1
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Short SP, Brown RE, Chen Z, Pilat JM, McElligott BA, Meenderink LM, Bickart AC, Blunt KM, Jacobse J, Wang J, Simmons AJ, Xu Y, Yang Y, Parang B, Choksi YA, Goettel JA, Lau KS, Hiebert SW, Williams CS. MTGR1 is required to maintain small intestinal stem cell populations. Cell Death Differ 2024; 31:1170-1183. [PMID: 39048708 PMCID: PMC11369156 DOI: 10.1038/s41418-024-01346-x] [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: 08/31/2023] [Revised: 07/03/2024] [Accepted: 07/10/2024] [Indexed: 07/27/2024] Open
Abstract
Undifferentiated intestinal stem cells (ISCs) are crucial for maintaining homeostasis and resolving injury. Lgr5+ cells in the crypt base constantly divide, pushing daughter cells upward along the crypt axis where they differentiate into specialized cell types. Coordinated execution of complex transcriptional programs is necessary to allow for the maintenance of undifferentiated stem cells while permitting differentiation of the wide array of intestinal cells necessary for homeostasis. Previously, members of the myeloid translocation gene (MTG) family have been identified as transcriptional co-repressors that regulate stem cell maintenance and differentiation programs in multiple organ systems, including the intestine. One MTG family member, myeloid translocation gene related 1 (MTGR1), has been recognized as a crucial regulator of secretory cell differentiation and response to injury. However, whether MTGR1 contributes to the function of ISCs has not yet been examined. Here, using Mtgr1-/- mice, we have assessed the effects of MTGR1 loss specifically in ISC biology. Interestingly, loss of MTGR1 increased the total number of cells expressing Lgr5, the canonical marker of cycling ISCs, suggesting higher overall stem cell numbers. However, expanded transcriptomic and functional analyses revealed deficiencies in Mtgr1-null ISCs, including deregulated ISC-associated transcriptional programs. Ex vivo, intestinal organoids established from Mtgr1-null mice were unable to survive and expand due to aberrant differentiation and loss of stem and proliferative cells. Together, these results indicate that the role of MTGR1 in intestinal differentiation is likely stem cell intrinsic and identify a novel role for MTGR1 in maintaining ISC function.
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Affiliation(s)
- Sarah P Short
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
- Program in Cancer Biology, Vanderbilt University, Nashville, TN, USA
- Department of Internal Medicine, University of Iowa, Iowa City, IA, USA
| | - Rachel E Brown
- Program in Cancer Biology, Vanderbilt University, Nashville, TN, USA
- Vanderbilt University School of Medicine, Vanderbilt University, Nashville, TN, USA
| | - Zhengyi Chen
- Program in Chemical and Physical Biology, Vanderbilt University, Nashville, TN, USA
- Epithelial Biology Center, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Jennifer M Pilat
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
- Program in Cancer Biology, Vanderbilt University, Nashville, TN, USA
| | | | - Leslie M Meenderink
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
- Veterans Affairs Tennessee Valley Health Care System, Nashville, TN, 37232, USA
| | - Alexander C Bickart
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Koral M Blunt
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
- The Ohio State University College of Medicine, Columbus, OH, USA
| | - Justin Jacobse
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
- Veterans Affairs Tennessee Valley Health Care System, Nashville, TN, 37232, USA
- Willem-Alexander Children's Hospital, Department of Pediatrics, Leiden University Medical Center, Leiden, The Netherlands
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Jing Wang
- Department of Biostatistics, Vanderbilt University, Nashville, TN, USA
- Center for Quantitative Sciences, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Alan J Simmons
- Epithelial Biology Center, Vanderbilt University Medical Center, Nashville, TN, USA
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN, USA
| | - Yanwen Xu
- Epithelial Biology Center, Vanderbilt University Medical Center, Nashville, TN, USA
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN, USA
| | - Yilin Yang
- Epithelial Biology Center, Vanderbilt University Medical Center, Nashville, TN, USA
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN, USA
| | - Bobak Parang
- Program in Cancer Biology, Vanderbilt University, Nashville, TN, USA
- Vanderbilt University School of Medicine, Vanderbilt University, Nashville, TN, USA
- Department of Medicine, Weill Cornell Medicine, New York, NY, 10021, USA
| | - Yash A Choksi
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
- Program in Cancer Biology, Vanderbilt University, Nashville, TN, USA
- Veterans Affairs Tennessee Valley Health Care System, Nashville, TN, 37232, USA
| | - Jeremy A Goettel
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
- Program in Cancer Biology, Vanderbilt University, Nashville, TN, USA
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Ken S Lau
- Epithelial Biology Center, Vanderbilt University Medical Center, Nashville, TN, USA
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN, USA
| | - Scott W Hiebert
- Vanderbilt University School of Medicine, Vanderbilt University, Nashville, TN, USA
- Department of Biochemistry, Vanderbilt University, Nashville, TN, USA
| | - Christopher S Williams
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA.
- Program in Cancer Biology, Vanderbilt University, Nashville, TN, USA.
- Vanderbilt University School of Medicine, Vanderbilt University, Nashville, TN, USA.
- Veterans Affairs Tennessee Valley Health Care System, Nashville, TN, 37232, USA.
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2
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Williams C, Brown R, Zhao Y, Wang J, Chen Z, Blunt K, Pilat J, Parang B, Choksi Y, Lau K, Hiebert S, Short S, Jacobse J, Xu Y, Yang Y, Goettel J. MTGR1 is required to maintain small intestinal stem cell populations. RESEARCH SQUARE 2023:rs.3.rs-3315071. [PMID: 37790452 PMCID: PMC10543309 DOI: 10.21203/rs.3.rs-3315071/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/05/2023]
Abstract
Undifferentiated intestinal stem cells (ISCs), particularly those marked by Lgr5, are crucial for maintaining homeostasis and resolving injury. Lgr5+ cells in the crypt base constantly divide, pushing daughter cells upward along the crypt axis, where they differentiate into a variety of specialized cell types. This process requires coordinated execution of complex transcriptional programs, which allow for the maintenance of undifferentiated stem cells while permitting differentiation of the wide array of intestinal cells necessary for homeostasis. Thus, disrupting these programs may negatively impact homeostasis and response to injury. Previously, members of the myeloid translocation gene (MTG) family have been identified as transcriptional co-repressors that regulate stem cell maintenance and differentiation programs in multiple organ systems, including the intestine. One MTG family member, myeloid translocation gene related 1 (MTGR1), has been recognized as a crucial regulator of secretory cell differentiation and response to injury. However, whether MTGR1 contributes to the function of ISCs has not yet been examined. Here, using Mtgr1-/- mice, we have assessed the effects of MTGR1 loss on ISC biology and differentiation programs. Interestingly, loss of MTGR1 increased the total number of cells expressing Lgr5, the canonical marker of cycling ISCs, suggesting higher overall stem cell numbers. However, expanded transcriptomic analyses revealed MTGR1 loss may instead promote stem cell differentiation into transit-amplifying cells at the expense of cycling ISC populations. Furthermore, ex vivo intestinal organoids established from Mtgr1 null were found nearly completely unable to survive and expand, likely due to aberrant ISC differentiation, suggesting that Mtgr1 null ISCs were functionally deficient as compared to WT ISCs. Together, these results identify a novel role for MTGR1 in ISC function and suggest that MTGR1 is required to maintain the undifferentiated state.
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Affiliation(s)
| | | | | | - Jing Wang
- Vanderbilt University Medical Center
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3
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Brown RE, Jacobse J, Anant SA, Blunt KM, Chen B, Vega PN, Jones CT, Pilat JM, Revetta F, Gorby AH, Stengel KR, Choksi YA, Palin K, Piazuelo MB, Washington MK, Lau KS, Goettel JA, Hiebert SW, Short SP, Williams CS. MTG16 (CBFA2T3) regulates colonic epithelial differentiation, colitis, and tumorigenesis by repressing E protein transcription factors. JCI Insight 2022; 7:153045. [PMID: 35503250 PMCID: PMC9220854 DOI: 10.1172/jci.insight.153045] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Accepted: 04/13/2022] [Indexed: 12/04/2022] Open
Abstract
Aberrant epithelial differentiation and regeneration contribute to colon pathologies including inflammatory bowel disease (IBD) and colitis-associated cancer (CAC). MTG16 (CBFA2T3) is a transcriptional corepressor expressed in the colonic epithelium. MTG16 deficiency in mice exacerbates colitis and increases tumor burden in CAC, though the underlying mechanisms remain unclear. Here, we identified MTG16 as a central mediator of epithelial differentiation, promoting goblet and restraining enteroendocrine cell development in homeostasis and enabling regeneration following dextran sulfate sodium (DSS)-induced colitis. Transcriptomic analyses implicated increased E box-binding transcription factor (E protein) activity in MTG16-deficient colon crypts. Using a novel mouse model with a point mutation that attenuates MTG16:E protein interactions (Mtg16P209T), we established that MTG16 exerts control over colonic epithelial differentiation and regeneration by repressing E protein-mediated transcription. Mimicking murine colitis, MTG16 expression was increased in biopsies from patients with active IBD compared to unaffected controls. Finally, uncoupling MTG16:E protein interactions partially phenocopied the enhanced tumorigenicity of Mtg16-/- colon in the azoxymethane(AOM)/DSS-induced model of CAC, indicating that MTG16 protects from tumorigenesis through additional mechanisms. Collectively, our results demonstrate that MTG16, via its repression of E protein targets, is a key regulator of cell fate decisions during colon homeostasis, colitis, and cancer.
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Affiliation(s)
- Rachel E Brown
- Program in Cancer Biology, Vanderbilt University School of Medicine, Nashville, United States of America
| | - Justin Jacobse
- Willem-Alexander Children's Hospital, Leiden University Medical Center, Leiden, Netherlands
| | - Shruti A Anant
- Department of Medicine, Health, and Society, Vanderbilt University, Nashville, United States of America
| | - Koral M Blunt
- Department of Medicine, Vanderbilt University Medical Center, Nashville, United States of America
| | - Bob Chen
- Program in Chemical and Physical Biology, Vanderbilt University School of Medicine, Nashville, United States of America
| | - Paige N Vega
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, United States of America
| | - Chase T Jones
- Department of Medicine, Vanderbilt University Medical Center, Nashville, United States of America
| | - Jennifer M Pilat
- Program in Cancer Biology, Vanderbilt University School of Medicine, Nashville, United States of America
| | - Frank Revetta
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University, Nashville, United States of America
| | - Aidan H Gorby
- Department of Medicine, Vanderbilt University Medical Center, Nashville, United States of America
| | - Kristy R Stengel
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, United States of America
| | - Yash A Choksi
- Department of Medicine, Vanderbilt University Medical Center, Nashville, United States of America
| | - Kimmo Palin
- Department of Medical and Clinical Genetics, University of Helsinki, Helsinki, Finland
| | - M Blanca Piazuelo
- Department of Medicine, Vanderbilt University Medical Center, Nashville, United States of America
| | - Mary K Washington
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University, Nashville, United States of America
| | - Ken S Lau
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, United States of America
| | - Jeremy A Goettel
- Department of Medicine, Vanderbilt University Medical Center, Nashville, United States of America
| | - Scott W Hiebert
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, United States of America
| | - Sarah P Short
- Department of Medicine, Vanderbilt University Medical Center, Nashville, United States of America
| | - Christopher S Williams
- Department of Medicine, Vanderbilt University Medical Center, Nashville, United States of America
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4
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Abou Azar F, Lim GE. Metabolic Contributions of Wnt Signaling: More Than Controlling Flight. Front Cell Dev Biol 2021; 9:709823. [PMID: 34568323 PMCID: PMC8458764 DOI: 10.3389/fcell.2021.709823] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Accepted: 08/16/2021] [Indexed: 12/12/2022] Open
Abstract
The canonical Wnt signaling pathway is ubiquitous throughout the body and influences a diverse array of physiological processes. Following the initial discovery of the Wnt signaling pathway during wing development in Drosophila melanogaster, it is now widely appreciated that active Wnt signaling in mammals is necessary for the development and growth of various tissues involved in whole-body metabolism, such as brain, liver, pancreas, muscle, and adipose. Moreover, elegant gain- and loss-of-function studies have dissected the tissue-specific roles of various downstream effector molecules in the regulation of energy homeostasis. This review attempts to highlight and summarize the contributions of the Wnt signaling pathway and its downstream effectors on whole-body metabolism and their influence on the development of metabolic diseases, such as diabetes and obesity. A better understanding of the Wnt signaling pathway in these tissues may aid in guiding the development of future therapeutics to treat metabolic diseases.
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Affiliation(s)
- Frederic Abou Azar
- Department of Medicine, Université de Montréal, Montreal, QC, Canada.,Cardiometabolic Axis, Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montreal, QC, Canada
| | - Gareth E Lim
- Department of Medicine, Université de Montréal, Montreal, QC, Canada.,Cardiometabolic Axis, Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montreal, QC, Canada
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Papathanasiou M, Tsiftsoglou SA, Polyzos AP, Papadopoulou D, Valakos D, Klagkou E, Karagianni P, Pliatska M, Talianidis I, Agelopoulos M, Thanos D. Identification of a dynamic gene regulatory network required for pluripotency factor-induced reprogramming of mouse fibroblasts and hepatocytes. EMBO J 2021; 40:e102236. [PMID: 33034061 PMCID: PMC7780151 DOI: 10.15252/embj.2019102236] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Revised: 08/27/2020] [Accepted: 09/07/2020] [Indexed: 01/04/2023] Open
Abstract
The generation of induced pluripotent stem cells (iPSCs) from somatic cells provides an excellent model to study mechanisms of transcription factor-induced global alterations of the epigenome and genome function. Here, we have investigated the early transcriptional events of cellular reprogramming triggered by the co-expression of Oct4, Sox2, Klf4, and c-Myc (OSKM) in mouse embryonic fibroblasts (MEFs) and mouse hepatocytes (mHeps). In this analysis, we identified a gene regulatory network composed of nine transcriptional regulators (9TR; Cbfa2t3, Gli2, Irf6, Nanog, Ovol1, Rcan1, Taf1c, Tead4, and Tfap4), which are directly targeted by OSKM, in vivo. Functional studies using single and double shRNA knockdowns of any of these factors caused disruption of the network and dramatic reductions in reprogramming efficiency, indicating that this network is essential for the induction and establishment of pluripotency. We demonstrate that the stochastic co-expression of 9TR network components occurs in a remarkably small number of cells, approximating the percentage of terminally reprogrammed cells as a result of dynamic molecular events. Thus, the early DNA-binding patterns of OSKM and the subsequent probabilistic co-expression of essential 9TR components in subpopulations of cells undergoing reprogramming steer the reconstruction of a gene regulatory network marking the transition to pluripotency.
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Affiliation(s)
| | | | | | | | | | | | | | - Maria Pliatska
- Biomedical Research Foundation Academy of AthensAthensGreece
| | | | | | - Dimitris Thanos
- Biomedical Research Foundation Academy of AthensAthensGreece
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6
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Baulies A, Angelis N, Foglizzo V, Danielsen ET, Patel H, Novellasdemunt L, Kucharska A, Carvalho J, Nye E, De Coppi P, Li VS. The Transcription Co-Repressors MTG8 and MTG16 Regulate Exit of Intestinal Stem Cells From Their Niche and Differentiation Into Enterocyte vs Secretory Lineages. Gastroenterology 2020; 159:1328-1341.e3. [PMID: 32553763 PMCID: PMC7607384 DOI: 10.1053/j.gastro.2020.06.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Revised: 05/07/2020] [Accepted: 06/04/2020] [Indexed: 12/17/2022]
Abstract
BACKGROUND & AIMS Notch signaling maintains intestinal stem cells (ISCs). When ISCs exit the niche, Notch signaling among early progenitor cells at position +4/5 regulates their specification toward secretory vs enterocyte lineages (binary fate). The transcription factor ATOH1 is repressed by Notch in ISCs; its de-repression, when Notch is inactivated, drives progenitor cells to differentiate along the secretory lineage. However, it is not clear what promotes transition of ISCs to progenitors and how this fate decision is established. METHODS We sorted cells from Lgr5-GFP knockin intestines from mice and characterized gene expression patterns. We analyzed Notch regulation by examining expression profiles (by quantitative reverse transcription polymerase chain reaction and RNAscope) of small intestinal organoids incubated with the Notch inhibitor DAPT, intestine tissues from mice given injections of the γ-secretase inhibitor dibenzazepine, and mice with intestine-specific disruption of Rbpj. We analyzed intestine tissues from mice with disruption of the RUNX1 translocation partner 1 gene (Runx1t1, also called Mtg8) or CBFA2/RUNX1 partner transcriptional co-repressor 3 (Cbfa2t3, also called Mtg16), and derived their organoids, by histology, immunohistochemistry, and RNA sequencing (RNA-seq). We performed chromatin immunoprecipitation and sequencing analyses of intestinal crypts to identify genes regulated by MTG16. RESULTS The transcription co-repressors MTG8 and MTG16 were highly expressed by +4/5 early progenitors, compared with other cells along crypt-villus axis. Expression of MTG8 and MTG16 were repressed by Notch signaling via ATOH1 in organoids and intestine tissues from mice. MTG8- and MTG16-knockout intestines had increased crypt hyperproliferation and expansion of ISCs, but enterocyte differentiation was impaired, based on loss of enterocyte markers and functions. Chromatin immunoprecipitation and sequencing analyses showed that MTG16 bound to promoters of genes that are specifically expressed by stem cells (such as Lgr5 and Ascl2) and repressed their transcription. MTG16 also bound to previously reported enhancer regions of genes regulated by ATOH1, including genes that encode Delta-like canonical Notch ligand and other secretory-specific transcription factors. CONCLUSIONS In intestine tissues of mice and human intestinal organoids, MTG8 and MTG16 repress transcription in the earliest progenitor cells to promote exit of ISCs from their niche (niche exit) and control the binary fate decision (secretory vs enterocyte lineage) by repressing genes regulated by ATOH1.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Emma Nye
- The Francis Crick Institute, London, UK
| | - Paolo De Coppi
- Department of Paediatric Surgery, UCL Great Ormond Street Institute of Child Health and Great Ormond Street Hospital for Children, London, UK
| | - Vivian S.W. Li
- The Francis Crick Institute, London, UK,Correspondence Address correspondence to: Vivian Li, PhD, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK.
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7
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Habowski AN, Flesher JL, Bates JM, Tsai CF, Martin K, Zhao R, Ganesan AK, Edwards RA, Shi T, Wiley HS, Shi Y, Hertel KJ, Waterman ML. Transcriptomic and proteomic signatures of stemness and differentiation in the colon crypt. Commun Biol 2020; 3:453. [PMID: 32814826 PMCID: PMC7438495 DOI: 10.1038/s42003-020-01181-z] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Accepted: 07/16/2020] [Indexed: 02/07/2023] Open
Abstract
Intestinal stem cells are non-quiescent, dividing epithelial cells that rapidly differentiate into progenitor cells of the absorptive and secretory cell lineages. The kinetics of this process is rapid such that the epithelium is replaced weekly. To determine how the transcriptome and proteome keep pace with rapid differentiation, we developed a new cell sorting method to purify mouse colon epithelial cells. Here we show that alternative mRNA splicing and polyadenylation dominate changes in the transcriptome as stem cells differentiate into progenitors. In contrast, as progenitors differentiate into mature cell types, changes in mRNA levels dominate the transcriptome. RNA processing targets regulators of cell cycle, RNA, cell adhesion, SUMOylation, and Wnt and Notch signaling. Additionally, global proteome profiling detected >2,800 proteins and revealed RNA:protein patterns of abundance and correlation. Paired together, these data highlight new potentials for autocrine and feedback regulation and provide new insights into cell state transitions in the crypt.
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Affiliation(s)
- Amber N Habowski
- Department of Microbiology and Molecular Genetics, University of California Irvine, Irvine, CA, 92697, USA
| | - Jessica L Flesher
- Department of Biological Chemistry, University of California Irvine, Irvine, CA, 92697, USA
| | - Jennifer M Bates
- Institute for Immunology, University of California Irvine, Irvine, CA, 92697, USA
| | - Chia-Feng Tsai
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA, 99354, USA
| | - Kendall Martin
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA, 99354, USA
| | - Rui Zhao
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA, 99354, USA
| | - Anand K Ganesan
- Department of Biological Chemistry, University of California Irvine, Irvine, CA, 92697, USA
- Department of Dermatology, University of California Irvine, Irvine, CA, 92697, USA
| | - Robert A Edwards
- Department of Pathology and Laboratory Medicine, University of California Irvine, Irvine, CA, 92697, USA
| | - Tujin Shi
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA, 99354, USA
| | - H Steven Wiley
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA, 99354, USA
| | - Yongsheng Shi
- Department of Microbiology and Molecular Genetics, University of California Irvine, Irvine, CA, 92697, USA
| | - Klemens J Hertel
- Department of Microbiology and Molecular Genetics, University of California Irvine, Irvine, CA, 92697, USA
| | - Marian L Waterman
- Department of Microbiology and Molecular Genetics, University of California Irvine, Irvine, CA, 92697, USA.
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8
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Altıner Ş, Yürür Kutlay N, Ilgın Ruhi H. Mosaic Small Supernumerary Marker Chromosome Derived from Five Discontinuous Regions of Chromosome 8 in a Patient with Neutropenia and Oral Aphthous Ulcer. Cytogenet Genome Res 2020; 160:11-17. [PMID: 31982875 DOI: 10.1159/000505805] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/06/2019] [Indexed: 11/19/2022] Open
Abstract
Small supernumerary marker chromosomes (sSMCs) are characterized as additional centric chromosome fragments which are too small to be classified by cytogenetic banding alone and smaller than or equal to the size of chromosome 20 of the same metaphase spread. Here, we report a patient who presented with slight neutropenia and oral aphthous ulcers. A mosaic de novo sSMC, which originated from 5 discontinuous regions of chromosome 8, was detected in the patient. Formation of the sSMC(8) can probably be explained by a multi-step process beginning with maternal meiotic nondisjunction, followed by post-zygotic anaphase lag, and resulting in chromothripsis. Chromothripsis is a chromosomal rearrangement which occurs by breakage of one or more chromosomes leading to a fusion of surviving chromosome pieces. This case is a good example for emphasizing the importance of conventional karyotyping from PHA-induced peripheral blood lymphocytes and examining tissues other than bone marrow in patients with inconsistent genotype and phenotype.
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9
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Shadrin AA, Smeland OB, Zayats T, Schork AJ, Frei O, Bettella F, Witoelar A, Li W, Eriksen JA, Krull F, Djurovic S, Faraone SV, Reichborn-Kjennerud T, Thompson WK, Johansson S, Haavik J, Dale AM, Wang Y, Andreassen OA. Novel Loci Associated With Attention-Deficit/Hyperactivity Disorder Are Revealed by Leveraging Polygenic Overlap With Educational Attainment. J Am Acad Child Adolesc Psychiatry 2018; 57:86-95. [PMID: 29413154 PMCID: PMC5806128 DOI: 10.1016/j.jaac.2017.11.013] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Revised: 11/11/2017] [Accepted: 11/21/2017] [Indexed: 01/08/2023]
Abstract
OBJECTIVE Attention-deficit/hyperactivity disorder (ADHD) is a common and highly heritable psychiatric condition. By exploiting the reported relationship between ADHD and educational attainment (EA), we aimed to improve discovery of ADHD-associated genetic variants and to investigate genetic overlap between these phenotypes. METHOD A conditional/conjunctional false discovery rate (condFDR/conjFDR) method was applied to genome-wide association study (GWAS) data on ADHD (2,064 trios, 896 cases, and 2,455 controls) and EA (n=328,917) to identify ADHD-associated loci and loci overlapping between ADHD and EA. Identified single nucleotide polymorphisms (SNPs) were tested for association in an independent population-based study of ADHD symptoms (n=17,666). Genetic correlation between ADHD and EA was estimated using LD score regression and Pearson correlation. RESULTS At levels of condFDR<0.01 and conjFDR<0.05, we identified 5 ADHD-associated loci, 3 of these being shared between ADHD and EA. None of these loci had been identified in the primary ADHD GWAS, demonstrating the increased power provided by the condFDR/conjFDR analysis. Leading SNPs for 4 of 5 identified regions are in introns of protein coding genes (KDM4A, MEF2C, PINK1, RUNX1T1), whereas the remaining one is an intergenic SNP on chromosome 2 at 2p24. Consistent direction of effects in the independent study of ADHD symptoms was shown for 4 of 5 identified loci. A polygenic overlap between ADHD and EA was supported by significant genetic correlation (rg=-0.403, p=7.90×10-8) and >10-fold mutual enrichment of SNPs associated with both traits. CONCLUSION We identified 5 novel loci associated with ADHD and provided evidence for a shared genetic basis between ADHD and EA. These findings could aid understanding of the genetic risk architecture of ADHD and its relation to EA.
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Affiliation(s)
- Alexey A Shadrin
- NORMENT, KG Jebsen Centre for Psychosis Research, Institute of Clinical Medicine, University of Oslo, Oslo, Norway and Division of Mental Health and Addiction, Oslo University Hospital, Oslo, Norway.
| | - Olav B Smeland
- NORMENT, KG Jebsen Centre for Psychosis Research, Institute of Clinical Medicine, University of Oslo, Oslo, Norway and Division of Mental Health and Addiction, Oslo University Hospital, Oslo, Norway
| | - Tetyana Zayats
- K.G. Jebsen Centre for Neuropsychiatric Disorders, University of Bergen, Bergen, Norway
| | - Andrew J Schork
- University of California, San Diego and Institute of Biological Psychiatry, Medical Health Center, Sct. Hans Hospital and University of Copenhagen, Copenhagen, Denmark
| | - Oleksandr Frei
- NORMENT, KG Jebsen Centre for Psychosis Research, Institute of Clinical Medicine, University of Oslo, Oslo, Norway and Division of Mental Health and Addiction, Oslo University Hospital, Oslo, Norway
| | - Francesco Bettella
- NORMENT, KG Jebsen Centre for Psychosis Research, Institute of Clinical Medicine, University of Oslo, Oslo, Norway and Division of Mental Health and Addiction, Oslo University Hospital, Oslo, Norway
| | - Aree Witoelar
- NORMENT, KG Jebsen Centre for Psychosis Research, Institute of Clinical Medicine, University of Oslo, Oslo, Norway and Division of Mental Health and Addiction, Oslo University Hospital, Oslo, Norway
| | - Wen Li
- NORMENT, KG Jebsen Centre for Psychosis Research, Institute of Clinical Medicine, University of Oslo, Oslo, Norway and Division of Mental Health and Addiction, Oslo University Hospital, Oslo, Norway
| | - Jon A Eriksen
- NORMENT, KG Jebsen Centre for Psychosis Research, Institute of Clinical Medicine, University of Oslo, Oslo, Norway and Division of Mental Health and Addiction, Oslo University Hospital, Oslo, Norway
| | - Florian Krull
- NORMENT, KG Jebsen Centre for Psychosis Research, Institute of Clinical Medicine, University of Oslo, Oslo, Norway and Division of Mental Health and Addiction, Oslo University Hospital, Oslo, Norway
| | - Srdjan Djurovic
- Oslo University Hospital, Oslo, and NORMENT, KG Jebsen Centre for Psychosis Research, University of Bergen
| | - Stephen V Faraone
- KG Jebsen Centre for Neuropsychiatric Disorders, University of Bergen, SUNY Upstate Medical University, Syracuse, New York
| | - Ted Reichborn-Kjennerud
- Division of Mental Health, Norwegian Institute of Public Health, Oslo, and Institute of Clinical Medicine, University of Oslo
| | | | - Stefan Johansson
- K.G. Jebsen Centre for Neuropsychiatric Disorders, University of Bergen, Bergen, Norway; Center for Medical Genetics and Molecular Medicine, Haukeland University Hospital, Bergen, Norway
| | - Jan Haavik
- K.G. Jebsen Centre for Neuropsychiatric Disorders, University of Bergen, Bergen, Norway; Division of Psychiatry, Haukeland University Hospital
| | - Anders M Dale
- NORMENT, KG Jebsen Centre for Psychosis Research, Institute of Clinical Medicine, University of Oslo, and University of California, San Diego
| | - Yunpeng Wang
- NORMENT, KG Jebsen Centre for Psychosis Research, Institute of Clinical Medicine, University of Oslo, Oslo, Norway and Division of Mental Health and Addiction, Oslo University Hospital, Oslo, Norway; University of California, San Diego, La Jolla, CA
| | - Ole A Andreassen
- NORMENT, KG Jebsen Centre for Psychosis Research, Institute of Clinical Medicine, University of Oslo, Oslo, Norway and Division of Mental Health and Addiction, Oslo University Hospital, Oslo, Norway
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10
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Emerging Roles of MTG16 in Cell-Fate Control of Hematopoietic Stem Cells and Cancer. Stem Cells Int 2017; 2017:6301385. [PMID: 29358956 PMCID: PMC5735743 DOI: 10.1155/2017/6301385] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2017] [Revised: 10/12/2017] [Accepted: 10/23/2017] [Indexed: 12/13/2022] Open
Abstract
MTG16 (myeloid translocation gene on chromosome 16) and its related proteins, MTG8 and MTGR1, define a small family of transcriptional corepressors. These corepressors share highly conserved domain structures yet have distinct biological functions and tissue specificity. In vivo studies have shown that, of the three MTG corepressors, MTG16 is uniquely important for the regulation of hematopoietic stem/progenitor cell (HSPC) proliferation and differentiation. Apart from this physiological function, MTG16 is also involved in carcinomas and leukemias, acting as the genetic target of loss of heterozygosity (LOH) aberrations in breast cancer and recurrent translocations in leukemia. The frequent involvement of MTG16 in these disease etiologies implies an important developmental role for this transcriptional corepressor. Furthermore, mounting evidence suggests that MTG16 indirectly alters the disease course of several leukemias via its regulatory interactions with a variety of pathologic fusion proteins. For example, a recent study has shown that MTG16 can repress not only wild-type E2A-mediated transcription, but also leukemia fusion protein E2A-Pbx1-mediated transcription, suggesting that MTG16 may serve as a potential therapeutic target in acute lymphoblastic leukemia expressing the E2A-Pbx1 fusion protein. Given that leukemia stem cells share similar regulatory pathways with normal HSPCs, studies to further understand how MTG16 regulates cell proliferation and differentiation could lead to novel therapeutic approaches for leukemia treatment.
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11
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McDonough EM, Barrett CW, Parang B, Mittal MK, Smith JJ, Bradley AM, Choksi YA, Coburn LA, Short SP, Thompson JJ, Zhang B, Poindexter SV, Fischer MA, Chen X, Li J, Revetta FL, Naik R, Washington MK, Rosen MJ, Hiebert SW, Wilson KT, Williams CS. MTG16 is a tumor suppressor in colitis-associated carcinoma. JCI Insight 2017; 2:78210. [PMID: 28814670 DOI: 10.1172/jci.insight.78210] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Accepted: 07/14/2017] [Indexed: 12/27/2022] Open
Abstract
MTG16 is a member of the myeloid translocation gene (MTG) family of transcriptional corepressors. While MTGs were originally identified in chromosomal translocations in acute myeloid leukemia, recent studies have uncovered a role in intestinal biology. For example, Mtg16-/- mice have increased intestinal proliferation and are more sensitive to intestinal injury in colitis models. MTG16 is also underexpressed in patients with moderate/severe ulcerative colitis. Based on these findings, we postulated that MTG16 might protect against colitis-associated carcinogenesis. MTG16 was downregulated at the protein and RNA levels in patients with inflammatory bowel disease and in those with colitis-associated carcinoma. Mtg16-/- mice subjected to inflammatory carcinogenesis modeling exhibited worse colitis and increased tumor multiplicity and size. Loss of MTG16 also increased severity of dysplasia, apoptosis, proliferation, DNA damage, and WNT signaling. Moreover, transplantation of WT marrow into Mtg16-/- mice failed to rescue the Mtg16-/- protumorigenic phenotypes, indicating an epithelium-specific role for MTG16. While MTG dysfunction is widely appreciated in hematopoietic malignancies, the role of this gene family in epithelial homeostasis, and in colon cancer, was unrealized. This report identifies MTG16 as an important modulator of colitis and tumor development in inflammatory carcinogenesis.
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Affiliation(s)
| | | | | | | | | | | | - Yash A Choksi
- Department of Medicine, Division of Gastroenterology
| | - Lori A Coburn
- Department of Medicine, Division of Gastroenterology.,Veterans Affairs Tennessee Valley Healthcare System, Nashville, Tennessee, USA
| | | | | | | | | | - Melissa A Fischer
- Department of Biochemistry, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Xi Chen
- Department of Public Health Sciences and the Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, Florida, USA
| | - Jiang Li
- Program in Epithelial Biology, Stanford University School of Medicine, Stanford, California, USA
| | - Frank L Revetta
- Department of Pathology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Rishi Naik
- Department of Cancer Biology.,Department of Medicine, Division of Gastroenterology
| | - M Kay Washington
- Department of Pathology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Michael J Rosen
- Division of Gastroenterology, Hepatology and Nutrition, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - Scott W Hiebert
- Department of Biochemistry, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Keith T Wilson
- Department of Cancer Biology.,Department of Medicine, Division of Gastroenterology.,Veterans Affairs Tennessee Valley Healthcare System, Nashville, Tennessee, USA.,Vanderbilt-Ingram Cancer Center, Nashville, Tennessee, USA
| | - Christopher S Williams
- Department of Cancer Biology.,Department of Medicine, Division of Gastroenterology.,Veterans Affairs Tennessee Valley Healthcare System, Nashville, Tennessee, USA.,Vanderbilt-Ingram Cancer Center, Nashville, Tennessee, USA
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12
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Parang B, Bradley AM, Mittal MK, Short SP, Thompson JJ, Barrett CW, Naik RD, Bilotta AJ, Washington MK, Revetta FL, Smith JJ, Chen X, Wilson KT, Hiebert SW, Williams CS. Myeloid translocation genes differentially regulate colorectal cancer programs. Oncogene 2016; 35:6341-6349. [PMID: 27270437 PMCID: PMC5140770 DOI: 10.1038/onc.2016.167] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2015] [Revised: 03/02/2016] [Accepted: 04/08/2016] [Indexed: 12/11/2022]
Abstract
Myeloid translocation genes (MTGs), originally identified as chromosomal translocations in acute myelogenous leukemia, are transcriptional corepressors that regulate hematopoietic stem cell programs. Analysis of The Cancer Genome Atlas (TCGA) database revealed that MTGs were mutated in epithelial malignancy and suggested that loss of function might promote tumorigenesis. Genetic deletion of MTGR1 and MTG16 in the mouse has revealed unexpected and unique roles within the intestinal epithelium. Mtgr1−/− mice have progressive depletion of all intestinal secretory cells, and Mtg16−/− mice have a decrease in goblet cells. Furthermore, both Mtgr1−/− and Mtg16−/− mice have increased intestinal epithelial cell proliferation. We thus hypothesized that loss of MTGR1 or MTG16 would modify Apc1638/+-dependent intestinal tumorigenesis. Mtgr1−/− mice, but not Mtg16−/− mice, had a 10-fold increase in tumor multiplicity. This was associated with more advanced dysplasia, including progression to invasive adenocarcinoma, and augmented intratumoral proliferation. Analysis of ChIP-seq datasets for MTGR1 and MTG16 targets indicated that MTGR1 can regulate Wnt and Notch signaling. In support of this, immunohistochemistry and gene expression analysis revealed that both Wnt and Notch signaling pathways were hyperactive in Mtgr1−/− tumors. Furthermore, in human colorectal cancer (CRC) samples MTGR1 was downregulated at both the transcript and protein level. Overall our data indicates that MTGR1 has a context dependent effect on intestinal tumorigenesis.
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Affiliation(s)
- B Parang
- Department of Medicine, Division of Gastroenterology, Vanderbilt University School of Medicine, Nashville, TN, USA.,Department of Cancer Biology, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - A M Bradley
- Department of Medicine, Division of Gastroenterology, Vanderbilt University School of Medicine, Nashville, TN, USA.,Department of Cancer Biology, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - M K Mittal
- Department of Medicine, Division of Gastroenterology, Vanderbilt University School of Medicine, Nashville, TN, USA.,Department of Cancer Biology, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - S P Short
- Department of Medicine, Division of Gastroenterology, Vanderbilt University School of Medicine, Nashville, TN, USA.,Department of Cancer Biology, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - J J Thompson
- Department of Medicine, Division of Gastroenterology, Vanderbilt University School of Medicine, Nashville, TN, USA.,Department of Cancer Biology, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - C W Barrett
- Department of Medicine, Division of Gastroenterology, Vanderbilt University School of Medicine, Nashville, TN, USA.,Department of Cancer Biology, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - R D Naik
- Department of Medicine, Division of Gastroenterology, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - A J Bilotta
- Department of Medicine, Division of Gastroenterology, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - M K Washington
- Department of Pathology, Microbiology, and Immunology, Nashville, TN, USA
| | - F L Revetta
- Department of Pathology, Microbiology, and Immunology, Nashville, TN, USA
| | - J J Smith
- Department of Surgery, Division of Surgical Oncology, Nashville, TN, USA
| | - X Chen
- Department of Biostatistics, Nashville, TN, USA
| | - K T Wilson
- Department of Medicine, Division of Gastroenterology, Vanderbilt University School of Medicine, Nashville, TN, USA.,Department of Cancer Biology, Vanderbilt University School of Medicine, Nashville, TN, USA.,Vanderbilt Ingram Cancer Center, Nashville, TN, USA.,Veterans Affairs Tennessee Valley Health Care System, Nashville, TN, USA
| | - S W Hiebert
- Vanderbilt Ingram Cancer Center, Nashville, TN, USA.,Department of Biochemistry, Nashville, TN, USA
| | - C S Williams
- Department of Medicine, Division of Gastroenterology, Vanderbilt University School of Medicine, Nashville, TN, USA.,Department of Cancer Biology, Vanderbilt University School of Medicine, Nashville, TN, USA.,Vanderbilt Ingram Cancer Center, Nashville, TN, USA.,Veterans Affairs Tennessee Valley Health Care System, Nashville, TN, USA
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13
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SUMOylation Regulates Growth Factor Independence 1 in Transcriptional Control and Hematopoiesis. Mol Cell Biol 2016; 36:1438-50. [PMID: 26951200 DOI: 10.1128/mcb.01001-15] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Accepted: 02/20/2016] [Indexed: 01/08/2023] Open
Abstract
Cell fate specification requires precise coordination of transcription factors and their regulators to achieve fidelity and flexibility in lineage allocation. The transcriptional repressor growth factor independence 1 (GFI1) is comprised of conserved Snail/Slug/Gfi1 (SNAG) and zinc finger motifs separated by a linker region poorly conserved with GFI1B, its closest homolog. Moreover, GFI1 and GFI1B coordinate distinct developmental fates in hematopoiesis, suggesting that their functional differences may derive from structures within their linkers. We show a binding interface between the GFI1 linker and the SP-RING domain of PIAS3, an E3-SUMO (small ubiquitin-related modifier) ligase. The PIAS3 binding region in GFI1 contains a conserved type I SUMOylation consensus element, centered on lysine-239 (K239). In silico prediction algorithms identify K239 as the only high-probability site for SUMO modification. We show that GFI1 is modified by SUMO at K239. SUMOylation-resistant derivatives of GFI1 fail to complement Gfi1 depletion phenotypes in zebrafish primitive erythropoiesis and granulocytic differentiation in cultured human cells. LSD1/CoREST recruitment and MYC repression by GFI1 are profoundly impaired for SUMOylation-resistant GFI1 derivatives, while enforced expression of MYC blocks granulocytic differentiation. These findings suggest that SUMOylation within the GFI1 linker favors LSD1/CoREST recruitment and MYC repression to govern hematopoietic differentiation.
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14
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Dunn SJ, Osborne JM, Appleton PL, Näthke I. Combined changes in Wnt signaling response and contact inhibition induce altered proliferation in radiation-treated intestinal crypts. Mol Biol Cell 2016; 27:1863-74. [PMID: 27053661 PMCID: PMC4884076 DOI: 10.1091/mbc.e15-12-0854] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Accepted: 03/30/2016] [Indexed: 12/15/2022] Open
Abstract
Wnt concentration gradients operate in many tissues. Modeling of proliferation in control and irradiated intestinal crypts shows that the Wnt concentrations that cells experience when they are born set their proliferative fate and cell cycle duration. The simulations also predict the initial proportion of cells damaged by tumor-promoting radiation. Curative intervention is possible if colorectal cancer is identified early, underscoring the need to detect the earliest stages of malignant transformation. A candidate biomarker is the expanded proliferative zone observed in crypts before adenoma formation, also found in irradiated crypts. However, the underlying driving mechanism for this is not known. Wnt signaling is a key regulator of proliferation, and elevated Wnt signaling is implicated in cancer. Nonetheless, how cells differentiate Wnt signals of varying strengths is not understood. We use computational modeling to compare alternative hypotheses about how Wnt signaling and contact inhibition affect proliferation. Direct comparison of simulations with published experimental data revealed that the model that best reproduces proliferation patterns in normal crypts stipulates that proliferative fate and cell cycle duration are set by the Wnt stimulus experienced at birth. The model also showed that the broadened proliferation zone induced by tumorigenic radiation can be attributed to cells responding to lower Wnt concentrations and dividing at smaller volumes. Application of the model to data from irradiated crypts after an extended recovery period permitted deductions about the extent of the initial insult. Application of computational modeling to experimental data revealed how mechanisms that control cell dynamics are altered at the earliest stages of carcinogenesis.
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Affiliation(s)
- S-J Dunn
- Microsoft Research, Cambridge CB1 3LS, United Kingdom
| | - J M Osborne
- School of Mathematics and Statistics, University of Melbourne, Melbourne, VIC 3010, Australia
| | - P L Appleton
- Division of Cell and Developmental Biology, University of Dundee, Dundee DD1 5EH, United Kingdom
| | - I Näthke
- Division of Cell and Developmental Biology, University of Dundee, Dundee DD1 5EH, United Kingdom
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15
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Sánchez-Tilló E, de Barrios O, Valls E, Darling DS, Castells A, Postigo A. ZEB1 and TCF4 reciprocally modulate their transcriptional activities to regulate Wnt target gene expression. Oncogene 2015; 34:5760-70. [PMID: 26387539 DOI: 10.1038/onc.2015.352] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Revised: 07/27/2015] [Accepted: 08/14/2015] [Indexed: 12/21/2022]
Abstract
The canonical Wnt pathway (TCF4/β-catenin) has important roles during normal differentiation and in disease. Some Wnt functions depend on signaling gradients requiring the pathway to be tightly regulated. A key Wnt target is the transcription factor ZEB1 whose expression by cancer cells promotes tumor invasiveness by repressing the expression of epithelial specification markers and activating mesenchymal genes, including a number of Wnt targets such as LAMC2 and uPA. The ability of ZEB1 to activate/repress its target genes depends on its recruitment of corepressors (CtBP, BRG1) or coactivators (p300) although conditions under which ZEB1 binds these cofactors are not elucidated. Here, we show that TCF4 and ZEB1 reciprocally modulate each other's transcriptional activity: ZEB1 enhances TCF4/β-catenin-mediated transcription and, in turn, Wnt signaling switches ZEB1 from a repressor into an activator. In colorectal cancer (CRC) cells with active Wnt signaling, ZEB1 enhances transcriptional activation of LAMC2 and uPA by TCF4/β-catenin. However, in CRC cells with inactive Wnt, ZEB1 represses both genes. Reciprocal modulation of ZEB1 and TCF4 activities involves their binding to DNA and mutual interaction. Wnt signaling turns ZEB1 into an activator by replacing binding of CtBP/BRG1 in favor of p300. Using a mouse model of Wnt-induced intestinal tumorigenesis, we found that downregulation of ZEB1 reduces the expression of LAMC2 in vivo. These results identify a mechanism through which Wnt and ZEB1 transcriptional activities are modulated, offering new approaches in cancer therapy.
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Affiliation(s)
- E Sánchez-Tilló
- Group of Transcriptional Regulation of Gene Expression, Department of Oncology and Hematology, IDIBAPS, Barcelona, Spain
| | - O de Barrios
- Group of Transcriptional Regulation of Gene Expression, Department of Oncology and Hematology, IDIBAPS, Barcelona, Spain
| | - E Valls
- Group of Transcriptional Regulation of Gene Expression, Department of Oncology and Hematology, IDIBAPS, Barcelona, Spain
| | - D S Darling
- Department of Oral Immunology and Infectious Diseases and Center for Genetics and Molecular Medicine, University of Louisville, Louisville, KY, USA
| | - A Castells
- Institute of Metabolic and Digestive Diseases, Hospital Clinic, Barcelona, Spain.,Gastrointestinal and Pancreatic Oncology Team, Biomedical Research Networking Centers in Hepatic and Digestive Diseases (CIBERehd), Carlos III Health Institute (ISCIII), Barcelona, Spain
| | - A Postigo
- Group of Transcriptional Regulation of Gene Expression, Department of Oncology and Hematology, IDIBAPS, Barcelona, Spain.,Gastrointestinal and Pancreatic Oncology Team, Biomedical Research Networking Centers in Hepatic and Digestive Diseases (CIBERehd), Carlos III Health Institute (ISCIII), Barcelona, Spain.,James Graham Brown Cancer Center, Louisville, KY, USA.,ICREA, Barcelona, Spain
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16
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Poindexter SV, Reddy VK, Mittal MK, Williams AM, Washington MK, Harris E, Mah A, Hiebert SW, Singh K, Chaturvedi R, Wilson KT, Lund PK, Williams CS. Transcriptional corepressor MTG16 regulates small intestinal crypt proliferation and crypt regeneration after radiation-induced injury. Am J Physiol Gastrointest Liver Physiol 2015; 308:G562-71. [PMID: 25573176 PMCID: PMC4360050 DOI: 10.1152/ajpgi.00253.2014] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Myeloid translocation genes (MTGs) are transcriptional corepressors implicated in development, malignancy, differentiation, and stem cell function. While MTG16 loss renders mice sensitive to chemical colitis, the role of MTG16 in the small intestine is unknown. Histological examination revealed that Mtg16(-/-) mice have increased enterocyte proliferation and goblet cell deficiency. After exposure to radiation, Mtg16(-/-) mice exhibited increased crypt viability and decreased apoptosis compared with wild-type (WT) mice. Flow cytometric and immunofluorescence analysis of intestinal epithelial cells for phospho-histone H2A.X also indicated decreased DNA damage and apoptosis in Mtg16(-/-) intestines. To determine if Mtg16 deletion affected epithelial cells in a cell-autonomous fashion, intestinal crypts were isolated from Mtg16(-/-) mice. Mtg16(-/-) and WT intestinal crypts showed similar enterosphere forming efficiencies when cultured in the presence of EGF, Noggin, and R-spondin. However, when Mtg16(-/-) crypts were cultured in the presence of Wnt3a, they demonstrated higher enterosphere forming efficiencies and delayed progression to mature enteroids. Mtg16(-/-) intestinal crypts isolated from irradiated mice exhibited increased survival compared with WT intestinal crypts. Interestingly, Mtg16 expression was reduced in a stem cell-enriched population at the time of crypt regeneration. This is consistent with MTG16 negatively regulating regeneration in vivo. Taken together, our data demonstrate that MTG16 loss promotes radioresistance and impacts intestinal stem cell function, possibly due to shifting cellular response away from DNA damage-induced apoptosis and towards DNA repair after injury.
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Affiliation(s)
- Shenika V. Poindexter
- 1Department of Cancer Biology, Vanderbilt University School of Medicine, Nashville, Tennessee; ,7Vanderbilt Ingram Cancer Center, Vanderbilt University Medical Center, Nashville, Tennessee; and
| | - Vishruth K. Reddy
- 1Department of Cancer Biology, Vanderbilt University School of Medicine, Nashville, Tennessee; ,7Vanderbilt Ingram Cancer Center, Vanderbilt University Medical Center, Nashville, Tennessee; and ,8Medical Scientist Training Program, Vanderbilt University School of Medicine, Nashville, Tennessee
| | - Mukul K. Mittal
- 2Department of Medicine, Division of Gastroenterology, Vanderbilt University School of Medicine, Nashville, Tennessee; ,3Veterans Affairs Tennessee Valley Health Care System, Nashville, Tennessee;
| | - Amanda M. Williams
- 1Department of Cancer Biology, Vanderbilt University School of Medicine, Nashville, Tennessee; ,7Vanderbilt Ingram Cancer Center, Vanderbilt University Medical Center, Nashville, Tennessee; and
| | - M. Kay Washington
- 5Department of Pathology, Vanderbilt University School of Medicine, Nashville, Tennessee; ,7Vanderbilt Ingram Cancer Center, Vanderbilt University Medical Center, Nashville, Tennessee; and
| | - Elizabeth Harris
- 5Department of Pathology, Vanderbilt University School of Medicine, Nashville, Tennessee; ,7Vanderbilt Ingram Cancer Center, Vanderbilt University Medical Center, Nashville, Tennessee; and
| | - Amanda Mah
- 6Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill, North Carolina;
| | - Scott W. Hiebert
- 4Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee; ,7Vanderbilt Ingram Cancer Center, Vanderbilt University Medical Center, Nashville, Tennessee; and
| | - Kshipra Singh
- 2Department of Medicine, Division of Gastroenterology, Vanderbilt University School of Medicine, Nashville, Tennessee; ,3Veterans Affairs Tennessee Valley Health Care System, Nashville, Tennessee;
| | - Rupesh Chaturvedi
- 1Department of Cancer Biology, Vanderbilt University School of Medicine, Nashville, Tennessee; ,2Department of Medicine, Division of Gastroenterology, Vanderbilt University School of Medicine, Nashville, Tennessee; ,3Veterans Affairs Tennessee Valley Health Care System, Nashville, Tennessee; ,7Vanderbilt Ingram Cancer Center, Vanderbilt University Medical Center, Nashville, Tennessee; and
| | - Keith T. Wilson
- 1Department of Cancer Biology, Vanderbilt University School of Medicine, Nashville, Tennessee; ,2Department of Medicine, Division of Gastroenterology, Vanderbilt University School of Medicine, Nashville, Tennessee; ,3Veterans Affairs Tennessee Valley Health Care System, Nashville, Tennessee; ,7Vanderbilt Ingram Cancer Center, Vanderbilt University Medical Center, Nashville, Tennessee; and
| | - P. Kay Lund
- 6Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill, North Carolina;
| | - Christopher S. Williams
- 1Department of Cancer Biology, Vanderbilt University School of Medicine, Nashville, Tennessee; ,2Department of Medicine, Division of Gastroenterology, Vanderbilt University School of Medicine, Nashville, Tennessee; ,3Veterans Affairs Tennessee Valley Health Care System, Nashville, Tennessee; ,7Vanderbilt Ingram Cancer Center, Vanderbilt University Medical Center, Nashville, Tennessee; and
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17
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Nguyen H, Mariotti J, Bareyan D, Carnahan R, Cooper T, Williams C, Engel M. ANTI-MTG16 ANTIBODIES REVEAL MTG16 SUBCELLULAR DISTRIBUTION AND NUCLEOCYTOPLASMIC TRANSPORT IN ERYTHROLEUKEMIA CELLS. ANTIBODY TECHNOLOGY JOURNAL 2015; 5:27-41. [PMID: 36267145 PMCID: PMC9580851 DOI: 10.2147/anti.s74419] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
The myeloid translocation gene (MTG) family of transcriptional co-repressors consists of three highly conserved members; MTG8, MTG16 and MTGR1, each evolutionarily related to the Drosophila protein NERVY and with orthologs across the mammalian hierarchy. By coordinating coincident interactions between DNA binding proteins, other co-repressors and epigenetic effectors, MTG proteins occupy a critical nexus in transcriptional control complexes to profoundly impact the specification of cell fate. MTG family members are most conserved within Nervy Homology Regions (NHR) 1-4, with each region fulfilling functions common to the family. Studies of functional differences between MTG proteins require carefully qualified immunologic reagents specific to each family member. We have developed a group of α-MTG16 antibodies and carefully characterized their specificity for MTG16. These tools reveal that MTG16 is concentrated in the cytoplasm of erythroleukemia cell lines from human and mouse. Using the CRM1 antagonist, leptomycin-B, we show that MTG16 levels rise in the nucleus of MEL cells and decline in the cytoplasm. Together, these data indicate bidirectional movement of MTG16 between cytoplasmic and nuclear compartments. Our work reveals an unrecognized feature of MTG16 regulation that may impact cell fate specification and provides reagents to address important questions regarding MTG16 functions in vivo.
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Affiliation(s)
- Hong Nguyen
- Department of Pediatrics, Vanderbilt University School of Medicine
| | - Jolene Mariotti
- Department of Pediatrics, Vanderbilt University School of Medicine
| | - Diana Bareyan
- Department of Oncological Sciences, Huntsman Cancer Institute, University of Utah School of Medicine
| | - Robert Carnahan
- Department of Cancer Biology, Vanderbilt University School of Medicine
| | - Tracy Cooper
- Department of Cancer Biology, Vanderbilt University School of Medicine
| | | | - Michael Engel
- Department of Oncological Sciences, Huntsman Cancer Institute, University of Utah School of Medicine
- Department of Pediatrics, University of Utah School of Medicine and Primary Children’s Hospital
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18
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Parang B, Rosenblatt D, Williams AD, Washington MK, Revetta F, Short SP, Reddy VK, Hunt A, Shroyer NF, Engel ME, Hiebert SW, Williams CS. The transcriptional corepressor MTGR1 regulates intestinal secretory lineage allocation. FASEB J 2014; 29:786-95. [PMID: 25398765 DOI: 10.1096/fj.14-254284] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Notch signaling largely determines intestinal epithelial cell fate. High Notch activity drives progenitors toward absorptive enterocytes by repressing secretory differentiation programs, whereas low Notch permits secretory cell assignment. Myeloid translocation gene-related 1 (MTGR1) is a transcriptional corepressor in the myeloid translocation gene/Eight-Twenty-One family. Given that Mtgr1(-/-) mice have a dramatic reduction of intestinal epithelial secretory cells, we hypothesized that MTGR1 is a key repressor of Notch signaling. In support of this, transcriptome analysis of laser capture microdissected Mtgr1(-/-) intestinal crypts revealed Notch activation, and secretory markers Mucin2, Chromogranin A, and Growth factor-independent 1 (Gfi1) were down-regulated in Mtgr1(-/-) whole intestines and Mtgr1(-/-) enteroids. We demonstrate that MTGR1 is in a complex with Suppressor of Hairless Homolog, a key Notch effector, and represses Notch-induced Hairy/Enhancer of Split 1 activity. Moreover, pharmacologic Notch inhibition using a γ-secretase inhibitor (GSI) rescued the hyperproliferative baseline phenotype in the Mtgr1(-/-) intestine and increased production of goblet and enteroendocrine lineages in Mtgr1(-/-) mice. GSI increased Paneth cell production in wild-type mice but failed to do so in Mtgr1(-/-) mice. We determined that MTGR1 can interact with GFI1, a transcriptional corepressor required for Paneth cell differentiation, and repress GFI1 targets. Overall, the data suggest that MTGR1, a transcriptional corepressor well characterized in hematopoiesis, plays a critical role in intestinal lineage allocation.
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Affiliation(s)
- Bobak Parang
- *Department of Medicine, Division of Gastroenterology, Departments of Cancer Biology, Pathology, Microbiology, and Immunology, and Biochemistry, Vanderbilt University, Nashville, Tennessee, USA; Department of Biology, Lipscomb University, Nashville, Tennessee, USA; Division of Pediatrics-Gastroenterology, Baylor University School of Medicine, Houston, Texas, USA; Division of Pediatric Hematology/Oncology, University of Utah, Salt Lake City, Utah; and **Vanderbilt Ingram Cancer Center, Veterans Affairs, Tennessee Valley Health Care System, Nashville, Tennessee, USA
| | - Daniel Rosenblatt
- *Department of Medicine, Division of Gastroenterology, Departments of Cancer Biology, Pathology, Microbiology, and Immunology, and Biochemistry, Vanderbilt University, Nashville, Tennessee, USA; Department of Biology, Lipscomb University, Nashville, Tennessee, USA; Division of Pediatrics-Gastroenterology, Baylor University School of Medicine, Houston, Texas, USA; Division of Pediatric Hematology/Oncology, University of Utah, Salt Lake City, Utah; and **Vanderbilt Ingram Cancer Center, Veterans Affairs, Tennessee Valley Health Care System, Nashville, Tennessee, USA
| | - Amanda D Williams
- *Department of Medicine, Division of Gastroenterology, Departments of Cancer Biology, Pathology, Microbiology, and Immunology, and Biochemistry, Vanderbilt University, Nashville, Tennessee, USA; Department of Biology, Lipscomb University, Nashville, Tennessee, USA; Division of Pediatrics-Gastroenterology, Baylor University School of Medicine, Houston, Texas, USA; Division of Pediatric Hematology/Oncology, University of Utah, Salt Lake City, Utah; and **Vanderbilt Ingram Cancer Center, Veterans Affairs, Tennessee Valley Health Care System, Nashville, Tennessee, USA
| | - Mary K Washington
- *Department of Medicine, Division of Gastroenterology, Departments of Cancer Biology, Pathology, Microbiology, and Immunology, and Biochemistry, Vanderbilt University, Nashville, Tennessee, USA; Department of Biology, Lipscomb University, Nashville, Tennessee, USA; Division of Pediatrics-Gastroenterology, Baylor University School of Medicine, Houston, Texas, USA; Division of Pediatric Hematology/Oncology, University of Utah, Salt Lake City, Utah; and **Vanderbilt Ingram Cancer Center, Veterans Affairs, Tennessee Valley Health Care System, Nashville, Tennessee, USA
| | - Frank Revetta
- *Department of Medicine, Division of Gastroenterology, Departments of Cancer Biology, Pathology, Microbiology, and Immunology, and Biochemistry, Vanderbilt University, Nashville, Tennessee, USA; Department of Biology, Lipscomb University, Nashville, Tennessee, USA; Division of Pediatrics-Gastroenterology, Baylor University School of Medicine, Houston, Texas, USA; Division of Pediatric Hematology/Oncology, University of Utah, Salt Lake City, Utah; and **Vanderbilt Ingram Cancer Center, Veterans Affairs, Tennessee Valley Health Care System, Nashville, Tennessee, USA
| | - Sarah P Short
- *Department of Medicine, Division of Gastroenterology, Departments of Cancer Biology, Pathology, Microbiology, and Immunology, and Biochemistry, Vanderbilt University, Nashville, Tennessee, USA; Department of Biology, Lipscomb University, Nashville, Tennessee, USA; Division of Pediatrics-Gastroenterology, Baylor University School of Medicine, Houston, Texas, USA; Division of Pediatric Hematology/Oncology, University of Utah, Salt Lake City, Utah; and **Vanderbilt Ingram Cancer Center, Veterans Affairs, Tennessee Valley Health Care System, Nashville, Tennessee, USA
| | - Vishruth K Reddy
- *Department of Medicine, Division of Gastroenterology, Departments of Cancer Biology, Pathology, Microbiology, and Immunology, and Biochemistry, Vanderbilt University, Nashville, Tennessee, USA; Department of Biology, Lipscomb University, Nashville, Tennessee, USA; Division of Pediatrics-Gastroenterology, Baylor University School of Medicine, Houston, Texas, USA; Division of Pediatric Hematology/Oncology, University of Utah, Salt Lake City, Utah; and **Vanderbilt Ingram Cancer Center, Veterans Affairs, Tennessee Valley Health Care System, Nashville, Tennessee, USA
| | - Aubrey Hunt
- *Department of Medicine, Division of Gastroenterology, Departments of Cancer Biology, Pathology, Microbiology, and Immunology, and Biochemistry, Vanderbilt University, Nashville, Tennessee, USA; Department of Biology, Lipscomb University, Nashville, Tennessee, USA; Division of Pediatrics-Gastroenterology, Baylor University School of Medicine, Houston, Texas, USA; Division of Pediatric Hematology/Oncology, University of Utah, Salt Lake City, Utah; and **Vanderbilt Ingram Cancer Center, Veterans Affairs, Tennessee Valley Health Care System, Nashville, Tennessee, USA
| | - Noah F Shroyer
- *Department of Medicine, Division of Gastroenterology, Departments of Cancer Biology, Pathology, Microbiology, and Immunology, and Biochemistry, Vanderbilt University, Nashville, Tennessee, USA; Department of Biology, Lipscomb University, Nashville, Tennessee, USA; Division of Pediatrics-Gastroenterology, Baylor University School of Medicine, Houston, Texas, USA; Division of Pediatric Hematology/Oncology, University of Utah, Salt Lake City, Utah; and **Vanderbilt Ingram Cancer Center, Veterans Affairs, Tennessee Valley Health Care System, Nashville, Tennessee, USA
| | - Michael E Engel
- *Department of Medicine, Division of Gastroenterology, Departments of Cancer Biology, Pathology, Microbiology, and Immunology, and Biochemistry, Vanderbilt University, Nashville, Tennessee, USA; Department of Biology, Lipscomb University, Nashville, Tennessee, USA; Division of Pediatrics-Gastroenterology, Baylor University School of Medicine, Houston, Texas, USA; Division of Pediatric Hematology/Oncology, University of Utah, Salt Lake City, Utah; and **Vanderbilt Ingram Cancer Center, Veterans Affairs, Tennessee Valley Health Care System, Nashville, Tennessee, USA
| | - Scott W Hiebert
- *Department of Medicine, Division of Gastroenterology, Departments of Cancer Biology, Pathology, Microbiology, and Immunology, and Biochemistry, Vanderbilt University, Nashville, Tennessee, USA; Department of Biology, Lipscomb University, Nashville, Tennessee, USA; Division of Pediatrics-Gastroenterology, Baylor University School of Medicine, Houston, Texas, USA; Division of Pediatric Hematology/Oncology, University of Utah, Salt Lake City, Utah; and **Vanderbilt Ingram Cancer Center, Veterans Affairs, Tennessee Valley Health Care System, Nashville, Tennessee, USA
| | - Christopher S Williams
- *Department of Medicine, Division of Gastroenterology, Departments of Cancer Biology, Pathology, Microbiology, and Immunology, and Biochemistry, Vanderbilt University, Nashville, Tennessee, USA; Department of Biology, Lipscomb University, Nashville, Tennessee, USA; Division of Pediatrics-Gastroenterology, Baylor University School of Medicine, Houston, Texas, USA; Division of Pediatric Hematology/Oncology, University of Utah, Salt Lake City, Utah; and **Vanderbilt Ingram Cancer Center, Veterans Affairs, Tennessee Valley Health Care System, Nashville, Tennessee, USA
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Olivier-Van Stichelen S, Abramowitz LK, Hanover JA. X marks the spot: does it matter that O-GlcNAc transferase is an X-linked gene? Biochem Biophys Res Commun 2014; 453:201-7. [PMID: 24960196 DOI: 10.1016/j.bbrc.2014.06.068] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2014] [Accepted: 06/13/2014] [Indexed: 01/07/2023]
Abstract
O-GlcNAcylation has emerged as a critical post-translational modification important for a wide array of cellular processes. This modification has been identified on a large pool of intracellular proteins that have wide-ranging roles, including transcriptional regulation, cell cycle progression, and signaling, among others. Interestingly, in mammals the single gene encoding O-GlcNAc Transferase (OGT) is located on the X-chromosome near the Xist locus suggesting that tight dosage regulation is necessary for normal development. Herein, we highlight the importance of OGT dosage and consider how its genomic location can contribute to a gender-specific increased risk for a number of diseases.
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Affiliation(s)
- Stéphanie Olivier-Van Stichelen
- Laboratory of Cellular and Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institute of Health, Bethesda, MD 20892, USA
| | - Lara K Abramowitz
- Laboratory of Cellular and Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institute of Health, Bethesda, MD 20892, USA
| | - John A Hanover
- Laboratory of Cellular and Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institute of Health, Bethesda, MD 20892, USA.
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Expression profiling of ETO2-regulated miRNAs in erythroid cells: Possible influence on miRNA abundance. FEBS Open Bio 2013; 3:428-32. [PMID: 24251106 PMCID: PMC3821025 DOI: 10.1016/j.fob.2013.10.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2013] [Revised: 10/05/2013] [Accepted: 10/07/2013] [Indexed: 12/26/2022] Open
Abstract
ETO2 is a component of a protein complex containing master regulators of hematopoiesis, including GATA-1 and SCL/TAL1, and also has RNA binding properties. Although ETO2 has been reported to repress GATA-1 target genes through histone deacetylation of the target gene loci in erythroid cells, little is known about the contribution of ETO2 to microRNA (miRNA) regulation. Here, we conducted miRNA profiling in ETO2-overexpressing and ETO2-silenced K562 cells. The analysis suggests that ETO2 positively regulates the abundance of mature miRNAs, including miR-21, miR-29b and let-7e. Our data suggest a novel mode of ETO2-mediated target gene repression via effects on miRNA expression. miRNA profiling was conducted in ETO2-overexpressing and ETO2-silenced K562 cells. ETO2 positively regulates the abundance of miRNA. ETO2 positively regulates the expression of miR-21, miR-29b and let-7e.
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Key Words
- CBF1, core-binding factor 1
- ETO2
- ETO2 (CBFA2T3), core-binding factor, runt domain, alpha subunit 2, translocated to, 3
- Erythropoiesis
- IL-3, interleukin 3
- IMDM, Iscove’s Modified Dulbecco’s Media
- LMO2, LIM domain only 2
- RPMI, Roswell Park Memorial Institute
- SCF, stem cell factor
- cDNA, complementary DNA
- miRNA
- siRNA, small interfering RNA
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21
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Williams CS, Bradley AM, Chaturvedi R, Singh K, Piazuelo MB, Chen X, McDonough EM, Schwartz DA, Brown CT, Allaman MM, Coburn LA, Horst SN, Beaulieu DB, Choksi YA, Washington MK, Williams AD, Fisher MA, Zinkel SS, Peek RM, Wilson KT, Hiebert SW. MTG16 contributes to colonic epithelial integrity in experimental colitis. Gut 2013; 62:1446-55. [PMID: 22833394 PMCID: PMC3663894 DOI: 10.1136/gutjnl-2011-301439] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
OBJECTIVE The myeloid translocation genes (MTGs) are transcriptional corepressors with both Mtg8(-/-) and Mtgr1(-/-) mice showing developmental and/or differentiation defects in the intestine. We sought to determine the role of MTG16 in intestinal integrity. METHODS Baseline and stress induced colonic phenotypes were examined in Mtg16(-/-) mice. To unmask phenotypes, we treated Mtg16(-/-) mice with dextran sodium sulphate (DSS) or infected them with Citrobacter rodentium and the colons were examined for ulceration and for changes in proliferation, apoptosis and inflammation. RESULTS Mtg16(-/-) mice have altered immune subsets, suggesting priming towards Th1 responses. Mtg16(-/-) mice developed increased weight loss, diarrhoea, mortality and histological colitis and there were increased innate (Gr1(+), F4/80(+), CD11c(+) and MHCII(+); CD11c(+)) and Th1 adaptive (CD4) immune cells in Mtg16(-/-) colons after DSS treatment. Additionally, there was increased apoptosis and a compensatory increased proliferation in Mtg16(-/-) colons. Compared with wild-type mice, Mtg16(-/-) mice exhibited increased colonic CD4;IFN-γ cells in vehicle-treated and DSS-treated mice. Adoptive transfer of wild-type marrow into Mtg16(-/-) recipients did not rescue the Mtg16(-/-) injury phenotype. Isolated colonic epithelial cells from DSS-treated Mtg16(-/-) mice exhibited increased KC (Cxcl1) mRNA expression when compared with wild-type mice. Mtg16(-/-) mice infected with C rodentium had more severe colitis and greater bacterial colonisation. Last, MTG16 mRNA levels were reduced in human ulcerative colitis versus normal colon tissues. CONCLUSIONS These observations indicate that MTG16 is critical for colonocyte survival and regeneration in response to intestinal injury and provide evidence that this transcriptional corepressor regulates inflammatory recruitment in response to injury.
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Affiliation(s)
- Christopher S Williams
- Department of Medicine, Division of Gastroenterology, Vanderbilt University, Nashville, Tennessee, USA,Department of Cancer Biology, Vanderbilt University, Nashville, Tennessee, USA,Vanderbilt Ingram Cancer Center, Nashville, Tennessee, USA,Veterans Affairs Tennessee Valley Healthcare System, Nashville, Tennessee, USA
| | - Amber M Bradley
- Department of Medicine, Division of Gastroenterology, Vanderbilt University, Nashville, Tennessee, USA
| | - Rupesh Chaturvedi
- Department of Medicine, Division of Gastroenterology, Vanderbilt University, Nashville, Tennessee, USA,Veterans Affairs Tennessee Valley Healthcare System, Nashville, Tennessee, USA
| | - Kshipra Singh
- Department of Medicine, Division of Gastroenterology, Vanderbilt University, Nashville, Tennessee, USA,Veterans Affairs Tennessee Valley Healthcare System, Nashville, Tennessee, USA
| | - Maria B Piazuelo
- Department of Medicine, Division of Gastroenterology, Vanderbilt University, Nashville, Tennessee, USA
| | - Xi Chen
- Department of Biostatistics, Vanderbilt University, Nashville, Tennessee, USA
| | - Elizabeth M McDonough
- Department of Pediatrics, Division of Pediatric Gastroenterology, Vanderbilt University, Nashville, Tennessee, USA
| | - David A Schwartz
- Department of Medicine, Division of Gastroenterology, Vanderbilt University, Nashville, Tennessee, USA
| | - Caroline T Brown
- Department of Medicine, Division of Gastroenterology, Vanderbilt University, Nashville, Tennessee, USA
| | - Margaret M Allaman
- Department of Medicine, Division of Gastroenterology, Vanderbilt University, Nashville, Tennessee, USA
| | - Lori A Coburn
- Department of Medicine, Division of Gastroenterology, Vanderbilt University, Nashville, Tennessee, USA,Veterans Affairs Tennessee Valley Healthcare System, Nashville, Tennessee, USA
| | - Sara N Horst
- Department of Medicine, Division of Gastroenterology, Vanderbilt University, Nashville, Tennessee, USA,Veterans Affairs Tennessee Valley Healthcare System, Nashville, Tennessee, USA
| | - Dawn B Beaulieu
- Department of Medicine, Division of Gastroenterology, Vanderbilt University, Nashville, Tennessee, USA
| | - Yash A Choksi
- Department of Medicine, Division of Gastroenterology, Vanderbilt University, Nashville, Tennessee, USA
| | | | - Amanda D Williams
- Department of Medicine, Division of Gastroenterology, Vanderbilt University, Nashville, Tennessee, USA
| | - Melissa A Fisher
- Department of Biochemistry, Vanderbilt University, Nashville, Tennessee, USA
| | - Sandra S Zinkel
- Department of Cancer Biology, Vanderbilt University, Nashville, Tennessee, USA,Vanderbilt Ingram Cancer Center, Nashville, Tennessee, USA
| | - Richard M Peek
- Department of Medicine, Division of Gastroenterology, Vanderbilt University, Nashville, Tennessee, USA,Vanderbilt Ingram Cancer Center, Nashville, Tennessee, USA,Veterans Affairs Tennessee Valley Healthcare System, Nashville, Tennessee, USA
| | - Keith T Wilson
- Department of Medicine, Division of Gastroenterology, Vanderbilt University, Nashville, Tennessee, USA,Department of Cancer Biology, Vanderbilt University, Nashville, Tennessee, USA,Vanderbilt Ingram Cancer Center, Nashville, Tennessee, USA,Veterans Affairs Tennessee Valley Healthcare System, Nashville, Tennessee, USA
| | - Scott W Hiebert
- Vanderbilt Ingram Cancer Center, Nashville, Tennessee, USA,Department of Biochemistry, Vanderbilt University, Nashville, Tennessee, USA
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22
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Kaiso directs the transcriptional corepressor MTG16 to the Kaiso binding site in target promoters. PLoS One 2012; 7:e51205. [PMID: 23251453 PMCID: PMC3521008 DOI: 10.1371/journal.pone.0051205] [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] [Received: 07/31/2012] [Accepted: 10/30/2012] [Indexed: 11/20/2022] Open
Abstract
Myeloid translocation genes (MTGs) are transcriptional corepressors originally identified in acute myelogenous leukemia that have recently been linked to epithelial malignancy with non-synonymous mutations identified in both MTG8 and MTG16 in colon, breast, and lung carcinoma in addition to functioning as negative regulators of WNT and Notch signaling. A yeast two-hybrid approach was used to discover novel MTG binding partners. This screen identified the Zinc fingers, C2H2 and BTB domain containing (ZBTB) family members ZBTB4 and ZBTB38 as MTG16 interacting proteins. ZBTB4 is downregulated in breast cancer and modulates p53 responses. Because ZBTB33 (Kaiso), like MTG16, modulates Wnt signaling at the level of TCF4, and its deletion suppresses intestinal tumorigenesis in the ApcMin mouse, we determined that Kaiso also interacted with MTG16 to modulate transcription. The zinc finger domains of Kaiso as well as ZBTB4 and ZBTB38 bound MTG16 and the association with Kaiso was confirmed using co-immunoprecipitation. MTG family members were required to efficiently repress both a heterologous reporter construct containing Kaiso binding sites (4×KBS) and the known Kaiso target, Matrix metalloproteinase-7 (MMP-7/Matrilysin). Moreover, chromatin immunoprecipitation studies placed MTG16 in a complex occupying the Kaiso binding site on the MMP-7 promoter. The presence of MTG16 in this complex, and its contributions to transcriptional repression both required Kaiso binding to its binding site on DNA, establishing MTG16-Kaiso binding as functionally relevant in Kaiso-dependent transcriptional repression. Examination of a large multi-stage CRC expression array dataset revealed patterns of Kaiso, MTG16, and MMP-7 expression supporting the hypothesis that loss of either Kaiso or MTG16 can de-regulate a target promoter such as that of MMP-7. These findings provide new insights into the mechanisms of transcriptional control by ZBTB family members and broaden the scope of co-repressor functions for the MTG family, suggesting coordinate regulation of transcription by Kaiso/MTG complexes in cancer.
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23
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Role of transcriptional corepressor ETO2 in erythroid cells. Exp Hematol 2012; 41:303-15.e1. [PMID: 23127762 DOI: 10.1016/j.exphem.2012.10.015] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2012] [Revised: 10/02/2012] [Accepted: 10/30/2012] [Indexed: 02/08/2023]
Abstract
Transcriptional corepressor ETO2 is a component of a protein complex containing master regulators of hematopoiesis, including GATA-1, SCL/TAL1, LMO2, and LDB1. To elucidate the role of ETO2 during erythroid differentiation, including the effects of ETO2 on GATA-1 targets, we performed gene expression profiling using K562 cells overexpressed with ETO2. The analysis demonstrated that 667 and 598 genes were upregulated and downregulated (more than twofold), respectively, in ETO2-overexpressing cells. ETO2-repressed genes included those encoding prototypical erythroid proteins. To test what percentages of ETO2-repressed genes could be direct target genes of GATA-1 in K562 cells, we merged the microarray results with ChIP-seq profile (n = 5,749), demonstrating that 23.1% of ETO2-repressed genes contained significant GATA-1 in their loci. However, there was no significant enrichment of PU.1 target genes among ETO2-repressed genes. Gene ontology analysis among ETO2-repressed genes revealed significant enrichment of genes related to "oxygen transporter," corresponding to globin genes. Quantitative chromatin immunoprecipitation and ETO2 knockdown analyses confirmed that ETO2 directly regulates globin genes in K562 cells. Next, we evaluated the role of ETO2 in human primary erythroblasts, derived from cord blood CD34-positive cells. In an ex vivo model of erythroid differentiation from CD34-positive cells, ETO2 protein level peaked at day 2-4 and almost diminished at the later stage of differentiation. Furthermore, short hairpin RNA-mediated knockdown and retroviral vector-mediated overexpression of ETO2 in primary erythroblasts suggested that ETO2 significantly represses HBB, HBA, and ALAS2 expression. In summary, ETO2 regulates GATA-1 target genes critical for erythroid differentiation, and the decrease of ETO2 levels during erythroid differentiation would contribute to the activation of these targets.
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24
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Cadigan KM, Waterman ML. TCF/LEFs and Wnt signaling in the nucleus. Cold Spring Harb Perspect Biol 2012; 4:cshperspect.a007906. [PMID: 23024173 DOI: 10.1101/cshperspect.a007906] [Citation(s) in RCA: 517] [Impact Index Per Article: 43.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
T-cell factor/lymphoid enhancer factor (TCF/LEF) transcription factors are the major end point mediators of Wnt/Wingless signaling throughout metazoans. TCF/LEFs are multifunctional proteins that use their sequence-specific DNA-binding and context-dependent interactions to specify which genes will be regulated by Wnts. Much of the work to define their actions has focused on their ability to repress target gene expression when Wnt signals are absent and to recruit β-catenin to target genes for activation when Wnts are present. Recent advances have highlighted how these on/off actions are regulated by Wnt signals and stabilized β-catenin. In contrast to invertebrates, which typically contain one TCF/LEF protein that can both activate and repress Wnt targets, gene duplication and isoform complexity of the family in vertebrates have led to specialization, in which individual TCF/LEF isoforms have distinct activities.
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Affiliation(s)
- Ken M Cadigan
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, 48109-1048, USA
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25
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The many faces and functions of β-catenin. EMBO J 2012; 31:2714-36. [PMID: 22617422 DOI: 10.1038/emboj.2012.150] [Citation(s) in RCA: 1175] [Impact Index Per Article: 97.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2012] [Accepted: 04/30/2012] [Indexed: 02/07/2023] Open
Abstract
β-Catenin (Armadillo in Drosophila) is a multitasking and evolutionary conserved molecule that in metazoans exerts a crucial role in a multitude of developmental and homeostatic processes. More specifically, β-catenin is an integral structural component of cadherin-based adherens junctions, and the key nuclear effector of canonical Wnt signalling in the nucleus. Imbalance in the structural and signalling properties of β-catenin often results in disease and deregulated growth connected to cancer and metastasis. Intense research into the life of β-catenin has revealed a complex picture. Here, we try to capture the state of the art: we try to summarize and make some sense of the processes that regulate β-catenin, as well as the plethora of β-catenin binding partners. One focus will be the interaction of β-catenin with different transcription factors and the potential implications of these interactions for direct cross-talk between β-catenin and non-Wnt signalling pathways.
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26
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Myeloid translocation gene 16 is required for maintenance of haematopoietic stem cell quiescence. EMBO J 2012; 31:1494-505. [PMID: 22266796 DOI: 10.1038/emboj.2011.500] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2011] [Accepted: 12/16/2011] [Indexed: 01/21/2023] Open
Abstract
The t(8;21) and t(16;21) that are associated with acute myeloid leukaemia disrupt two closely related genes termed Myeloid Translocation Genes 8 (MTG8) and 16 (MTG16), respectively. Many of the transcription factors that recruit Mtg16 regulate haematopoietic stem and progenitor cell functions and are required to maintain stem cell self-renewal potential. Accordingly, we found that Mtg16-null bone marrow (BM) failed in BM transplant assays. Moreover, when removed from the animal, Mtg16-deficient stem cells continued to show defects in stem cell self-renewal assays, suggesting a requirement for Mtg16 in this process. Gene expression analysis indicated that Mtg16 was required to suppress the expression of several key cell-cycle regulators including E2F2, and chromatin immunoprecipitation assays detected Mtg16 near an E2A binding site within the first intron of E2F2. BrdU incorporation assays indicated that in the absence of Mtg16 more long-term stem cells were in the S phase, even after competitive BM transplantation where normal stem and progenitor cells are present, suggesting that Mtg16 plays a role in the maintenance of stem cell quiescence.
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27
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Abstract
Wnts are conserved, secreted signaling proteins that can influence cell behavior by stabilizing β-catenin. Accumulated β-catenin enters the nucleus, where it physically associates with T-cell factor (TCF) family members to regulate target gene expression in many developmental and adult tissues. Recruitment of β-catenin to Wnt response element (WRE) chromatin converts TCFs from transcriptional repressors to activators. This review will outline the complex interplay between factors contributing to TCF repression and coactivators working with β-catenin to regulate Wnt targets. In addition, three variations of the standard transcriptional switch model will be discussed. One is the Wnt/β-catenin symmetry pathway in Caenorhabditis elegans, where Wnt-mediated nuclear efflux of TCF is crucial for activation of targets. Another occurs in vertebrates, where distinct TCF family members are associated with repression and activation, and recent evidence suggests that Wnt signaling facilitates a "TCF exchange" on WRE chromatin. Finally, a "reverse switch" mechanism for target genes that are directly repressed by Wnt/β-catenin signaling occurs in Drosophila cells. The diversity of TCF regulatory mechanisms may help to explain how a small group of transcription factors can function in so many different contexts to regulate target gene expression.
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Affiliation(s)
- Ken M Cadigan
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, Michigan, USA
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28
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Abstract
Mtg16/Eto2 is a transcriptional corepressor that is disrupted by t(16;21) in acute myeloid leukemia. Using mice lacking Mtg16, we found that Mtg16 is a critical regulator of T-cell development. Deletion of Mtg16 led to reduced thymocyte development in vivo, and after competitive bone marrow transplantation, there was a nearly complete failure of Mtg16(-/-) cells to contribute to thymocyte development. This defect was recapitulated in vitro as Mtg16(-/-) Lineage(-)/Sca1(+)/c-Kit(+) (LSK) cells of the bone marrow or DN1 cells of the thymus failed to produce CD4(+)/CD8(+) cells in response to a Notch signal. Complementation of these defects by reexpressing Mtg16 showed that 3 highly conserved domains were somewhat dispensable for T-cell development but required the capacity of Mtg16 to suppress E2A-dependent transcriptional activation and to bind to the Notch intracellular domain. Thus, Mtg16 integrates the activities of signaling pathways and nuclear factors in the establishment of T-cell fate specification.
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29
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Barrett CW, Fingleton B, Williams A, Ning W, Fischer MA, Washington MK, Chaturvedi R, Wilson KT, Hiebert SW, Williams CS. MTGR1 is required for tumorigenesis in the murine AOM/DSS colitis-associated carcinoma model. Cancer Res 2011; 71:1302-12. [PMID: 21303973 DOI: 10.1158/0008-5472.can-10-3317] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Myeloid Translocation Gene, Related-1 (MTGR1) CBFA2T2 is a member of the Myeloid Translocation Gene (MTG) family of transcriptional corepressors. The remaining two family members, MTG8 (RUNX1T1) and MTG16 (CBFA2T3) are identified as targets of chromosomal translocations in acute myeloid leukemia (AML). Mtgr1(-/-) mice have defects in intestinal lineage allocation and wound healing. Moreover, these mice show signs of impaired intestinal stem cell function. Based on these phenotypes, we hypothesized that MTGR1 may influence tumorigenesis arising in an inflammatory background. We report that Mtgr1(-/-) mice were protected from tumorigenesis when injected with azoxymethane (AOM) and then subjected to repeated cycles of dextran sodium sulfate (DSS). Tumor cell proliferation was comparable, but Mtgr1(-/-) tumors had significantly higher apoptosis rates. These phenotypes were dependent on epithelial injury, the resultant inflammation, or a combination of both as there was no difference in aberrant crypt foci (ACF) or tumor burden when animals were treated with AOM as the sole agent. Gene expression analysis indicated that Mtgr1(-/-) tumors had significant upregulation of inflammatory networks, and immunohistochemistry (IHC) for immune cell subsets revealed a marked multilineage increase in infiltrates, consisting predominately of CD3(+) and natural killer T (NKT) cells as well as macrophages. Transplantation of wild type (WT) bone marrow into Mtgr1(-/-) mice, and the reciprocal transplant, did not alter the phenotype, ruling out an MTGR1 hematopoietic cell-autonomous mechanism. Our findings indicate that MTGR1 is required for efficient inflammatory carcinogenesis in this model, and implicate its dysfunction in colitis-associated carcinoma. This represents the first report functionally linking MTGR1 to intestinal tumorigenesis.
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Affiliation(s)
- Caitlyn W Barrett
- Department of Medicine/Gastroenterology, Vanderbilt Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
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30
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Cadigan KM, Peifer M. Wnt signaling from development to disease: insights from model systems. Cold Spring Harb Perspect Biol 2010; 1:a002881. [PMID: 20066091 DOI: 10.1101/cshperspect.a002881] [Citation(s) in RCA: 222] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
One of the early surprises in the study of cell adhesion was the discovery that beta-catenin plays dual roles, serving as an essential component of cadherin-based cell-cell adherens junctions and also serving as the key regulated effector of the Wnt signaling pathway. Here, we review our current model of Wnt signaling and discuss how recent work using model organisms has advanced our understanding of the roles Wnt signaling plays in both normal development and in disease. These data help flesh out the mechanisms of signaling from the membrane to the nucleus, revealing new protein players and providing novel information about known components of the pathway.
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Affiliation(s)
- Ken M Cadigan
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan 48109-1048, USA
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31
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Genetic manipulation of AML1-ETO-induced expansion of hematopoietic precursors in a Drosophila model. Blood 2010; 116:4612-20. [PMID: 20688956 DOI: 10.1182/blood-2010-03-276998] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Among mutations in human Runx1/AML1 transcription factors, the t(8;21)(q22;q22) genomic translocation that creates an AML1-ETO fusion protein is implicated in etiology of the acute myeloid leukemia. To identify genes and components associated with this oncogene we used Drosophila as a genetic model. Expression of AML1-ETO caused an expansion of hematopoietic precursors in Drosophila, which expressed high levels of reactive oxygen species (ROS). Mutations in functional domains of the fusion protein suppress the proliferative phenotype. In a genetic screen, we found that inactivation of EcRB1 or activation of Foxo and superoxide dismutase-2 (SOD2) suppress the AML1-ETO-induced phenotype by reducing ROS expression in the precursor cells. Our studies indicate that ROS is a signaling factor promoting maintenance of normal as well as the aberrant myeloid precursors and suggests the importance of antioxidant enzymes and their regulators as targets for further study in the context of leukemia.
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32
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Aaker JD, Patineau AL, Yang HJ, Ewart DT, Nakagawa Y, McLoon SC, Koyano-Nakagawa N. Interaction of MTG family proteins with NEUROG2 and ASCL1 in the developing nervous system. Neurosci Lett 2010; 474:46-51. [PMID: 20214951 DOI: 10.1016/j.neulet.2010.03.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2009] [Revised: 02/18/2010] [Accepted: 03/02/2010] [Indexed: 12/21/2022]
Abstract
During neural development, members of MTG family of transcriptional repressors are induced by proneural basic helix-loop-helix (bHLH) transcription factors and in turn inhibit the activity of the bHLH proteins, forming a negative feedback loop that regulates the normal progression of neurogenesis. Three MTG genes, MTG8, MTG16 and MTGR1, are expressed in distinct patterns in the developing nervous system. Various bHLH proteins are also expressed in distinct patterns. We asked whether there is a functional relationship between specific MTG and bHLH proteins in developing chick spinal cord. First, we examined if each MTG gene is induced by specific bHLH proteins. Although expression of NEUROG2, ASCL1 and MTG genes overlapped, the boundaries of gene expression did not match. Ectopic expression analysis showed that MTGR1 and NEUROD4, which show similar expression patterns, are regulated differently by NEUROG2 and ASCL1. Thus, our results show that expression of MTG genes is not regulated by a single upstream bHLH protein, but represents an integration of the activity of multiple regulators. Next, we asked if each MTG protein inhibits specific bHLH proteins. Transcription assay showed that NEUROG2 and ASCL1 are inhibited by MTGR1 and MTG16, and less efficiently by MTG8. Deletion mapping of MTGR1 showed that MTGR1 binds NEUROG2 and ASCL1 using multiple interaction surfaces, and all conserved domains are required for its repressor activity. These results support the model that MTG proteins form a higher-order repressor complex and modulate transcriptional activity of bHLH proteins during neurogenesis.
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Affiliation(s)
- Joshua D Aaker
- Department of Neuroscience, United States; Stem Cell Institute, United States
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Myeloid translocation gene 16 (MTG16) interacts with Notch transcription complex components to integrate Notch signaling in hematopoietic cell fate specification. Mol Cell Biol 2010; 30:1852-63. [PMID: 20123979 DOI: 10.1128/mcb.01342-09] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The Notch signaling pathway regulates gene expression programs to influence the specification of cell fate in diverse tissues. In response to ligand binding, the intracellular domain of the Notch receptor is cleaved by the gamma-secretase complex and then translocates to the nucleus. There, it binds the transcriptional repressor CSL, triggering its conversion to an activator of Notch target gene expression. The events that control this conversion are poorly understood. We show that the transcriptional corepressor, MTG16, interacts with both CSL and the intracellular domains of Notch receptors, suggesting a pivotal role in regulation of the Notch transcription complex. The Notch1 intracellular domain disrupts the MTG16-CSL interaction. Ex vivo fate specification in response to Notch signal activation is impaired in Mtg16-/- hematopoietic progenitors, and restored by MTG16 expression. An MTG16 derivative lacking the binding site for the intracellular domain of Notch1 fails to restore Notch-dependent cell fate. These data suggest that MTG16 interfaces with critical components of the Notch transcription complex to affect Notch-dependent lineage allocation in hematopoiesis.
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Alishahi A, Koyano-Nakagawa N, Nakagawa Y. Regional expression of MTG genes in the developing mouse central nervous system. Dev Dyn 2009; 238:2095-102. [PMID: 19618476 DOI: 10.1002/dvdy.22021] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Myeloid translocation gene (MTG) proteins are transcriptional repressors that are highly conserved across species. We studied the expression of three members of this gene family, MTGR1, MTG8, and MTG16 in developing mouse central nervous system by in situ hybridization. All of these genes are detected as early as embryonic day 11.5. Because these genes are known to be induced by proneural genes during neurogenesis, we analyzed the expression of MTG genes in relation to two proneural genes, Neurog2 (also known as Ngn2 or Neurogenin 2) and Ascl1 (also known as Mash1). While MTGR1 are generally expressed in regions that also express Neurog2, MTG8 and MTG16 expression is associated more tightly with that of Ascl1-expressing neural progenitor cells. These results suggest the possibility that expression of MTG genes is differentially controlled by specific proneural genes during neurogenesis.
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Affiliation(s)
- Amin Alishahi
- Department of Neuroscience and Stem Cell Institute, University of Minnesota Medical School, Minneapolis, Minnesota 55455, USA
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Abstract
Paneth cells (PCs) are specialized epithelial cells predominantly found in the small intestinal crypts of Lieberkuehn. They produce different broad spectrum antimicrobial peptides most abundantly the alpha-defensins HD-5 and -6 (DEFA5 und DEFA6). Both these PC products show a specific reduction in small intestinal Crohn's disease (CD) - a form of inflammatory bowel disease (IBD). Their decrease is independent of current inflammation and an association with a NOD2 frameshift mutation has been demonstrated. More recently, another independent and even more frequent mechanism has been found which is linked to diminished levels of the Wnt pathway transcription factor TCF7L2 (also known as TCF4). Besides regulating the expression of HD-5 and HD-6 as TCF4 target genes, the Wnt pathway also orchestrates Paneth cell differentiation and maturation and controls stem cell maintenance in the small intestine. Besides NOD2 (which is predominantly expressed in PC) and ATG16L1 (inter alia important in the exocytosis of PC products), TCF4 is the third gene which is associated with small intestinal CD and Paneth cell antimicrobial function. Thus, Paneth cells seem to be key player emphazising a paramount importance of antimicrobial host defense in small intestinal CD pathogenesis.
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Engel ME, Hiebert SW. Proleukemic RUNX1 and CBFbeta mutations in the pathogenesis of acute leukemia. Cancer Treat Res 2009; 145:127-47. [PMID: 20306249 DOI: 10.1007/978-0-387-69259-3_8] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The existence of non-random mutations in critical regulators of cell growth and differentiation is a recurring theme in cancer pathogenesis and provides the basis for our modern, molecular approach to the study and treatment of malignant diseases. Nowhere is this more true than in the study of leukemogenesis, where research has converged upon a critical group of genes involved in hematopoietic stem and progenitor cell self-renewal and fate specification. Prominent among these is the heterodimeric transcriptional regulator, RUNX1/CBFbeta. RUNX1 is a site-specific DNA-binding protein whose consensus response element is found in the promoters of many hematopoietically relevant genes. CBFbeta interacts with RUNX1, stabilizing its interaction with DNA to promote the actions of RUNX1/CBFbeta in transcriptional control. Both the RUNX1 and the CBFbeta genes participate in proleukemic chromosomal alterations. Together they contribute to approximately one-third of acute myelogenous leukemia (AML) and one-quarter of acute lymphoblastic leukemia (ALL) cases, making RUNX1 and CBFbeta the most frequently affected genes known in the pathogenesis of acute leukemia. Investigating the mechanisms by which RUNX1, CBFbeta, and their proleukemic fusion proteins influence leukemogenesis has contributed greatly to our understanding of both normal and malignant hematopoiesis. Here we present an overview of the structural features of RUNX1/CBFbeta and their derivatives, their roles in transcriptional control, and their contributions to normal and malignant hematopoiesis.
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Affiliation(s)
- Michael E Engel
- Department of Pediatrics, Monroe Carell Jr. Children's Hospital, Nashville, TN, USA.
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Farmer TE, Williams CS, Washington MK, Hiebert SW. Inactivation of the p19(ARF) tumor suppressor affects intestinal epithelial cell proliferation and integrity. J Cell Biochem 2008; 104:2228-40. [PMID: 18442038 DOI: 10.1002/jcb.21779] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
p19(ARF) is a tumor suppressor that is frequently deleted in human cancer. It lies at chromosome 9p21 and shares exons 2 and 3 with p16(ink4a), which is also inactivated by these cancer-associated deletions. The "canonical pathway" by which p19(ARF) is thought to suppress tumorigenesis through activation of the p53 tumor suppressor. In response to hyperproliferative signals, such as expression of oncogenes, p19(ARF) is induced and binds to the MDM2 ubiquitin ligase, sequestering it in the nucleolus to allow the accumulation of p53. However, p19(ARF) also has MDM2 and p53 independent functions. In human colon cancer, p19(ARF) is only rarely deleted, but it is more frequently silenced by DNA promoter methylation. Here we show that inactivation of p19(ARF) in mice increases the number of cycling cells in the crypts of the colonic epithelium. Moreover, inactivation of p19(ARF) exacerbated the ulceration of the colonic epithelium caused by dextran sodium sulfate (DSS). These effects were similar to those observed in mice lacking myeloid translocation gene-related-1 (Mtgr1), and mice lacking both of these genes showed an even greater sensitivity to DSS. Surprisingly, inactivation of p19(ARF) restored the loss of the secretory lineage in mice deficient in Mtgr1, suggesting an additional role for p19(ARF) in the small intestinal epithelium.
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Affiliation(s)
- Tiffany E Farmer
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, USA
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