion to reduce GATA-3 protein acutely at specific points during T cell differentiation in vitro. Even moderate GATA-3 reduction killed DN1 cells, delayed progression to the DN2 stage, skewed DN2 gene regulation, and blocked appearance of the DN3 phenotype. Although a Bcl-2 transgene rescued DN1 survival and improved DN2 cell generation, it did not restore DN3 differentiation. Gene expression analyses (quantitative PCR, RNA sequencing) showed that GATA-3-deficient DN2 cells quickly upregulated genes, including Spi1 (PU.1) and Bcl11a, and downregulated genes, including Cpa3, Ets1, Zfpm1, Bcl11b, Il9r, and Il17rb with gene-specific kinetics and dose dependencies. These targets could mediate two distinct roles played by GATA-3 in lineage commitment, as revealed by removing wild-type or GATA-3-deficient early T lineage cells from environmental Notch signals. GATA-3 worked as a potent repressor of B cell potential even at low expression levels, so that only full deletion of GATA-3 enabled pro-T cells to reveal B cell potential. The ability of GATA-3 to block B cell development did not require T lineage commitment factor Bcl11b. In prethymic multipotent precursors, however, titration of GATA-3 activity using tamoxifen-inducible GATA-3 showed that GATA-3 inhibits B and myeloid developmental alternatives at different threshold doses. Furthermore, differential impacts of a GATA-3 obligate repressor construct imply that B and myeloid development are inhibited through distinct transcriptional mechanisms. Thus, the pattern of GATA-3 expression sequentially produces B lineage exclusion, T lineage progression, and myeloid-lineage exclusion for commitment.
Collapse
Affiliation(s)
- Deirdre D Scripture-Adams
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125
| | - Sagar S Damle
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125
| | - Long Li
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125
| | - Koorosh J Elihu
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125
| | - Shuyang Qin
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125
| | - Alexandra M Arias
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125
| | - Robert R Butler
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125
| | - Ameya Champhekar
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125
| | - Jingli A Zhang
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125
| | - Ellen V Rothenberg
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125
| |
Collapse
|
28
|
Yui MA, Rothenberg EV. Developmental gene networks: a triathlon on the course to T cell identity. Nat Rev Immunol 2014; 14:529-45. [PMID: 25060579 PMCID: PMC4153685 DOI: 10.1038/nri3702] [Citation(s) in RCA: 230] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Cells acquire their ultimate identities by activating combinations of transcription factors that initiate and sustain expression of the appropriate cell type-specific genes. T cell development depends on the progression of progenitor cells through three major phases, each of which is associated with distinct transcription factor ensembles that control the recruitment of these cells to the thymus, their proliferation, lineage commitment and responsiveness to T cell receptor signals, all before the allocation of cells to particular effector programmes. All three phases are essential for proper T cell development, as are the mechanisms that determine the boundaries between each phase. Cells that fail to shut off one set of regulators before the next gene network phase is activated are predisposed to leukaemic transformation.
Collapse
Affiliation(s)
- Mary A Yui
- Division of Biology 156-29, California Institute of Technology, Pasadena, California 91125, USA
| | - Ellen V Rothenberg
- Division of Biology 156-29, California Institute of Technology, Pasadena, California 91125, USA
| |
Collapse
|
29
|
Abstract
T and B cells share a common somatic gene rearrangement mechanism for assembling the genes that code for their antigen receptors; they also have developmental pathways with many parallels. Shared usage of basic helix-loop-helix E proteins as transcriptional drivers underlies these common features. However, the transcription factor networks in which these E proteins are embedded are different both in membership and in architecture for T and B cell gene regulatory programs. These differences permit lineage commitment decisions to be made in different hierarchical orders. Furthermore, in contrast to B cell gene networks, the T cell gene network architecture for effector differentiation is sufficiently modular so that E protein inputs can be removed. Complete T cell-like effector differentiation can proceed without T cell receptor rearrangement or selection when E proteins are neutralized, yielding natural killer and other innate lymphoid cells.
Collapse
Affiliation(s)
- Ellen V Rothenberg
- Division of Biology, California Institute of Technology, Pasadena, California 91125;
| |
Collapse
|
30
|
Rothenberg EV, Champhekar A, Damle S, Del Real MM, Kueh HY, Li L, Yui MA. Transcriptional establishment of cell-type identity: dynamics and causal mechanisms of T-cell lineage commitment. COLD SPRING HARBOR SYMPOSIA ON QUANTITATIVE BIOLOGY 2013; 78:31-41. [PMID: 24135716 DOI: 10.1101/sqb.2013.78.020271] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Precursor cell entry into the T-cell developmental pathway can be divided into two phases by the closure of T-lineage commitment. As cells decide against the last alternative options to the T-cell fate, they turn on the transcription factor Bcl11b and silence expression of a group of multipotent progenitor regulatory factors that include hematopoietic transcription factor PU.1. Functional perturbation tests show that Bcl11b is needed for commitment while PU.1 actively participates in keeping open access to alternative fates, until it is silenced; however, PU.1 and Bcl11b both contribute positively to T-cell development. Our recent work reviewed here sheds light on the transcriptional regulatory network that determines the timing and irreversibility of Bcl11b activation, the ways that Notch signaling from the thymic microenvironment restricts the action of PU.1 to prevent it from diverting cells to non-T fates, and the target genes that PU.1 still regulates under the influence of Notch signaling to contribute to T-cell generation. We argue that T-cell development depends on the sequential operation of two interlaced, but mutually antagonistic, gene regulatory networks, one initially supporting expansion before commitment and the other imposing a "terminal" differentiation process on committed cells.
Collapse
Affiliation(s)
- Ellen V Rothenberg
- Division of Biology 156-29, California Institute of Technology, Pasadena, California 91125
| | - Ameya Champhekar
- Division of Biology 156-29, California Institute of Technology, Pasadena, California 91125
| | - Sagar Damle
- Division of Biology 156-29, California Institute of Technology, Pasadena, California 91125
| | | | - Hao Yuan Kueh
- Division of Biology 156-29, California Institute of Technology, Pasadena, California 91125
| | - Long Li
- Division of Biology 156-29, California Institute of Technology, Pasadena, California 91125
| | - Mary A Yui
- Division of Biology 156-29, California Institute of Technology, Pasadena, California 91125
| |
Collapse
|
31
|
DNA methylation-mediated silencing of PU.1 in leukemia cells resistant to cell differentiation. SPRINGERPLUS 2013; 2:392. [PMID: 24010046 PMCID: PMC3758488 DOI: 10.1186/2193-1801-2-392] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/24/2013] [Accepted: 08/13/2013] [Indexed: 11/20/2022]
Abstract
In mice, the proviral integration of the Friend Spleen Focus Forming Virus (SFFV) within the PU.1 locus of erythroid precursors results in the development of erythroleukemia. SFFV integrates several kilobases upstream of the PU.1 transcription initiation start site leading to the constitutive activation of the gene which in turn results in a block of erythroid differentiation. In this study we have mapped and sequenced the exact location of the retroviral integration site. We have shown that SFFV integrates downstream of a previously described upstream regulatory element (URE), precisely 2,976 bp downstream of the URE-distal element. We have also found that SFFV persists integrated within the same location in resistant cell lines that have lost their differentiation capacity and in which case PU.1 remains silent. We have examined the methylation status of PU.1 and found that in resistant cells the nearby CpG islands remained methylated in contrast to a non-methylated status of the parental cell lines. Treatment with 5-aza-2′-deoxycytidine caused resistant cells to differentiate yet only when combined with HMBA. Altogether these results strongly suggest that methylation plays a crucial role with regard to PU.1 silencing. However, although demethylation is required, it is not sufficient to overcome the differentiation impasse. We have also showed that activation blockage of the Epo/Epo-R pathway remains despite of the absence of PU.1.
Collapse
|
32
|
Kueh HY, Champhekar A, Champhekhar A, Nutt SL, Elowitz MB, Rothenberg EV. Positive feedback between PU.1 and the cell cycle controls myeloid differentiation. Science 2013; 341:670-3. [PMID: 23868921 DOI: 10.1126/science.1240831] [Citation(s) in RCA: 203] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Regulatory gene circuits with positive-feedback loops control stem cell differentiation, but several mechanisms can contribute to positive feedback. Here, we dissect feedback mechanisms through which the transcription factor PU.1 controls lymphoid and myeloid differentiation. Quantitative live-cell imaging revealed that developing B cells decrease PU.1 levels by reducing PU.1 transcription, whereas developing macrophages increase PU.1 levels by lengthening their cell cycles, which causes stable PU.1 accumulation. Exogenous PU.1 expression in progenitors increases endogenous PU.1 levels by inducing cell cycle lengthening, implying positive feedback between a regulatory factor and the cell cycle. Mathematical modeling showed that this cell cycle-coupled feedback architecture effectively stabilizes a slow-dividing differentiated state. These results show that cell cycle duration functions as an integral part of a positive autoregulatory circuit to control cell fate.
Collapse
Affiliation(s)
- Hao Yuan Kueh
- Division of Biology, California Institute of Technology, Pasadena, CA, USA.
| | | | | | | | | | | |
Collapse
|
33
|
Abstract
Bcl11b is a T-cell specific gene in hematopoiesis that begins expression during T-lineage commitment and is required for this process. Aberrant expression of BCL11B or proto-oncogene translocation to the vicinity of BCL11B can be a contributing factor in human T-ALL. To identify the mechanism that controls its distinctive T-lineage expression, we corrected the identified Bcl11b transcription start site and mapped a cell-type-specific differentially methylated region bracketing the Bcl11b promoter. We identified a 1.9-kb region 850 kb downstream of Bcl11b, "Major Peak," distinguished by its dynamic histone marking pattern in development that mirrors the pattern at the Bcl11b promoter. Looping interactions between promoter-proximal elements including the differentially methylated region and downstream elements in the Major Peak are required to recapitulate the T-cell specific expression of Bcl11b in stable reporter assays. Functional dissection of the Major Peak sequence showed distinct subregions, in which TCF-1 sites and a conserved element were required for T-lineage-specific activation and silencing in non-T cells. A bacterial artificial chromosome encompassing the full Bcl11b gene still required the addition of the Major Peak to exhibit T-cell specific expression. Thus, promoter-proximal and Major Peak sequences are cis-regulatory elements that interact over 850 kb to control expression of Bcl11b in hematopoietic cells.
Collapse
|
34
|
Alcina A, Fedetz M, Fernández O, Saiz A, Izquierdo G, Lucas M, Leyva L, García-León JA, Abad-Grau MDM, Alloza I, Antigüedad A, Garcia-Barcina MJ, Vandenbroeck K, Varadé J, de la Hera B, Arroyo R, Comabella M, Montalban X, Petit-Marty N, Navarro A, Otaegui D, Olascoaga J, Blanco Y, Urcelay E, Matesanz F. Identification of a functional variant in the KIF5A-CYP27B1-METTL1-FAM119B locus associated with multiple sclerosis. J Med Genet 2012; 50:25-33. [PMID: 23160276 PMCID: PMC3538279 DOI: 10.1136/jmedgenet-2012-101085] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Background and aim Several studies have highlighted the association of the 12q13.3–12q14.1 region with coeliac disease, type 1 diabetes, rheumatoid arthritis and multiple sclerosis (MS); however, the causal variants underlying diseases are still unclear. The authors sought to identify the functional variant of this region associated with MS. Methods Tag-single nucleotide polymorphism (SNP) analysis of the associated region encoding 15 genes was performed in 2876 MS patients and 2910 healthy Caucasian controls together with expression regulation analyses. Results rs6581155, which tagged 18 variants within a region where 9 genes map, was sufficient to model the association. This SNP was in total linkage disequilibrium (LD) with other polymorphisms that associated with the expression levels of FAM119B, AVIL, TSFM, TSPAN31 and CYP27B1 genes in different expression quantitative trait loci studies. Functional annotations from Encyclopedia of DNA Elements (ENCODE) showed that six out of these rs6581155-tagged-SNPs were located in regions with regulatory potential and only one of them, rs10877013, exhibited allele-dependent (ratio A/G=9.5-fold) and orientation-dependent (forward/reverse=2.7-fold) enhancer activity as determined by luciferase reporter assays. This enhancer is located in a region where a long-range chromatin interaction among the promoters and promoter-enhancer of several genes has been described, possibly affecting their expression simultaneously. Conclusions This study determines a functional variant which alters the enhancer activity of a regulatory element in the locus affecting the expression of several genes and explains the association of the 12q13.3–12q14.1 region with MS.
Collapse
Affiliation(s)
- Antonio Alcina
- Department of Cell Biology and Immunology Instituto de Parasitología y Biomedicina López Neyra, Consejo Superior de Investigaciones Científicas (IPBLNCSIC), Granada, Spain
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
35
|
Zhang JA, Mortazavi A, Williams BA, Wold BJ, Rothenberg EV. Dynamic transformations of genome-wide epigenetic marking and transcriptional control establish T cell identity. Cell 2012; 149:467-82. [PMID: 22500808 DOI: 10.1016/j.cell.2012.01.056] [Citation(s) in RCA: 279] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2011] [Revised: 11/29/2011] [Accepted: 01/26/2012] [Indexed: 11/16/2022]
Abstract
T cell development comprises a stepwise process of commitment from a multipotent precursor. To define molecular mechanisms controlling this progression, we probed five stages spanning the commitment process using RNA-seq and ChIP-seq to track genome-wide shifts in transcription, cohorts of active transcription factor genes, histone modifications at diverse classes of cis-regulatory elements, and binding repertoire of GATA-3 and PU.1, transcription factors with complementary roles in T cell development. The results highlight potential promoter-distal cis-regulatory elements in play and reveal both activation sites and diverse mechanisms of repression that silence genes used in alternative lineages. Histone marking is dynamic and reversible, and though permissive marks anticipate, repressive marks often lag behind changes in transcription. In vivo binding of PU.1 and GATA-3 relative to epigenetic marking reveals distinctive factor-specific rules for recruitment of these crucial transcription factors to different subsets of their potential sites, dependent on dose and developmental context.
Collapse
Affiliation(s)
- Jingli A Zhang
- Division of Biology 156-29, California Institute of Technology, Pasadena, CA 91125, USA
| | | | | | | | | |
Collapse
|
36
|
Zarnegar MA, Rothenberg EV. Ikaros represses and activates PU.1 cell-type-specifically through the multifunctional Sfpi1 URE and a myeloid specific enhancer. Oncogene 2012; 31:4647-54. [PMID: 22231443 DOI: 10.1038/onc.2011.597] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Generation of myeloid and lymphoid cells from progenitors involves dynamic changes in transcription factor expression and use, and disruption of hematopoietic transcription factor function and expression can contribute to leukemic transformation. PU.1 and Ikaros are pivotal factors whose expression and utilization are dynamically altered during hematopoietic development. Here, we demonstrate that expression of PU.1, encoded by the Sfpi1 gene, is divergently regulated by Ikaros in distinct cell type-specific contexts. Chromatin immune precipitation analysis and functional perturbations revealed that Ikaros can directly repress or activate Sfpi1 transcription via different PU.1 cis-elements, with PU.1 and Ikaros collaborating at myeloid-specific elements but not at other elements. Our results thus shed light on how PU.1 and Ikaros can act as lineage competency factors to facilitate both myeloid and lymphoid developmental programs.
Collapse
Affiliation(s)
- M A Zarnegar
- Division of Biology, California Institute of Technology, Pasadena, CA 91125, USA
| | | |
Collapse
|
37
|
Rothenberg EV. T cell lineage commitment: identity and renunciation. THE JOURNAL OF IMMUNOLOGY 2011; 186:6649-55. [PMID: 21646301 DOI: 10.4049/jimmunol.1003703] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Precursors undertaking T cell development shed their access to other pathways in a sequential process that begins before entry into the thymus and continues through many cell cycles afterward. This process involves three levels of regulatory change, in which the cells' intrinsic transcriptional regulatory factors, expression of signaling receptors (e.g., Notch1), and expression of distinct homing receptors separately contribute to confirmation of T cell identity. Each alternative potential has a different underlying molecular basis that is neutralized and then permanently silenced through different mechanisms in early T cell precursors. This regulatory mosaic has notable implications for the hierarchy of relationships linking T lymphocytes to other hematopoietic fates.
Collapse
Affiliation(s)
- Ellen V Rothenberg
- Division of Biology, California Institute of Technology, Pasadena, CA 91125, USA.
| |
Collapse
|
38
|
Thompson PK, Zúñiga-Pflücker JC. On becoming a T cell, a convergence of factors kick it up a Notch along the way. Semin Immunol 2011; 23:350-9. [PMID: 21981947 DOI: 10.1016/j.smim.2011.08.007] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/18/2010] [Accepted: 08/19/2011] [Indexed: 12/18/2022]
Abstract
The thymus is seeded by bone marrow-derived progenitors, which undergo a series of differentiation and proliferation events in order to generate functional T lymphocytes. The Notch signaling pathway, together with multiple transcription factors, act in concert to commit progenitors to a T-lineage fate, extinguishing non-T cell potential, inducing thymocyte differentiation and supporting proliferation and survival along the way to becoming a mature T cell. This review focuses on recent evidence regarding the complex interplay between the Notch pathway and other key transcription factors at specific lineage-decision points during the program of T cell development.
Collapse
Affiliation(s)
- Patrycja K Thompson
- Department of Immunology, University of Toronto, Sunnybrook Research Institute, Toronto, Ontario M4N 3M5, Canada
| | | |
Collapse
|
39
|
Kueh HY, Rothenberg EV. Regulatory gene network circuits underlying T cell development from multipotent progenitors. WILEY INTERDISCIPLINARY REVIEWS-SYSTEMS BIOLOGY AND MEDICINE 2011; 4:79-102. [PMID: 21976153 DOI: 10.1002/wsbm.162] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Regulatory gene circuits enable stem and progenitor cells to detect and process developmental signals and make irreversible fate commitment decisions. To gain insight into the gene circuits underlying T cell fate decision making in progenitor cells, we generated an updated T-lymphocyte developmental gene regulatory network from genes and connections found in the literature. This reconstruction allowed us to identify candidate regulatory gene circuit elements underlying T cell fate decision making. Here, we examine the roles of these circuits in facilitating different aspects of the decision making process, and discuss experiments to further probe their structure and function.
Collapse
Affiliation(s)
- Hao Yuan Kueh
- Division of Biology, California Institute of Technology, Pasadena, CA, USA
| | | |
Collapse
|
40
|
Abstract
T-cell development from stem cells has provided a highly accessible and detailed view of the regulatory processes that can go into the choice of a cell fate in a postembryonic, stem cell-based system. But it has been a view from the outside. The problems in understanding the regulatory basis for this lineage choice begin with the fact that too many transcription factors are needed to provide crucial input: without any one of them, T-cell development fails. Furthermore, almost all the factors known to provide crucial functions during the climax of T-lineage commitment itself are also vital for earlier functions that establish the pool of multilineage precursors that would normally feed into the T-cell specification process. When the regulatory genes that encode them are mutated, the confounding effects on earlier stages make it difficult to dissect T-cell specification genetically. Yet both the positive and the negative regulatory events involved in the choice of a T-cell fate are actually a mosaic of distinct functions. New evidence has emerged recently that finally provides a way to separate the major components that fit together to drive this process. Here, we review insights into T-cell specification and commitment that emerge from a combination of molecular, cellular, and systems biology approaches. The results reveal the regulatory structure underlying this lineage decision.
Collapse
Affiliation(s)
- Ellen V Rothenberg
- Division of Biology, California Institute of Technology, Pasadena, CA 91125, USA.
| | | | | |
Collapse
|
41
|
Decker E, Durand C, Bender S, Rödelsperger C, Glaser A, Hecht J, Schneider KU, Rappold G. FGFR3 is a target of the homeobox transcription factor SHOX in limb development. Hum Mol Genet 2011; 20:1524-35. [PMID: 21273290 DOI: 10.1093/hmg/ddr030] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The short stature homeobox gene SHOX encodes a transcription factor which is important for normal limb development. In humans, SHOX deficiency has been associated with various short stature syndromes including Leri-Weill dyschondrosteosis (LWD), Langer mesomelic dysplasia and Turner syndrome as well as non-syndromic idiopathic short stature. A common feature of these syndromes is disproportionate short stature with a particular shortening of the forearms and lower legs. In our studies employing microarray analyses and cell culture experiments, we revealed a strong positive effect of SHOX on the expression of the fibroblast growth factor receptor gene FGFR3, another well-known factor for limb development. Luciferase reporter gene assays show that SHOX activates the extended FGFR3 promoter, and results from chromatin immunoprecipitation (ChIP)-sequencing, ChIP and electrophoretic mobility shift assay experiments suggest a direct binding of SHOX to multiple upstream sequences of FGFR3. To further investigate these regulations in a cellular system for limb development, the effect of viral overexpression of Shox in limb bud derived chicken micromass cultures was tested. We found that Fgfr3 was negatively regulated by Shox, as demonstrated by quantitative real-time polymerase chain reaction and in situ hybridization. This repressive effect might explain the almost mutually exclusive expression patterns of Fgfr3 and Shox in embryonic chicken limbs. A negative regulation that occurs mainly in the mesomelic segments, a region where SHOX is known to be strongly expressed, offers a possible explanation for the phenotypes seen in patients with FGFR3 (e.g. achondroplasia) and SHOX defects (e.g. LWD). In summary, these data present a link between two frequent short stature phenotypes.
Collapse
Affiliation(s)
- Eva Decker
- Department of Human Molecular Genetics, University of Heidelberg, 69120 Heidelberg, Germany
| | | | | | | | | | | | | | | |
Collapse
|
42
|
Abstract
The transcription factor PU.1 occupies a central role in controlling myeloid and early B-cell development, and its correct lineage-specific expression is critical for the differentiation choice of hematopoietic progenitors. However, little is known of how this tissue-specific pattern is established. We previously identified an upstream regulatory cis element whose targeted deletion in mice decreases PU.1 expression and causes leukemia. We show here that the upstream regulatory cis element alone is insufficient to confer physiologic PU.1 expression in mice but requires the cooperation with other, previously unidentified elements. Using a combination of transgenic studies, global chromatin assays, and detailed molecular analyses we present evidence that PU.1 is regulated by a novel mechanism involving cross talk between different cis elements together with lineage-restricted autoregulation. In this model, PU.1 regulates its expression in B cells and macrophages by differentially associating with cell type-specific transcription factors at one of its cis-regulatory elements to establish differential activity patterns at other elements.
Collapse
|