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Grabert K, Sehgal A, Irvine KM, Wollscheid-Lengeling E, Ozdemir DD, Stables J, Luke GA, Ryan MD, Adamson A, Humphreys NE, Sandrock CJ, Rojo R, Verkasalo VA, Mueller W, Hohenstein P, Pettit AR, Pridans C, Hume DA. A Transgenic Line That Reports CSF1R Protein Expression Provides a Definitive Marker for the Mouse Mononuclear Phagocyte System. THE JOURNAL OF IMMUNOLOGY 2020; 205:3154-3166. [DOI: 10.4049/jimmunol.2000835] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Accepted: 09/23/2020] [Indexed: 12/12/2022]
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Freem L, Summers KM, Gheyas AA, Psifidi A, Boulton K, MacCallum A, Harne R, O’Dell J, Bush SJ, Hume DA. Analysis of the Progeny of Sibling Matings Reveals Regulatory Variation Impacting the Transcriptome of Immune Cells in Commercial Chickens. Front Genet 2019; 10:1032. [PMID: 31803225 PMCID: PMC6870463 DOI: 10.3389/fgene.2019.01032] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Accepted: 09/25/2019] [Indexed: 01/05/2023] Open
Abstract
There is increasing recognition that the underlying genetic variation contributing to complex traits influences transcriptional regulation and can be detected at a population level as expression quantitative trait loci. At the level of an individual, allelic variation in transcriptional regulation of individual genes can be detected by measuring allele-specific expression in RNAseq data. We reasoned that extreme variants in gene expression could be identified by analysis of inbred progeny with shared grandparents. Commercial chickens have been intensively selected for production traits. Selection is associated with large blocks of linkage disequilibrium with considerable potential for co-selection of closely linked "hitch-hiker alleles" affecting traits unrelated to the feature being selected, such as immune function, with potential impact on the productivity and welfare of the animals. To test this hypothesis that there is extreme allelic variation in immune-associated genes we sequenced a founder population of commercial broiler and layer birds. These birds clearly segregated genetically based upon breed type. Each genome contained numerous candidate null mutations, protein-coding variants predicted to be deleterious and extensive non-coding polymorphism. We mated selected broiler-layer pairs then generated cohorts of F2 birds by sibling mating of the F1 generation. Despite the predicted prevalence of deleterious coding variation in the genomic sequence of the founders, clear detrimental impacts of inbreeding on survival and post-hatch development were detected in only one F2 sibship of 15. There was no effect on circulating leukocyte populations in hatchlings. In selected F2 sibships we performed RNAseq analysis of the spleen and isolated bone marrow-derived macrophages (with and without lipopolysaccharide stimulation). The results confirm the predicted emergence of very large differences in expression of individual genes and sets of genes. Network analysis of the results identified clusters of co-expressed genes that vary between individuals and suggested the existence of trans-acting variation in the expression in macrophages of the interferon response factor family that distinguishes the parental broiler and layer birds and influences the global response to lipopolysaccharide. This study shows that the impact of inbreeding on immune cell gene expression can be substantial at the transcriptional level, and potentially opens a route to accelerate selection using specific alleles known to be associated with desirable expression levels.
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Affiliation(s)
- Lucy Freem
- The Roslin Institute, University of Edinburgh, Edinburgh, United Kingdom
| | - Kim M. Summers
- Mater Research Institute-University of Queensland, Translational Research Institute, Woolloongabba, QLD, Australia
| | - Almas A. Gheyas
- The Roslin Institute, University of Edinburgh, Edinburgh, United Kingdom
| | - Androniki Psifidi
- Department of Clinical Sciences and Services, Royal Veterinary College, University of London, London, United Kingdom
| | - Kay Boulton
- The Roslin Institute, University of Edinburgh, Edinburgh, United Kingdom
| | - Amanda MacCallum
- The Roslin Institute, University of Edinburgh, Edinburgh, United Kingdom
| | - Rakhi Harne
- The Roslin Institute, University of Edinburgh, Edinburgh, United Kingdom
| | - Jenny O’Dell
- The Roslin Institute, University of Edinburgh, Edinburgh, United Kingdom
| | - Stephen J. Bush
- Nuffield Department of Clinical Medicine, University of Oxford, Oxford, United Kingdom
| | - David A. Hume
- Mater Research Institute-University of Queensland, Translational Research Institute, Woolloongabba, QLD, Australia
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3
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The evolution of the macrophage-specific enhancer (Fms intronic regulatory element) within the CSF1R locus of vertebrates. Sci Rep 2017; 7:17115. [PMID: 29215000 PMCID: PMC5719456 DOI: 10.1038/s41598-017-15999-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Accepted: 11/03/2017] [Indexed: 01/07/2023] Open
Abstract
The Csf1r locus encodes the receptor for macrophage colony-stimulating factor, which controls the proliferation, differentiation and survival of macrophages. The 300 bp Fms intronic regulatory element (FIRE), within the second intron of Csf1r, is necessary and sufficient to direct macrophage-specific transcription. We have analysed the conservation and divergence of the FIRE DNA sequence in vertebrates. FIRE is present in the same location in the Csf1r locus in reptile, avian and mammalian genomes. Nearest neighbor analysis based upon this element alone largely recapitulates phylogenies inferred from much larger genomic sequence datasets. One core element, containing binding sites for AP1 family and the macrophage-specific transcription factor, PU.1, is conserved from lizards to humans. Around this element, the FIRE sequence is conserved within clades with the most conserved elements containing motifs for known myeloid-expressed transcription factors. Conversely, there is little alignment between clades outside the AP1/PU.1 element. The analysis favours a hybrid between “enhanceosome” and “smorgasbord” models of enhancer function, in which elements cooperate to bind components of the available transcription factor milieu.
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C/EBPβ is required for survival of Ly6C - monocytes. Blood 2017; 130:1809-1818. [PMID: 28807982 DOI: 10.1182/blood-2017-03-772962] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Accepted: 08/07/2017] [Indexed: 02/06/2023] Open
Abstract
The transcription factor CCAAT/enhancer-binding protein β (C/EBPβ) is highly expressed in monocytes/macrophages. However, its roles in monopoiesis are largely unknown. Here, we investigated the roles of C/EBPβ in monopoiesis. Further subdivision of monocytes revealed that Cebpb messenger RNA was highly upregulated in Ly6C- monocytes in bone marrow. Accordingly, the number of Ly6C- monocytes was significantly reduced in Cebpb-/- mice. Bone marrow chimera experiments and Mx1-Cre-mediated deletion of Cebpb revealed a cell-intrinsic and monocyte-specific requirement for C/EBPβ in monopoiesis. In Cebpb-/- mice, turnover of Ly6C- monocytes was highly accelerated and apoptosis of Ly6C- monocytes was increased. Expression of Csf1r, which encodes a receptor for macrophage colony-stimulating factor, was significantly reduced in Ly6C- monocytes of Cebpb-/- mice. C/EBPβ bound to positive regulatory elements of Csf1r and promoted its transcription. Collectively, these results indicate that C/EBPβ is a critical factor for Ly6C- monocyte survival, at least in part through upregulation of Csf1r.
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5
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Transcriptional mechanisms that control expression of the macrophage colony-stimulating factor receptor locus. Clin Sci (Lond) 2017; 131:2161-2182. [DOI: 10.1042/cs20170238] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Revised: 05/22/2017] [Accepted: 06/11/2017] [Indexed: 12/17/2022]
Abstract
The proliferation, differentiation, and survival of cells of the macrophage lineage depends upon signals from the macrophage colony-stimulating factor (CSF) receptor (CSF1R). CSF1R is expressed by embryonic macrophages and induced early in adult hematopoiesis, upon commitment of multipotent progenitors to the myeloid lineage. Transcriptional activation of CSF1R requires interaction between members of the E26 transformation-specific family of transcription factors (Ets) (notably PU.1), C/EBP, RUNX, AP-1/ATF, interferon regulatory factor (IRF), STAT, KLF, REL, FUS/TLS (fused in sarcoma/ranslocated in liposarcoma) families, and conserved regulatory elements within the mouse and human CSF1R locus. One element, the Fms-intronic regulatory element (FIRE), within intron 2, is conserved functionally across all the amniotes. Lineage commitment in multipotent progenitors also requires down-regulation of specific transcription factors such as MYB, FLI1, basic leucine zipper transcriptional factor ATF-like (BATF3), GATA-1, and PAX5 that contribute to differentiation of alternative lineages and repress CSF1R transcription. Many of these transcription factors regulate each other, interact at the protein level, and are themselves downstream targets of CSF1R signaling. Control of CSF1R transcription involves feed–forward and feedback signaling in which CSF1R is both a target and a participant; and dysregulation of CSF1R expression and/or function is associated with numerous pathological conditions. In this review, we describe the regulatory network behind CSF1R expression during differentiation and development of cells of the mononuclear phagocyte system.
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Zasłona Z, Scruggs AM, Peters-Golden M, Huang SK. Protein kinase A inhibition of macrophage maturation is accompanied by an increase in DNA methylation of the colony-stimulating factor 1 receptor gene. Immunology 2016; 149:225-37. [PMID: 27353657 DOI: 10.1111/imm.12641] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Revised: 06/17/2016] [Accepted: 06/27/2016] [Indexed: 01/21/2023] Open
Abstract
Macrophage colony-stimulating factor 1 (CSF-1) plays a critical role in the differentiation of mononuclear phagocytes from bone marrow precursors, and maturing monocytes and macrophages exhibit increased expression of the CSF-1 receptor, CSF1R. The expression of CSF1R is tightly regulated by transcription factors and epigenetic mechanisms. We previously showed that prostaglandin E2 and subsequent activation of protein kinase A (PKA) inhibited CSF1R expression and macrophage maturation. Here, we examine the DNA methylation changes that occur at the Csf1r locus during macrophage maturation in the presence or absence of activated PKA. Murine bone marrow cells were matured to macrophages by incubating cells with CSF-1-containing conditioned medium for up to 6 days in the presence or absence of the PKA agonist 6-bnz-cAMP. DNA methylation of Csf1r promoter and enhancer regions was assayed by bisulphite pyrosequencing. DNA methylation of Csf1r decreased during normal macrophage maturation in concert with an increase in Csf1r mRNA expression. Treatment with the PKA agonist inhibited Csf1r mRNA and protein expression, and increased DNA methylation at the Csf1r promoter. This was associated with decreased binding of the transcription factor PU.1 to the Csf1r promoter. Treatment with the PKA agonist inhibited the responsiveness of macrophages to CSF-1. Levels of endogenous PKA activity decreased during normal macrophage maturation, suggesting that attenuation of this signalling pathway contributes to the increase in CSF1R expression during macrophage maturation. Together, these results demonstrate that macrophage maturation is accompanied by Csf1r hypomethylation, and illustrates for the first time the ability of PKA to increase Csf1r DNA methylation.
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Affiliation(s)
- Zbigniew Zasłona
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Anne M Scruggs
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Marc Peters-Golden
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Steven K Huang
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI, USA
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Pridans C, Davis GM, Sauter KA, Lisowski ZM, Corripio-Miyar Y, Raper A, Lefevre L, Young R, McCulloch ME, Lillico S, Milne E, Whitelaw B, Hume DA. A Csf1r-EGFP Transgene Provides a Novel Marker for Monocyte Subsets in Sheep. THE JOURNAL OF IMMUNOLOGY 2016; 197:2297-305. [PMID: 27521343 PMCID: PMC5009875 DOI: 10.4049/jimmunol.1502336] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Accepted: 07/15/2016] [Indexed: 12/12/2022]
Abstract
Expression of Csf1r in adults is restricted to cells of the macrophage lineage. Transgenic reporters based upon the Csf1r locus require inclusion of the highly conserved Fms-intronic regulatory element for expression. We have created Csf1r-EGFP transgenic sheep via lentiviral transgenesis of a construct containing elements of the mouse Fms-intronic regulatory element and Csf1r promoter. Committed bone marrow macrophage precursors and blood monocytes express EGFP in these animals. Sheep monocytes were divided into three populations, similar to classical, intermediate, and nonclassical monocytes in humans, based upon CD14 and CD16 expression. All expressed EGFP, with increased levels in the nonclassical subset. Because Csf1r expression coincides with the earliest commitment to the macrophage lineage, Csf1r-EGFP bone marrow provides a tool for studying the earliest events in myelopoiesis using the sheep as a model.
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Affiliation(s)
- Clare Pridans
- The Roslin Institute, University of Edinburgh, Midlothian EH25 9RG, United Kingdom; and
| | - Gemma M Davis
- The Roslin Institute, University of Edinburgh, Midlothian EH25 9RG, United Kingdom; and
| | - Kristin A Sauter
- The Roslin Institute, University of Edinburgh, Midlothian EH25 9RG, United Kingdom; and
| | - Zofia M Lisowski
- The Roslin Institute, University of Edinburgh, Midlothian EH25 9RG, United Kingdom; and
| | | | - Anna Raper
- The Roslin Institute, University of Edinburgh, Midlothian EH25 9RG, United Kingdom; and
| | - Lucas Lefevre
- The Roslin Institute, University of Edinburgh, Midlothian EH25 9RG, United Kingdom; and
| | - Rachel Young
- The Roslin Institute, University of Edinburgh, Midlothian EH25 9RG, United Kingdom; and
| | - Mary E McCulloch
- The Roslin Institute, University of Edinburgh, Midlothian EH25 9RG, United Kingdom; and
| | - Simon Lillico
- The Roslin Institute, University of Edinburgh, Midlothian EH25 9RG, United Kingdom; and
| | - Elspeth Milne
- Royal (Dick) School of Veterinary Studies, University of Edinburgh, Midlothian EH25 9RG, United Kingdom
| | - Bruce Whitelaw
- The Roslin Institute, University of Edinburgh, Midlothian EH25 9RG, United Kingdom; and
| | - David A Hume
- The Roslin Institute, University of Edinburgh, Midlothian EH25 9RG, United Kingdom; and
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Pridans C, Lillico S, Whitelaw B, Hume DA. Lentiviral vectors containing mouse Csf1r control elements direct macrophage-restricted expression in multiple species of birds and mammals. MOLECULAR THERAPY-METHODS & CLINICAL DEVELOPMENT 2014; 1:14010. [PMID: 26015955 PMCID: PMC4362345 DOI: 10.1038/mtm.2014.10] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Accepted: 02/21/2014] [Indexed: 01/09/2023]
Abstract
The development of macrophages requires signaling through the lineage-restricted receptor Csf1r. Macrophage-restricted expression of transgenic reporters based upon Csf1r requires the highly conserved Fms-intronic regulatory element (FIRE). We have created a lentiviral construct containing mouse FIRE and promoter. The lentivirus is capable of directing macrophage-restricted reporter gene expression in mouse, rat, human, pig, cow, sheep, and even chicken. Rat bone marrow cells transduced with the lentivirus were capable of differentiating into macrophages expressing the reporter gene in vitro. Macrophage-restricted expression may be desirable for immunization or immune response modulation, and for gene therapy for lysosomal storage diseases and some immunodeficiencies. The small size of the Csf1r transcription control elements will allow the insertion of large "cargo" for applications in gene therapy and vaccine delivery.
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Affiliation(s)
- Clare Pridans
- The Roslin Institute, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Scotland , UK
| | - Simon Lillico
- The Roslin Institute, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Scotland , UK
| | - Bruce Whitelaw
- The Roslin Institute, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Scotland , UK
| | - David A Hume
- The Roslin Institute, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Scotland , UK
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9
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Transcriptional switching in macrophages associated with the peritoneal foreign body response. Immunol Cell Biol 2014; 92:518-26. [PMID: 24638066 DOI: 10.1038/icb.2014.19] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Revised: 02/13/2014] [Accepted: 02/16/2014] [Indexed: 01/29/2023]
Abstract
We previously demonstrated that myeloid cells are the source of fibrotic tissue induced by foreign material implanted in the peritoneal cavity. This study utilised the MacGreen mouse, in which the Csf1r promoter directs myeloid-specific enhanced green fluorescent protein (EGFP) expression, to determine the temporal gene expression profile of myeloid subpopulations recruited to the peritoneal cavity to encapsulate implanted foreign material (cubes of boiled egg white). Cells with high EGFP expression (EGFP(hi)) were purified from exudate and encapsulating tissue at different times during the foreign body response, gene expression profiles determined using cDNA microarrays, and data clustered using the network analysis tool, Biolayout Express(3D). EGFP(hi) cells from all time points expressed high levels of Csf1r, Emr1 (encoding F4/80), Cd14 and Itgam (encoding Mac-1) providing internal validation of their myeloid nature. Exudate macrophages (days 4-7) expressed a large cluster of cell cycle genes; these were switched off in capsule cells. Early in capsule formation, Csf1r-EGFP(hi) cells expressed genes associated with tissue turnover, but later expressed both pro- and anti-inflammatory genes alongside a subset of mesenchyme-associated genes, a pattern of gene expression that adds weight to the concept of a continuum of macrophage phenotypes rather than distinct M1/M2 subsets. Moreover, rather than transdifferentiating to myofibroblasts, macrophages contributing to later stages of the peritoneal foreign body response warrant their own classification as 'fibroblastoid' macrophages.
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Chockalingam S, Ghosh SS. Amelioration of cancer stem cells in macrophage colony stimulating factor-expressing U87MG-human glioblastoma upon 5-fluorouracil therapy. PLoS One 2013; 8:e83877. [PMID: 24391839 PMCID: PMC3877109 DOI: 10.1371/journal.pone.0083877] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2013] [Accepted: 11/08/2013] [Indexed: 12/31/2022] Open
Abstract
Macrophage colony stimulating factor (MCSF) regulates growth, proliferation and differentiation of haematopoietic cell lineages. Many cancers are known to secrete high level of MCSF, which recruit macrophages into the tumour micro-environment, supporting tumour growth. Herein, we report the cloning of MCSF and subsequent generation of U87MG expressing MCSF stable cell line (U87-MCSF). Cytotoxicity of anti-cancer drug 5-fluorouracil (5-FU) was evaluated on both U87MG and U87-MCSF cells. Interestingly, the proliferation of U87-MCSF cells was less (p<0.001) than that of U87MG cells alone, after treatment with 5-FU. Significant decrease in expression levels of cyclin E and A2 quantified by real time PCR analysis corroborated the reduced proliferation of 5-FU treated U87-MCSF cells. However, JC-1 staining did not reveal any apoptosis upon 5-FU treatment. Notch-1 upregulation induced a possible epithelial-mesenchymal transition in U87-MCSF cells, which accounted for an increase in the proportion of CD24high/CD44less cancer stem cells in U87-MCSF cells after 5-FU treatment. The elevated resistance of U87-MCSF cells towards 5-FU was due to the increase in the expressions (10.2 and 6 fold) of ABCB1 and mdm2, respectively. Furthermore, increase in expressions of ABCG1, mdm2 and CD24 was also observed in U87MG cells after prolonged incubation with 5-FU. Our studies provided mechanistic insights into drug resistance of U87MG cells and also described the pivotal role played by MCSF in augmenting the resistance of U87MG cells to 5-FU.
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Affiliation(s)
- S. Chockalingam
- Department of Biotechnology, Indian Institute of Technology Guwahati, Guwahati, Assam, India
| | - Siddhartha Sankar Ghosh
- Department of Biotechnology, Indian Institute of Technology Guwahati, Guwahati, Assam, India
- Centre for Nanotechnology, Indian Institute of Technology Guwahati, Guwahati, Assam, India
- * E-mail:
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11
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Sauter KA, Bouhlel MA, O’Neal J, Sester DP, Tagoh H, Ingram RM, Pridans C, Bonifer C, Hume DA. The function of the conserved regulatory element within the second intron of the mammalian Csf1r locus. PLoS One 2013; 8:e54935. [PMID: 23383005 PMCID: PMC3561417 DOI: 10.1371/journal.pone.0054935] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2012] [Accepted: 12/18/2012] [Indexed: 01/09/2023] Open
Abstract
The gene encoding the receptor for macrophage colony-stimulating factor (CSF-1R) is expressed exclusively in cells of the myeloid lineages as well as trophoblasts. A conserved element in the second intron, Fms-Intronic Regulatory Element (FIRE), is essential for macrophage-specific transcription of the gene. However, the molecular details of how FIRE activity is regulated and how it impacts the Csf1r promoter have not been characterised. Here we show that agents that down-modulate Csf1r mRNA transcription regulated promoter activity altered the occupancy of key FIRE cis-acting elements including RUNX1, AP1, and Sp1 binding sites. We demonstrate that FIRE acts as an anti-sense promoter in macrophages and reversal of FIRE orientation within its native context greatly reduced enhancer activity in macrophages. Mutation of transcription initiation sites within FIRE also reduced transcription. These results demonstrate that FIRE is an orientation-specific transcribed enhancer element.
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Affiliation(s)
- Kristin A. Sauter
- Developmental Biology, The Roslin Institute, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Roslin, United Kingdom
| | - M. Amine Bouhlel
- Section of Experimental Haematology, Leeds Institute of Molecular Medicine, University of Leeds, St James’s University Hospital, Leeds, United Kingdom
| | - Julie O’Neal
- Developmental Biology, The Roslin Institute, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Roslin, United Kingdom
| | - David P. Sester
- Developmental Biology, The Roslin Institute, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Roslin, United Kingdom
| | - Hiromi Tagoh
- Section of Experimental Haematology, Leeds Institute of Molecular Medicine, University of Leeds, St James’s University Hospital, Leeds, United Kingdom
| | - Richard M. Ingram
- Section of Experimental Haematology, Leeds Institute of Molecular Medicine, University of Leeds, St James’s University Hospital, Leeds, United Kingdom
| | - Clare Pridans
- Developmental Biology, The Roslin Institute, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Roslin, United Kingdom
| | - Constanze Bonifer
- Section of Experimental Haematology, Leeds Institute of Molecular Medicine, University of Leeds, St James’s University Hospital, Leeds, United Kingdom
- School of Cancer Sciences, Institute of Biomedical Research, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - David A. Hume
- Developmental Biology, The Roslin Institute, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Roslin, United Kingdom
- * E-mail:
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12
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Sasmono RT, Williams E. Generation and characterization of MacGreen mice, the Cfs1r-EGFP transgenic mice. Methods Mol Biol 2012; 844:157-76. [PMID: 22262441 DOI: 10.1007/978-1-61779-527-5_11] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Macrophage colony-stimulating factor (CSF-1) regulates the differentiation, proliferation, and survival of cells of the mononuclear phagocyte system. The activity of CSF-1 is mediated by the CSF-1 receptor (CSFlR, CD115) that is encoded by c-fms (Csf1r) protooncogene. The c-fms gene is expressed in macrophage, trophoblast cell lineages, and to some extent granulocytes. A reporter gene construct containing 3.5-kb of 5' flanking sequence and the downstream intron 2 of the c-fms gene directed expression of enhanced green fluorescent protein (EGFP) to cells expressing the c-fms gene including the macrophages and trophoblasts. EGFP was detected in trophoblasts from the earliest stage of implantation. During embryonic development, EGFP expression highlighted the large numbers of c-fms positive macrophages in most organs. These embryonic macrophages contribute to organogenesis and tissue remodeling. In adult c-fms EGFP transgenic mice, which have been called the MacGreen mice, EGFP expressed in all tissue macrophage populations and permitted convenient detection of tissue macrophages as well as facilitates their isolation from various tissues.
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Affiliation(s)
- R Tedjo Sasmono
- Eijkman Institute for Molecular Biology, Jl. Diponegoro 69, Jakarta 10430, Indonesia
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13
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Saleem SJ, Conrad DH. Hematopoietic cytokine-induced transcriptional regulation and Notch signaling as modulators of MDSC expansion. Int Immunopharmacol 2011; 11:808-15. [PMID: 21426948 DOI: 10.1016/j.intimp.2011.03.010] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2011] [Revised: 03/07/2011] [Accepted: 03/08/2011] [Indexed: 12/14/2022]
Abstract
Hematopoietic stem cells (HSCs) differentiate into mature lineage restricted blood cells under the influence of a complex network of hematopoietic cytokines, cytokine-mediated transcriptional regulators, and manifold intercellular signaling pathways. The classical model of hematopoiesis proposes that progenitor cells undergo a dichotomous branching into myelo-erythroid and lymphoid lineages. Nonetheless, erythroid and lymphoid restricted progenitors retain their myeloid potential, supporting the existence of an alternative 'myeloid-based' mechanism of hematopoiesis. In this case, abnormal pathology is capable of dysregulating hematopoiesis in favor of myelopoiesis. The accumulation of immature CD11b+Gr-1+ myeloid-derived suppressor cells (MDSCs) has been shown to correlate with the presence of several hematopoietic cytokines, transcription factors and signaling pathways, lending support to this hypothesis. Although the negative role of MDSCs in cancer development is firmly established, it is now understood that MDSCs can exert a paradoxical, positive effect on transplantation, autoimmunity, and sepsis. Our conflicted understanding of MDSC function and the complexity of hematopoietic cytokine signaling underscores the need to elucidate molecular pathways of MDSC expansion for the development of novel MDSC-based therapeutics.
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Affiliation(s)
- Sheinei J Saleem
- Department of Microbiology and Immunology, Virginia Commonwealth University, School of Medicine, Richmond, VA 23298, USA
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14
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Our evolving knowledge of the transcriptional landscape. Mamm Genome 2008; 19:663-6. [DOI: 10.1007/s00335-008-9140-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2008] [Accepted: 08/08/2008] [Indexed: 11/25/2022]
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15
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Bulloch K, Miller MM, Gal-Toth J, Milner TA, Gottfried-Blackmore A, Waters EM, Kaunzner UW, Liu K, Lindquist R, Nussenzweig MC, Steinman RM, McEwen BS. CD11c/EYFP transgene illuminates a discrete network of dendritic cells within the embryonic, neonatal, adult, and injured mouse brain. J Comp Neurol 2008; 508:687-710. [PMID: 18386786 DOI: 10.1002/cne.21668] [Citation(s) in RCA: 166] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The CD11c enhanced yellow fluorescent protein (EYFP) transgenic mouse was constructed to identify dendritic cells in the periphery (Lindquist et al. [2004] Nat. Immunol. 5:1243-1250). In this study, we used this mouse to characterize dendritic cells within the CNS. Our anatomic results showed discrete populations of EYFP(+) brain dendritic cells (EYFP(+) bDC) that colocalized with a small fraction of microglia immunoreactive for Mac-1, Iba-1, CD45, and F4/80 but not for NeuN, Dcx, NG2 proteoglycan, or GFAP. EYFP(+) bDC, isolated by fluorescent activated cell sorting (FACS), expressed mRNA for the Itgax (CD11c) gene, whereas FACS anlaysis of EYFP(+) bDC cultures revealed the presence of CD11c protein. Light microscopy studies revealed that EYFP(+) bDC were present in the embryonic CNS when the blood-brain barrier is formed and postnatally when brain cells are amenable to culturing. In adult male mice, EYFP(+) bDC distribution was prominent within regions of the CNS that 1) are subject to structural plasticity and neurogenesis, 2) receive sensory and humoral input from the external environment, and 3) lack a blood-brain barrier. Ultrastructural analysis of EYFP(+) bDC in adult neurogenic niches showed their proximity to developing neurons and a morphology characteristic of immune/microglia cells. Kainic acid-induced seizures revealed that EYFP(+) bDC responded to damage of the hippocampus and displayed morphologies similar to those described for seizure-activated EGFP(+) microglia in the hippocampus of cfms (CSF-1R) EGFP mice. Collectively, these findings suggest a new member of the dendritic cell family residing among the heterogeneous microglia population.
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Affiliation(s)
- Karen Bulloch
- Laboratory of Cellular Physiology and Immunology, The Rockefeller University, New York, New York 10065, USA.
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16
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Kurilova LS, Krutetskaya ZI, Lebedev OE, Antonov VG. The effect of oxidized glutathione and its pharmacological analogue glutoxim on intracellular Ca2+ concentration in macrophages Ca2+. ACTA ACUST UNITED AC 2008. [DOI: 10.1134/s1990519x08030139] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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17
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Hume DA, Sasmono T, Himes SR, Sharma SM, Bronisz A, Constantin M, Ostrowski MC, Ross IL. The Ewing Sarcoma Protein (EWS) Binds Directly to the Proximal Elements of the Macrophage-Specific Promoter of the CSF-1 Receptor (csf1r) Gene. THE JOURNAL OF IMMUNOLOGY 2008; 180:6733-42. [DOI: 10.4049/jimmunol.180.10.6733] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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18
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Su D, Gudas LJ. Retinoic acid receptor gamma activates receptor tyrosine kinase Tie1 gene transcription through transcription factor GATA4 in F9 stem cells. Exp Hematol 2008; 36:624-41. [PMID: 18439490 DOI: 10.1016/j.exphem.2007.12.016] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2007] [Revised: 12/19/2007] [Accepted: 12/31/2007] [Indexed: 01/10/2023]
Abstract
OBJECTIVE The retinoic acid receptors (RARs) alpha, beta2, and gamma regulate specific subsets of target genes during all-trans retinoic acid (RA) induced differentiation of F9 teratocarcinoma stem cells. The Tie1 gene exhibited reduced expression in RA-treated F9 RARgamma-/- cells as compared to wild-type (WT) by microarray analysis. Our goal was to analyze the Tie1 gene, which encodes a surface receptor tyrosine kinase expressed in the hematovascular system. MATERIALS AND METHODS We assessed Tie1, Tie2, Flk1, Runx1, Peg/Mest2, and angiopoietin-1 and 2 mRNA levels and Tie1 promoter activity. RESULTS We showed that RARgamma, but not RARalpha or RARbeta2, is required for Tie1 promoter activation by RA. Treatment with a RARgamma selective agonist plus a retinoid X receptor agonist (LGD1069) increased Tie1 mRNA levels by 11- +/- 2.5-fold 48 hours after RA addition in F9 WT, but not in F9 RARgamma-/- cells, by quantitative reverse transcription polymerase chain reaction. Multiple putative GATA elements were identified in the Tie1 proximal promoter. RA increased GATA4 transcripts by 12- +/- 1-fold in F9 WT at 48 hours, but not in F9 RARgamma-/- cells. In addition, transfection of a GATA4 expression vector increased Tie1 promoter/luciferase activity in both RA-treated F9 WT and RARgamma-/- cells. Tie1 promoter deletion analyses indicated that a region of the promoter that possessed multiple GATA sites mediated the RA-associated Tie1 transcriptional increase. CONCLUSIONS Our results indicate that GATA4 plays a role in the RA/RARgamma-associated transcriptional activation of the Tie1 promoter. An understanding of RAR specificity in RA signaling should result in insights into hematopoietic stem cell signaling and potentially in improved therapies for several human diseases.
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MESH Headings
- Animals
- Bexarotene
- Embryonal Carcinoma Stem Cells/drug effects
- Embryonal Carcinoma Stem Cells/metabolism
- GATA4 Transcription Factor/drug effects
- GATA4 Transcription Factor/metabolism
- Gene Expression Profiling
- Mice
- Promoter Regions, Genetic/drug effects
- RNA, Messenger/drug effects
- RNA, Messenger/genetics
- Receptor, TIE-1/drug effects
- Receptor, TIE-1/genetics
- Receptor, TIE-1/metabolism
- Receptors, Retinoic Acid/agonists
- Receptors, Retinoic Acid/drug effects
- Receptors, Retinoic Acid/metabolism
- Reverse Transcriptase Polymerase Chain Reaction
- Tetrahydronaphthalenes/pharmacology
- Transcription, Genetic/drug effects
- Transcription, Genetic/genetics
- Tretinoin/pharmacology
- Tumor Cells, Cultured
- Retinoic Acid Receptor gamma
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Affiliation(s)
- Dan Su
- Department of Pharmacology, Weill Cornell Medical College, New York NY 10065, USA
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19
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Gordon IO, Freedman RS. Defective Antitumor Function of Monocyte-Derived Macrophages from Epithelial Ovarian Cancer Patients. Clin Cancer Res 2006; 12:1515-24. [PMID: 16533776 DOI: 10.1158/1078-0432.ccr-05-2254] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE Monocytes/macrophages (MO/MA) are an important but heterogeneous population of immune inflammatory cells that have diverse effector functions. We examined and compared these differences in peripheral blood and ascites of epithelial ovarian cancer patients with peripheral blood of normal donors. EXPERIMENTAL DESIGN Comparisons were made of cell surface subsets, cytokine production, and FcR-dependent cytotoxicity of CD14+ MO/MA and the CD14brightCD16-HLA-DR+ MO/MA subset in normal donor peripheral blood and peripheral blood and ascites from epithelial ovarian cancer patients. Studies were done on monocyte-derived macrophages cultured with macrophage colony-stimulating factor and activated with lipopolysaccharide or a combination of lipopolysaccharide plus recombinant IFN-gamma. RESULTS We determined that MO/MA or its subset from epithelial ovarian cancer patients had altered morphology and significantly less antibody-dependent cell-mediated cytotoxicity and phagocytic activity than did MO/MA from normal donors. Our findings also showed that monocyte-derived macrophages from both epithelial ovarian cancer patients and normal donors produce macrophage colony-stimulating factor-stimulated cytokines, including interleukin-8, tumor necrosis factor-alpha, and interleukin-6. CONCLUSIONS These findings highlight for the first time the defective antibody-dependent cell-mediated cytotoxicity and phagocyte functions of epithelial ovarian cancer-associated MO/MA, which could have implications for immunobiotherapeutic strategies.
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MESH Headings
- Adenocarcinoma, Clear Cell/metabolism
- Adenocarcinoma, Clear Cell/pathology
- Antibody-Dependent Cell Cytotoxicity
- Ascitic Fluid/cytology
- Carcinoma, Endometrioid/metabolism
- Carcinoma, Endometrioid/pathology
- Carcinoma, Papillary/metabolism
- Carcinoma, Papillary/pathology
- Female
- HLA-DR Antigens/metabolism
- Humans
- Interleukin-6/metabolism
- Interleukin-8/metabolism
- Lipopolysaccharide Receptors/metabolism
- Macrophages/physiology
- Neoplasms, Glandular and Epithelial/immunology
- Neoplasms, Glandular and Epithelial/metabolism
- Neoplasms, Glandular and Epithelial/pathology
- Ovarian Neoplasms/immunology
- Ovarian Neoplasms/metabolism
- Ovarian Neoplasms/pathology
- Peritoneal Neoplasms/metabolism
- Peritoneal Neoplasms/pathology
- Phagocytosis
- Receptors, IgG/metabolism
- Tumor Cells, Cultured
- Tumor Necrosis Factor-alpha/metabolism
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Affiliation(s)
- Ilyssa O Gordon
- The University of Texas Graduate School of Biomedical Sciences and Department of Gynecologic Oncology, The University of Texas M.D. Anderson Cancer Center, Houston, Texas 77230-1439, USA
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20
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Sester DP, Trieu A, Brion K, Schroder K, Ravasi T, Robinson JA, McDonald RC, Ripoll V, Wells CA, Suzuki H, Hayashizaki Y, Stacey KJ, Hume DA, Sweet MJ. LPS regulates a set of genes in primary murine macrophages by antagonising CSF-1 action. Immunobiology 2005; 210:97-107. [PMID: 16164016 DOI: 10.1016/j.imbio.2005.05.004] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We previously reported that bacterial products such as LPS and CpG DNA down-modulated cell surface levels of the Colony Stimulating Factor (CSF)-1 receptor (CSF-1R) on primary murine macrophages in an all-or-nothing manner. Here we show that the ability of bacterial products to down-modulate the CSF-1R rendered bone marrow-derived macrophages (BMM) unresponsive to CSF-1 as assessed by Akt and ERK1/2 phosphorylation. Using toll-like receptor (tlr)9 as a model CSF-1-repressed gene, we show that LPS induced tlr9 expression in BMM only when CSF-1 was present, suggesting that LPS relieves CSF-1-mediated inhibition to induce gene expression. Using cDNA microarrays, we identified a cluster of similarly CSF-1 repressed genes in BMM. By real time PCR we confirmed that the expression of a selection of these genes, including integral membrane protein 2B (itm2b), receptor activity-modifying protein 2 (ramp2) and macrophage-specific gene 1 (mpg-1), were repressed by CSF-1 and were induced by LPS only in the presence of CSF-1. This pattern of gene regulation was also apparent in thioglycollate-elicited peritoneal macrophages (TEPM). LPS also counteracted CSF-1 action to induce mRNA expression of a number of transcription factors including interferon consensus sequence binding protein 1 (Icsbp1), suggesting that this mechanism leads to transcriptional reprogramming in macrophages. Since the majority of in vitro studies on macrophage biology do not include CSF-1, these genes represent a set of previously uncharacterised LPS-inducible genes. This study identifies a new mechanism of macrophage activation, in which LPS (and other toll-like receptor agonists) regulate gene expression by switching off the CSF-1R signal. This finding also provides a biological relevance to the well-documented ability of macrophage activators to down-modulate surface expression of the CSF-1R.
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Affiliation(s)
- David P Sester
- Cooperative Research Centre for Chronic Inflammatory Diseases, Institute for Molecular Bioscience, University of Queensland, Brisbane, Queensland 4072, Australia
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21
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Wang Y, Keogh RJ, Hunter MG, Mitchell CA, Frey RS, Javaid K, Malik AB, Schurmans S, Tridandapani S, Marsh CB. SHIP2 Is Recruited to the Cell Membrane upon Macrophage Colony-Stimulating Factor (M-CSF) Stimulation and Regulates M-CSF-Induced Signaling. THE JOURNAL OF IMMUNOLOGY 2004; 173:6820-30. [PMID: 15557176 DOI: 10.4049/jimmunol.173.11.6820] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The Src homology 2-containing inositol phosphatase SHIP1 functions in hemopoietic cells to limit activation events mediated by PI3K products, including Akt activation and cell survival. In contrast to the limited cellular expression of SHIP1, the related isoform SHIP2, is widely expressed in both parenchymal and hemopoietic cells. The goal of this study was to determine how SHIP2 functions to regulate M-CSF signaling. We report that 1) SHIP2 was tyrosine-phosphorylated in M-CSF-stimulated human alveolar macrophages, human THP-1 cells, murine macrophages, and the murine macrophage cell line RAW264; 2) SHIP2 associated with the M-CSF receptor after M-CSF stimulation; and 3) SHIP2 associated with the actin-binding protein filamin and localization to the cell membrane, requiring the proline-rich domain, but not on the Src homology 2 domain of SHIP2. Analyzing the function of SHIP2 in M-CSF-stimulated cells by expressing either wild-type SHIP2 or an Src homology 2 domain mutant of SHIP2 reduced Akt activation in response to M-CSF stimulation. In contrast, the expression of a catalytically deficient mutant of SHIP2 or the proline-rich domain of SHIP2 enhanced Akt activation. Similarly, the expression of wild-type SHIP2 inhibited NF-kappaB-mediated gene transcription. Finally, fetal liver-derived macrophages from SHIP2 gene knockout mice enhanced activation of Akt in response to M-CSF treatment. These data suggest a novel regulatory role for SHIP2 in M-CSF-stimulated myeloid cells.
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Affiliation(s)
- Yijie Wang
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, and The Dorothy M. Davis Heart and Lung Research Institute, Ohio State University, Columbus, OH 43210, USA
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22
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Tagoh H, Schebesta A, Lefevre P, Wilson N, Hume D, Busslinger M, Bonifer C. Epigenetic silencing of the c-fms locus during B-lymphopoiesis occurs in discrete steps and is reversible. EMBO J 2004; 23:4275-85. [PMID: 15483629 PMCID: PMC524389 DOI: 10.1038/sj.emboj.7600421] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2004] [Accepted: 08/30/2004] [Indexed: 01/07/2023] Open
Abstract
The murine c-fms (Csf1r) gene encodes the macrophage colony-stimulating factor receptor, which is essential for macrophage development. It is expressed at a low level in haematopoietic stem cells and is switched off in all non-macrophage cell types. To examine the role of chromatin structure in this process we studied epigenetic silencing of c-fms during B-lymphopoiesis. c-fms chromatin in stem cells and multipotent progenitors is in the active conformation and bound by transcription factors. A similar result was obtained with specified common myeloid and lymphoid progenitor cells. In developing B cells, c-fms chromatin is silenced in distinct steps, whereby first the binding of transcription factors and RNA expression is lost, followed by a loss of nuclease accessibility. Interestingly, regions of de novo DNA methylation in B cells overlap with an intronic antisense transcription unit that is differently regulated during lymphopoiesis. However, even at mature B cell stages, c-fms chromatin is still in a poised conformation and c-fms expression can be re-activated by conditional deletion of the transcription factor Pax5.
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Affiliation(s)
- Hiromi Tagoh
- Molecular Medicine Unit, St James's University Hospital, University of Leeds, Leeds, UK
| | - Alexandra Schebesta
- Research Institute of Molecular Pathology, Vienna Biocenter, Vienna, Austria
| | - Pascal Lefevre
- Molecular Medicine Unit, St James's University Hospital, University of Leeds, Leeds, UK
| | - Nicola Wilson
- Molecular Medicine Unit, St James's University Hospital, University of Leeds, Leeds, UK
| | - David Hume
- Institute for Molecular Bioscience, University of Queensland, Queensland, Australia
| | - Meinrad Busslinger
- Research Institute of Molecular Pathology, Vienna Biocenter, Vienna, Austria
| | - Constanze Bonifer
- Molecular Medicine Unit, St James's University Hospital, University of Leeds, Leeds, UK
- Molecular Medicine Unit, St James's University Hospital, University of Leeds, Leeds LS9 7TF, UK. Tel.: +44 113 206 5676; Fax: +44 113 244 4475; E-mail:
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23
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Burnett SH, Kershen EJ, Zhang J, Zeng L, Straley SC, Kaplan AM, Cohen DA. Conditional macrophage ablation in transgenic mice expressing a Fas-based suicide gene. J Leukoc Biol 2004; 75:612-23. [PMID: 14726498 DOI: 10.1189/jlb.0903442] [Citation(s) in RCA: 220] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Transgenic mice expressing an inducible suicide gene, which allows systemic and reversible elimination of macrophages, were developed. A macrophage-specific c-fms promoter was used to express enhanced green fluorescent protein and a drug-inducible suicide gene that leads to Fas-mediated apoptosis in resting and cycling cells of the macrophage lineage. Transgenic mice were fertile, of normal weight, and showed no abnormal phenotype before drug exposure. The transgene was expressed constitutively in macrophages and dendritic cells (DC) but not significantly in T cells or B cells. Induction of the suicide gene led to depletion of 70-95% of macrophages and DC in nearly all tissues examined. Depletion reduced the ability to clear bacteria from the blood and led to increased bacterial growth in the liver. Depleted mice displayed several abnormalities, including splenomegaly, lymphadenopathy, thymic atrophy, extramedullary hematopoiesis, and development of peritoneal adhesions. This new, transgenic line will be useful in investigating the role of macrophages and DC.
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MESH Headings
- Animals
- Apoptosis/drug effects
- Apoptosis/genetics
- Bacterial Infections/genetics
- Bacterial Infections/immunology
- Bacterial Infections/physiopathology
- Cell Count
- Cells, Cultured
- Dendritic Cells/cytology
- Dendritic Cells/drug effects
- Dendritic Cells/metabolism
- Dimerization
- Disease Models, Animal
- Genes, Transgenic, Suicide/drug effects
- Genes, Transgenic, Suicide/genetics
- Green Fluorescent Proteins
- Immunity, Cellular/genetics
- Luminescent Proteins
- Macrophages/cytology
- Macrophages/drug effects
- Macrophages/metabolism
- Mice
- Mice, Inbred C57BL
- Mice, Transgenic
- Promoter Regions, Genetic/genetics
- Receptor, Macrophage Colony-Stimulating Factor/genetics
- Receptors, Nerve Growth Factor/genetics
- Tacrolimus/analogs & derivatives
- Tacrolimus/pharmacology
- Tacrolimus Binding Proteins/genetics
- fas Receptor/genetics
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Affiliation(s)
- Sandra H Burnett
- Department of Microbiology, University of Kentucky College of Medicine, Lexington, Kentucky 40536-0084, USA
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24
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Sasmono RT, Oceandy D, Pollard JW, Tong W, Pavli P, Wainwright BJ, Ostrowski MC, Himes SR, Hume DA. A macrophage colony-stimulating factor receptor-green fluorescent protein transgene is expressed throughout the mononuclear phagocyte system of the mouse. Blood 2003; 101:1155-63. [PMID: 12393599 DOI: 10.1182/blood-2002-02-0569] [Citation(s) in RCA: 498] [Impact Index Per Article: 23.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The c-fms gene encodes the receptor for macrophage colony-stimulating factor (CSF-1). The gene is expressed selectively in the macrophage and trophoblast cell lineages. Previous studies have indicated that sequences in intron 2 control transcript elongation in tissue-specific and regulated expression of c-fms. In humans, an alternative promoter was implicated in expression of the gene in trophoblasts. We show that in mice, c-fms transcripts in trophoblasts initiate from multiple points within the 2-kilobase (kb) region flanking the first coding exon. A reporter gene construct containing 3.5 kb of 5' flanking sequence and the downstream intron 2 directed expression of enhanced green fluorescent protein (EGFP) to both trophoblasts and macrophages. EGFP was detected in trophoblasts from the earliest stage of implantation examined at embryonic day 7.5. During embryonic development, EGFP highlighted the large numbers of c-fms-positive macrophages, including those that originate from the yolk sac. In adult mice, EGFP location was consistent with known F4/80-positive macrophage populations, including Langerhans cells of the skin, and permitted convenient sorting of isolated tissue macrophages from disaggregated tissue. Expression of EGFP in transgenic mice was dependent on intron 2 as no lines with detectable EGFP expression were obtained where either all of intron 2 or a conserved enhancer element FIRE (the Fms intronic regulatory element) was removed. We have therefore defined the elements required to generate myeloid- and trophoblast-specific transgenes as well as a model system for the study of mononuclear phagocyte development and function.
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Affiliation(s)
- R Tedjo Sasmono
- Institute for Molecular Bioscience and ARC Special Research Centre for Functional and Applied Genomics, University of Queensland, Brisbane, Australia
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25
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Hume DA, Ross IL, Himes SR, Sasmono RT, Wells CA, Ravasi T. The mononuclear phagocyte system revisited. J Leukoc Biol 2002. [DOI: 10.1189/jlb.72.4.621] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Affiliation(s)
- David A. Hume
- Institute for Molecular Bioscience, University of Queensland, Australia
| | - Ian L. Ross
- Institute for Molecular Bioscience, University of Queensland, Australia
| | - S. Roy Himes
- Institute for Molecular Bioscience, University of Queensland, Australia
| | - R. Tedjo Sasmono
- Institute for Molecular Bioscience, University of Queensland, Australia
| | | | - Timothy Ravasi
- Institute for Molecular Bioscience, University of Queensland, Australia
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26
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Rudge TL, Johnson LF. Synergistic activation of the TATA-less mouse thymidylate synthase promoter by the Ets transcription factor GABP and Sp1. Exp Cell Res 2002; 274:45-55. [PMID: 11855856 DOI: 10.1006/excr.2001.5451] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The mouse thymidylate synthase (TS) promoter lacks a TATA box and an initiator element and directs transcriptional initiation at multiple sites over a 90-nucleotide region. The minimum sequence required for wild-type promoter activity has been mapped to a 30-nucleotide essential promoter region that partially overlaps the 5' end of the transcriptional initiation window. The essential promoter region contains two potential binding sites for members of the Ets family of transcription factors as well as a binding site for Sp1. Promoter mutation analyses revealed that all three of these sites are important for promoter activity. Transient cotransfection assays showed that GABP, a heterodimeric Ets factor, is able to stimulate expression of reporter genes driven by the wild-type mouse TS promoter whereas several other Ets factors have no effect. Electrophoretic mobility shift assays revealed that recombinant GABP binds to both Ets elements in the essential promoter region. Stimulation of promoter activity by GABP is diminished when either Ets element is inactivated and is prevented when both Ets elements are inactivated. Transient cotransfection assays revealed that Sp1 and GABP stimulate TS promoter activity in a highly synergistic manner.
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Affiliation(s)
- Thomas L Rudge
- Department of Molecular Genetics, The Ohio State University, Columbus, Ohio 43210, USA
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27
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Xie Y, Chen C, Stevenson MA, Hume DA, Auron PE, Calderwood SK. NF-IL6 and HSF1 have mutually antagonistic effects on transcription in monocytic cells. Biochem Biophys Res Commun 2002; 291:1071-80. [PMID: 11866474 DOI: 10.1006/bbrc.2002.6562] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We have examined the functional antagonism between the regulator of the heat shock response, HSF1, and NF-IL6, which plays a major role in control of the acute phase response (APR). Agents that activate HSF1 such as heat shock and sodium salicylate inhibit NF-IL6 induced transcription while NF-IL6 activators such as lipopolysaccharide (LPS) and interleukin 6 (IL-6) repressed the stress responsive HSP70B promoter. In transfection studies, the inhibitory effects of HSF1 and NF-IL6 on the c-fms promoter were shown to be highly dose-dependent. Furthermore, heat shock is inhibitory to differentiation-linked expression of macrophage colony stimulating factor (M-CSF) receptor, product of the c-fms gene, which is transcriptionally activated by NF-IL6 but repressed by HSF1. Our studies suggest a strong mutual antagonism between the heat shock response and APR, which may influence the sensitivity and duration of inflammatory responses.
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Affiliation(s)
- Yue Xie
- Department of Radiation Oncology, Dana Farber Cancer Institute, Harvard Medical School, 44 Binney Street, Boston, Massachusetts 02115, USA
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28
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Ping YH, Rana TM. DSIF and NELF interact with RNA polymerase II elongation complex and HIV-1 Tat stimulates P-TEFb-mediated phosphorylation of RNA polymerase II and DSIF during transcription elongation. J Biol Chem 2001; 276:12951-8. [PMID: 11112772 DOI: 10.1074/jbc.m006130200] [Citation(s) in RCA: 155] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Control of transcription elongation requires a complex interplay between the recently discovered positive transcription elongation factor b (P-TEFb) and negative transcription elongation factors, 5,6-dichloro-1-beta-d-ribofuranosylbenzimidazole (DRB) sensitivity inducing factors (DSIF) and the negative elongation factor (NELF). Activation of HIV-1 gene expression is regulated by a nascent RNA structure, termed TAR RNA, in concert with HIV-1 Tat protein and these positive and negative elongation factors. We have used a stepwise RNA pol II walking approach and Western blotting to determine the dynamics of interactions between HIV-1 Tat, DSIF/NELF, and the transcription complexes actively engaged in elongation. In addition, we developed an in vitro kinase assay to determine the phosphorylation status of proteins during elongation stages. Our results demonstrate that DSIF/NELF associates with RNA pol II complexes during early transcription elongation and travels with elongation complexes as the nascent RNA is synthesized. Our results also show that HIV-1 Tat protein stimulated DSIF and RNA pol II phosphorylation by P-TEFb during elongation. These findings reveal a molecular mechanism for the negative and positive regulation of transcriptional elongation at the HIV-1 promoter.
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Affiliation(s)
- Y H Ping
- Department of Pharmacology, Robert Wood Johnson Medical School, and Molecular Biosciences Graduate Program at Rutgers University, Piscataway, New Jersey 08854, USA
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29
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Abstract
To review the data on the origins, phenotype, and function of embryonic phagocytes that has accumulated over past decade. Most of the relevant articles were selected based on the PubMed database entries. In additional, the Interactive Fly database (http://sdb.bio. purdue.edu/fly/aimain/1aahome.htm), FlyBase (http://flybase.bio. indiana.edu:82/), and TBase (http://tbase.jax.org/) were used to search for relevant information and articles. Phagocytes in a vertebrate embryo develop in two sites (yolk sac and liver) and contribute to organogenesis in part through their ability to recognize and clear apoptotic cells. Yolk sac-derived phagocytes differ in differentiation pathway and marker gene expression from macrophages produced via classic hematopoietic progenitors in the liver. We argue that yolk sac-derived phagocytes constitute a separate cell lineage. This conclusion raises the question of whether primitive phagocytes persist into the adulthood.
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Affiliation(s)
- A M Lichanska
- Departments of Medical Genetics and Ophthalmology, Queen's University of Belfast, Belfast, United Kingdom
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30
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Wang MH, Fung HL, Chen YQ. Regulation of the RON receptor tyrosine kinase expression in macrophages: blocking the RON gene transcription by endotoxin-induced nitric oxide. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2000; 164:3815-21. [PMID: 10725742 DOI: 10.4049/jimmunol.164.7.3815] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Previous studies have shown that activation of the RON receptor tyrosine kinase inhibits inducible NO production in murine peritoneal macrophages. The purpose of this study is to determine whether inflammatory mediators such as LPS, IFN-gamma, and TNF-alpha regulate RON expression. Western blot analysis showed that RON expression is reduced in peritoneal macrophages collected from mice injected with a low dose of LPS. The inhibition was seen as early as 8 h after LPS challenge. Experiments in vitro also demonstrated that the levels of the RON mRNA and protein are diminished in cultured peritoneal macrophages following LPS stimulation. TNF-alpha plus IFN-gamma abrogated macrophage RON expression, although individual cytokines had no significant effect. Because LPS and TNF-alpha plus IFN-gamma induce NO production, we reasoned that NO might be involved in the RON inhibition. Two NO donors, S-nitroglutathione (GSNO) and (+/-)-S-nitroso-N-acetylpenicillamine (SNAP), directly inhibited macrophage RON expression when added to the cell cultures. Blocking NO production by NO inhibitors like TGF-beta prevented the LPS-mediated inhibitory effect. In Raw264.7 cells transiently transfected with a report vector, GSNO or SNAP inhibited the luciferase activities driven by the RON gene promoter. Moreover, GSNO or SNAP inhibited the macrophage-stimulating protein-induced RON phosphorylation and macrophage migration. We concluded from these data that RON expression in macrophages is regulated during inflammation. LPS and TNF-alpha plus IFN-gamma are capable of down-regulating RON expression through induction of NO production. The inhibitory effect of NO is mediated by suppression of the RON gene promoter activities.
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MESH Headings
- Animals
- Cell Line
- Cell Movement/immunology
- Enzyme Inhibitors/pharmacology
- Growth Substances/pharmacology
- Hepatocyte Growth Factor
- Injections, Intraperitoneal
- Lipopolysaccharides/administration & dosage
- Lipopolysaccharides/immunology
- Macrophages, Peritoneal/enzymology
- Macrophages, Peritoneal/immunology
- Macrophages, Peritoneal/metabolism
- Mice
- Mice, Inbred C3H
- Nitric Oxide/biosynthesis
- Nitric Oxide/immunology
- Nitric Oxide Donors/pharmacology
- Nitric Oxide Synthase/antagonists & inhibitors
- Nitric Oxide Synthase Type II
- Phosphorylation
- Promoter Regions, Genetic/immunology
- Proto-Oncogene Proteins
- RNA, Messenger/antagonists & inhibitors
- RNA, Messenger/biosynthesis
- Receptor Protein-Tyrosine Kinases/antagonists & inhibitors
- Receptor Protein-Tyrosine Kinases/biosynthesis
- Receptor Protein-Tyrosine Kinases/genetics
- Receptor Protein-Tyrosine Kinases/metabolism
- Receptors, Cell Surface/antagonists & inhibitors
- Receptors, Cell Surface/biosynthesis
- Receptors, Cell Surface/genetics
- Receptors, Cell Surface/metabolism
- Transcription, Genetic/immunology
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Affiliation(s)
- M H Wang
- Division of Pulmonary Sciences and Critical Care Medicine, Department of Medicine, University of Colorado School of Medicine, Denver, CO 80204, USA.
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31
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Abstract
The macrophage cell lineage continually arises from hematopoietic stem cells during embryonic, fetal, and adult life. Previous theories proposed that macrophages are the recent progeny of bone marrow-derived monocytes and that they function primarily in phagocytosis. More recently, however, observations have shown that the ontogeny of macrophages in early mouse and human embryos is different from that occurring during adult development, and that the embryonic macrophages do not follow the monocyte pathway. Fetal macrophages are thought to differentiate from yolk sac-derived primitive macrophages before the development of adult monocytes. Further support for a separate lineage of fetal macrophages has come from studies of several species, including chicken, zebrafish, Xenopus, Drosophila, and C. elegans. The presence of fetal macrophages in PU.1-null mice indicates their independence from monocyte precursors and their existence as an alternative macrophage lineage.
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Affiliation(s)
- J L Shepard
- Children's Hospital, Department of Medicine, Boston, Massachusetts 02115, USA
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32
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Sester DP, Beasley SJ, Sweet MJ, Fowles LF, Cronau SL, Stacey KJ, Hume DA. Bacterial/CpG DNA Down-Modulates Colony Stimulating Factor-1 Receptor Surface Expression on Murine Bone Marrow-Derived Macrophages with Concomitant Growth Arrest and Factor-Independent Survival. THE JOURNAL OF IMMUNOLOGY 1999. [DOI: 10.4049/jimmunol.163.12.6541] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Abstract
Unmethylated CpG motifs within bacterial DNA constitute a pathogen-associated molecular pattern recognized by the innate immune system. Many of the immunomodulatory functions of bacterial DNA can be ascribed to the ability to activate macrophages and dendritic cells. Here we show stimulatory DNA, like LPS, caused growth arrest of murine bone marrow-derived macrophages proliferating in CSF-1. Stimulatory DNA caused selective down-modulation of CSF-1 receptor surface expression. Flow cytometric analysis of CSF-1-deprived bone marrow-derived macrophages revealed that in contrast to the synchronous reduction of CSF-1 receptor upon CSF-1 addition, activating DNA (both bacterial DNA and CpG-containing oligonucleotide) caused rapid removal of receptor from individual cells leading to a bimodal distribution of surface expression at intermediate times or submaximal doses of stimulus. Despite causing growth arrest, both stimulatory DNA and LPS promoted factor-independent survival of bone marrow-derived macrophages, which was associated with phosphorylation of the mitogen-activated protein kinase family members, extracellular-regulated kinase 1 and 2. CSF-1 receptor down-modulation may polarize the professional APC compartment to the more immunostimulatory dendritic cell-like phenotype by suppressing terminal macrophage differentiation mediated by CSF-1.
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Affiliation(s)
- David P. Sester
- *Center for Molecular and Cellular Biology, University of Queensland, Queensland, Australia; and
- †Departments of Microbiology and Parasitology and Biochemistry, University of Queensland, Australia
| | - Shannon J. Beasley
- *Center for Molecular and Cellular Biology, University of Queensland, Queensland, Australia; and
- †Departments of Microbiology and Parasitology and Biochemistry, University of Queensland, Australia
| | - Matthew J. Sweet
- *Center for Molecular and Cellular Biology, University of Queensland, Queensland, Australia; and
- †Departments of Microbiology and Parasitology and Biochemistry, University of Queensland, Australia
| | - Lindsay F. Fowles
- *Center for Molecular and Cellular Biology, University of Queensland, Queensland, Australia; and
| | - Stephen L. Cronau
- *Center for Molecular and Cellular Biology, University of Queensland, Queensland, Australia; and
- †Departments of Microbiology and Parasitology and Biochemistry, University of Queensland, Australia
| | - Katryn J. Stacey
- *Center for Molecular and Cellular Biology, University of Queensland, Queensland, Australia; and
- †Departments of Microbiology and Parasitology and Biochemistry, University of Queensland, Australia
| | - David A. Hume
- *Center for Molecular and Cellular Biology, University of Queensland, Queensland, Australia; and
- †Departments of Microbiology and Parasitology and Biochemistry, University of Queensland, Australia
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33
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Kleene R, Zdzieblo J, Wege K, Kern HF. A novel zymogen granule protein (ZG29p) and the nuclear protein MTA1p are differentially expressed by alternative transcription initiation in pancreatic acinar cells of the rat. J Cell Sci 1999; 112 ( Pt 15):2539-48. [PMID: 10393810 DOI: 10.1242/jcs.112.15.2539] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Using a polyclonal antibody against purified zymogen granule membrane components from rat pancreas a cDNA coding for the 29 kDa protein (ZG29p) was identified by immunoscreening of a hormonally stimulated pancreas cDNA library. Western blot analysis suggests that ZG29p is a pancreas-specific protein and immunofluorescence shows that ZG29p is mainly associated with zymogen granules. Analysis of subcellular fraction applying immunoblotting revealed that ZG29p was localized mainly in the soluble fraction of zymogen granules and in a Golgi- and RER-enriched fraction, but was absent from the cytosol. In isolated zymogen granule content ZG29p was associated with protein complexes containing amylase as main constituent. The cDNA coding for ZG29p is homologous to the C-terminal region of the candidate metastasis-associated gene mta1. Northern blot analysis and RT-PCR showed that no MTA1 mRNA is present in pancreas from fasted rats and in the rat pancreas carcinoma cell line AR4-2J in its protodifferentiated state. Although no ZG29p specific mRNA was seen in the northern blot analysis, RT-PCR showed that ZG29p was expressed under both non-stimulated and stimulated conditions. The expression of MTA1 was up-regulated in the pancreas by endogenous cholecystokinin release and in AR4-2J after induction of cellular differentiation by dexamethasone. Western blotting and immunofluorescense studies indicated that MTA1p is localized in the nucleus in all tissues studied. Using genomic DNA in PCR analysis it was shown that two short introns are present flanking the sequences of the 5'end of ZG29p cDNA. One intron contains consensus elements required for pancreas specific transcription initiation, suggesting that MTA1 and ZG29 are differentially expressed by alternative transcription initiation in the pancreas. The localisation of MTA1p in the nucleus of most cell types could signify a general role in gene regulation, while the cell type specific and exclusive expression of ZG29p in pancreatic acinar cells could indicate a role in granule formation.
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Affiliation(s)
- R Kleene
- Department of Cell Biology and Cell Pathology, Philipps University, Marburg/Germany.
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34
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Differentiation of the Mononuclear Phagocyte System During Mouse Embryogenesis: The Role of Transcription Factor PU.1. Blood 1999. [DOI: 10.1182/blood.v94.1.127.413k07_127_138] [Citation(s) in RCA: 131] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
During mouse embryogenesis, macrophage-like cells arise first in the yolk sac and are produced subsequently in the liver. The onset of liver hematopoiesis is associated with the transition from primitive to definitive erythrocyte production. This report addresses the hypothesis that a similar transition in phenotype occurs in myelopoiesis. We have used whole mount in situ hybridization to detect macrophage-specific genes expressed during mouse development. The mouse c-fms mRNA, encoding the receptor for macrophage colony-stimulating factor (CSF-1), was expressed on phagocytic cells in the yolk sac and throughout the embryo before the onset of liver hematopoiesis. Similar cells were detected using the mannose receptor, the complement receptor (CR3), or the Microphthalmia transcription factor (MITF) as mRNA markers. By contrast, other markers including the F4/80 antigen, the macrophage scavenger receptor, the S-100 proteins, S100A8 and S100A9, and the secretory product lysozyme appeared later in development and appeared restricted to only a subset of c-fms–positive cells. Two-color immunolabeling on disaggregated cells confirmed that CR3 and c-fmsproteins are expressed on the same cells. Among the genes appearing later in development was the macrophage-restricted transcription factor, PU.1, which has been shown to be required for normal adult myelopoiesis. Mice with null mutations in PU.1 had normal numbers of c-fms–positive phagocytes at 11.5dpc. PU.1(−/−) embryonic stem cells were able to give rise to macrophage-like cells after cultivation in vitro. The results support previous evidence that yolk sac–derived fetal phagocytes are functionally distinct from those arising in the liver and develop via a different pathway.
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35
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Kitami Y, Fukuoka T, Okura T, Takata Y, Maguchi M, Igase M, Kohara K, Hiwada K. Molecular structure and function of rat platelet-derived growth factor beta-receptor gene promoter. J Hypertens 1998; 16:437-45. [PMID: 9797189 DOI: 10.1097/00004872-199816040-00005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE To understand the regulatory mechanism of platelet-derived growth factor beta-receptor gene expression. METHODS A 1.7 kb genomic fragment was obtained from a rat genomic library. After we had determined an entire sequence of this fragment, transcription start sites were determined both by primer extension analysis and by riboprobe mapping. We performed a functional promoter assay by using a dual-luciferase reporter system. Progressive 5'-deletions of the fragment and site-directed mutagenesis for the CCAAT motif located at -67 or -94 were used for the assay, and their promoter activities in vascular smooth muscle cells were assessed. Gel-mobility shift analysis was also performed for the CCAAT motif at -67. Effects of the upstream sequence spanning -310 through -120 on heterologous gene promoters were also investigated. RESULTS Multiple transcription start sites were observed in the 5'-flanking region, and the 1.7 kb sequence was actually active as a functional promoter in vascular smooth muscle cells. Two important sequences responsible for the basal transcriptional activity were identified by the functional promoter assay. One was the CCAAT motif at -67 which acts as a promoter itself, and the other was the upstream region spanning -310 through -210 which positively regulates the basal promoter activity. CONCLUSION The basal promoter activity of the rat platelet-derived growth factor beta-receptor gene is mainly regulated by the interaction or coordination of two sequences, the CCAAT motif and the upstream control element.
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Affiliation(s)
- Y Kitami
- The Second Department of Internal Medicine, Ehime University School of Medicine, Japan.
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36
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Ross IL, Yue X, Ostrowski MC, Hume DA. Interaction between PU.1 and another Ets family transcription factor promotes macrophage-specific Basal transcription initiation. J Biol Chem 1998; 273:6662-9. [PMID: 9506963 DOI: 10.1074/jbc.273.12.6662] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Numerous macrophage-restricted promoters lack TATA boxes or other conventional initiation motifs but contain high affinity binding sites (PU boxes) for the macrophage-restricted Ets family transcription factor PU.1. In RAW264 murine macrophages, multimerized PU boxes were not active as enhancers when placed upstream of a minimal promoter. To model their role in basal promoters, we inserted PU boxes into a promoterless luciferase reporter plasmid. Two sites, regardless of orientation, were necessary and sufficient to direct reporter gene expression in transient transfections of the RAW264 macrophage-like cell line. This activity was absent in transfected 3T3 fibroblasts but could be induced by PU.1 coexpression. Both the model promoter and the macrophage-specific mouse and human c-fms promoters were activated in RAW264 cells by other Ets family transcription factors, Ets-2 and Elf-1. In fibroblasts, the effects of PU.1 and Ets-2 were multiplicative, whereas overexpression of PU.1 in RAW264 cells reduced activation of c-fms or model promoters by the other Ets factors. The PU.1 and Ets-2 binding sites of the mouse c-fms promoter have been located by DNase footprinting. A conserved Ets-like motif at the transcription site, CAGGAAC, that bound only weakly to PU.1, was identified as an additional critical basal c-fms promoter element. Comparison of studies on the model promoter, c-fms and other myeloid promoters provides evidence for a conserved mechanism that involves three separate and functionally distinct Ets-like motifs.
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Affiliation(s)
- I L Ross
- Department of Microbiology, University of Queensland, Brisbane 4072, Australia
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37
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Intron-exon structures. ACTA ACUST UNITED AC 1998. [DOI: 10.1016/s1067-5701(98)80020-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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38
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Harrison L, Ascione AG, Takiguchi Y, Wilson DM, Chen DJ, Demple B. Comparison of the promoters of the mouse (APEX) and human (APE) apurinic endonuclease genes. Mutat Res 1997; 385:159-72. [PMID: 9506886 DOI: 10.1016/s0921-8777(97)00053-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
We investigated the minimal promoter of APEX, which encodes mouse apurinic DNA repair endonuclease. A 1.85-kb fragment with APEX upstream sequences and approximately 290 bp of the transcribed region linked to a chloramphenicol acetyltransferase (CAT) reporter gene was assayed by transient transfection in NIH-3T3 cells. The minimal APEX promoter was comprised of approximately 190 bp of upstream and approximately 170 bp of transcribed DNA (exon 1 and most of intron 1). This approximately 360-bp region contains two CCAAT boxes and other consensus protein binding sites, but no TATA box. Deletion of the 5'-most CCAAT box decreased activity approximately 5-fold. The second CCAAT box (situated in exon 1) may play an independent role in APEX expression. Transcription start sites have been identified downstream of the second CCAAT box, and DNase I footprinting demonstrated NIH-3T3 nuclear proteins binding this region, including an Spl site located between the CCAAT boxes. Electrophoretic mobility-shift assays indicated binding by purified Sp1. Mouse proteins did not bind three myc-like (USF) sites in the APEX promoter, in contrast to the APE promoter. The APEX and APE promoter had similar activity in Hela cells, but in mouse cells, the murine promoter had approximately 5-fold higher activity than did the human promoter. Both the APEX and APE promoters exhibited bidirectional activity in their cognate cells.
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Affiliation(s)
- L Harrison
- Department of Cancer Cell Biology, Harvard School of Public Health, Boston, MA 02115, USA
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39
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Kamdar SJ, Fuller JA, Evans R. CSF-1-induced and constitutive Il6 gene expression in mouse macrophages: evidence for PKC-dependent and -independent pathways. Exp Cell Res 1997; 232:439-42. [PMID: 9168824 DOI: 10.1006/excr.1997.3551] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
It has been recently shown that CSF-1 enhanced the constitutive expression of the Il6 gene in resident mouse peritoneal macrophages (PM phi) but little is known about the pathways involved. In this report, we show that both constitutive and CSF-1-induced IL-6 release were enhanced and prolonged in the presence of the PKC inhibitors, staurosporine (SP) and its derivative, GF-109203X. Enhancement of constitutive IL-6 release required higher concentrations of inhibitors, while enhanced CSF-1-induced release was diminished when inhibitor concentrations exceeded defined limits. SP was also shown to activate constitutive IL-6 release by blood monocytes and elicited PM phi but had no effect on their responsiveness to CSF-1. Activation of PKC by exposure of resident PM phi to phorbol myristate acetate (PMA) also resulted in enhanced IL-6 release and PMA was shown to synergize with CSF-1. These data indicate that CSF-1 does not induce Il6 gene expression by amplifying the constitutive pathway in all mononuclear phagocyte subpopulations. It exerts its effects independently of PKC, which may activate Il6 gene expression in its own right by an alternative pathway. While CSF-1 and PKC are involved in separate pathways, the synergistic IL-6 response seen when PMA and CSF-1 interact suggests convergence of the two pathways. It is also apparent that multiple PKs, excluding PKC, may be involved in repressing constitutive and CSF-1-induced Il6 gene expression.
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Affiliation(s)
- S J Kamdar
- Jackson Laboratory, Bar Harbor, Maine 04609, USA
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40
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Tkachuk M, Gisler RH. The promoter of macrophage colony-stimulating factor receptor is active in astrocytes. Neurosci Lett 1997; 225:121-5. [PMID: 9147389 DOI: 10.1016/s0304-3940(97)00186-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Macrophage colony-stimulating factor (M-CSF) is a hematopoietin whose actions are essential for growth and survival of macrophages, placental development, ramification of microglia and tumor progression. The expression of the receptor for macrophage colony-stimulating factor (c-fms) is regulated by two distinct promoters: distal and proximal. The distal promoter is active in trophoblasts during embryogenesis and the proximal promoter directs expression to the cells of myeloid lineage. Here we report the generation of transgenic mice expressing beta-galactosidase under the control of the human proximal c-fms promoter and demonstrate the promoter activity in astrocytes, cells of neurological origin that partially take over the role of the macrophages in the central nervous system. Enzymatic activity of beta-galactosidase was detected in homogenated spleen, bone marrow and brain and in the cell extracts from peritoneal macrophages of transgenic mice. Immunohistochemical staining of brain showed the presence of beta-galactosidase in astrocytes. We hypothesize that M-CSF released by astrocytes, upon stimulation by lipopolysaccharide (LPS), tumor necrosis factor alpha (TNF alpha) or interleukin-1 (IL-1), regulates the expression of its own receptor.
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Affiliation(s)
- M Tkachuk
- PRPG, Hofmann-La Roche AG, Basel, Switzerland
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41
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Igarashi H, Tsuzuki T, Kakuma T, Tominaga Y, Sekiguchi M. Organization and expression of the mouse MTH1 gene for preventing transversion mutation. J Biol Chem 1997; 272:3766-72. [PMID: 9013634 DOI: 10.1074/jbc.272.6.3766] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
An enzyme, 8-oxo-7,8-dihydrodeoxyguanosine triphosphatase (8-oxo-dGTPase), is present in various organisms and plays an important role in the control of spontaneous mutagenesis. The enzyme hydrolyzes 8-oxo-dGTP, an oxidized form of dGTP, to 8-oxo-dGMP, thereby preventing the occurrence of A:T to C:G transversion, caused by misincorporation. We isolated the mouse genomic sequence encoding the enzyme and elucidated its structure. The gene, named MTH1 for mutT homologue 1, is composed of at least five exons and spans approximately 9 kilobase pairs. A genomic region containing the pseudogene was also isolated. The promoter region for the gene is GC-rich, contains many AP-1 and AP-2 recognition sequences, and lacks a typical TATA box. Primer extension and S1 mapping analyses revealed the existence of multiple transcription initiation sites, among which a major site was defined as +1. The putative promoter region was placed upstream of the chloramphenicol acetyltransferase reporter gene, and control of expression of the gene was examined by introducing the construct into mouse NIH 3T3 cells. Deletion analysis indicated that a sequence from -321 to +9 carries the basic promoter activity while an adjacent region, spanning from +352 to +525 stimulates the frequency of transcription.
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Affiliation(s)
- H Igarashi
- Department of Biochemistry, Medical Institute of Bioregulation, Kyushu University, Fukuoka 812-82, Japan
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42
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Abstract
The PDGFbeta r gene has been implicated in many physiological processes including development and wound healing. Aberrant expression of the receptor is seen in many pathological conditions such as atherosclerosis and inflammatory diseases. To study the mechanisms of PDGFbeta r regulation, we identified the regulatory regions of the gene. We have cloned and characterized the promoter region of the platelet-derived growth factor beta receptor (PDGFbeta r). We isolated a 4.5 Kb genomic fragment which confers PDGFbeta r tissue-specific promoter activity. This fragment can direct transcription of a luciferase reporter gene in a cell-specific manner which correlates well with the known pattern of expression of the PDGFbeta r. The specificity of this clone was demonstrated by its high activity in NIH 3T3 fibroblasts and lack of activity in N-MUNG epithelial cells, a pattern that parallels the expression of the endogenous PDGFbeta r. We have defined a 614 bp region encompassing the 5' untranslated region of the gene which includes the basal promoter region. We generated transgenic mice that carry the chloramphenicol acetyltransferase (CAT) reporter gene under the control of the 4.5 Kb promoter. The expression pattern of the reporter gene was compared to that of the endogenous PDGFbeta r gene. The promoter was able to direct reporter gene expression with the same temporal and spatial pattern as the endogenous PDGFbeta r. The most prominent expression was in condensing mesenchyme of developing blood vessels, bone and tissues adjacent to epithelium. We conclude that this clone contains the regulatory regions sufficient to direct expression of the PDGFbeta r. The further analysis of this promoter will help elucidate the transcriptional regulation of expression of the PDGFbeta r, and provide a useful tool for directing expression of heterologous genes.
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Affiliation(s)
- E Shinbrot
- Daiichi Research Center, Cardiovascular Research Institute, University of California, San Francisco 94143-0130, USA
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43
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Abstract
Cells of the mononuclear phagocyte lineage possess receptors for macrophage colony-stimulating factor (CSF-1) encoded by the c-fms protooncogene and respond to CSF-1 with increased survival, growth, differentiation, and reversible changes in function. The c-fms gene is itself a macrophage differentiation marker. In whole mount analyses of mRNA expression in embryos, c-fms is expressed at very high levels on placental trophoblasts. It is detectable on individual cells in the yolk sac around 8.5 to 9 days postcoitus, appears on isolated cells in the head of the embryo around 9.5 dpc, and appears on numerous cells throughout the embryo by day 10.5. The extent of c-fms expression is much greater than for other macrophage-specific genes including lysozyme and a macrophage-specific protein tyrosine phosphatase. Our studies of the cis-acting elements of the c-fms promoter have indicated a key role for collaboration between the macrophage-specific transcription factor, Pu.1, which functions in determining the site of transcription initiation, and other members of the Ets transcription factor family. This is emerging as a common pattern in macrophage-specific promoters. We have shown that two PU box elements alone can function as a macrophage-specific promoter. The activity of both the artificial promoter and the c-fms promoter is activated synergistically by coexpression of Pu.1 and another Ets factor, c-Ets-2. A 3.5kb c-fms exon 2 promoter (but not the 300bp proximal promoter) is also active in a wide diversity of tumor cell lines. The interesting exception is the melanoma cell line K1735, in which the promoter is completely shut down and expression of c-fms causes growth arrest and cell death. The activity of the exon 2 promoter in these nonmacrophages is at least as serum responsive as the classic serum-responsive promoter of the c-fos gene. It is further inducible in nonmacrophages by coexpression of the c-fms product. Unlike other CSF-1/c-fms-responsive promoters, the c-fms promoter is not responsive to activated Ras even when c-Ets-2 is coexpressed. In most lines, production of full length c-fms is prevented by a downstream intronic terminator, but in Lewis lung carcinoma, read-through does occur, and expression of both c-fms and other macrophage-specific genes such as lysozyme and urokinase becomes detectable in conditions of serum deprivation.
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Affiliation(s)
- D A Hume
- Centre for Molecular and Cellular Biology, University of Queensland, Brisbane, Australia
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44
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Abstract
Ternary complexes of DNA-dependent RNA polymerase with its DNA template and nascent transcript are central intermediates in transcription. In recent years, several unusual biochemical reactions have been discovered that affect the progression of RNA polymerase in ternary complexes through various transcription units. These reactions can be signaled intrinsically, by nucleic acid sequences and the RNA polymerase, or extrinsically, by protein or other regulatory factors. These factors can affect any of these processes, including promoter proximal and promoter distal pausing in both prokaryotes and eukaryotes, and therefore play a central role in regulation of gene expression. In eukaryotic systems, at least two of these factors appear to be related to cellular transformation and human cancers. New models for the structure of ternary complexes, and for the mechanism by which they move along DNA, provide plausible explanations for novel biochemical reactions that have been observed. These models predict that RNA polymerase moves along DNA without the constant possibility of dissociation and consequent termination. A further prediction of these models is that the polymerase can move in a discontinuous or inchworm-like manner. Many direct predictions of these models have been confirmed. However, one feature of RNA chain elongation not predicted by the model is that the DNA sequence can determine whether the enzyme moves discontinuously or monotonically. In at least two cases, the encounter between the RNA polymerase and a DNA block to elongation appears to specifically induce a discontinuous mode of synthesis. These findings provide important new insights into the RNA chain elongation process and offer the prospect of understanding many significant biological regulatory systems at the molecular level.
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Affiliation(s)
- S M Uptain
- Department of Molecular and Cell Biology, University of California at Berkeley 94720, USA.
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45
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Marshall NF, Peng J, Xie Z, Price DH. Control of RNA polymerase II elongation potential by a novel carboxyl-terminal domain kinase. J Biol Chem 1996; 271:27176-83. [PMID: 8900211 DOI: 10.1074/jbc.271.43.27176] [Citation(s) in RCA: 506] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
The entry of RNA polymerase II into a productive mode of elongation is controlled, in part, by the postinitiation activity of positive transcription elongation factor b (P-TEFb) (Marshall, N. F., and Price, D. H. (1995) J. Biol. Chem. 270, 12335-12338). We report here that removal of the carboxyl-terminal domain (CTD) of the large subunit of RNA polymerase II abolishes productive elongation. Correspondingly, we found that P-TEFb can phosphorylate the CTD of pure RNA polymerase II. Furthermore, P-TEFb can phosphorylate the CTD of RNA polymerase II when the polymerase is in an early elongation complex. Both the function and kinase activity of P-TEFb are blocked by the drugs 5, 6-dichloro-1-beta-D-ribofuranosylbenzimidazole (DRB) and H-8. P-TEFb is distinct from transcription factor IIH (TFIIH) because the two factors have no subunits in common, P-TEFb is more sensitive to DRB than is TFIIH, and most importantly, TFIIH cannot substitute functionally for P-TEFb. We propose that phosphorylation of the CTD by P-TEFb controls the transition from abortive into productive elongation mode.
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Affiliation(s)
- N F Marshall
- Department of Biochemistry, University of Iowa, Iowa City, Iowa 52242, USA
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Yue X, Ross IL, Browne CM, Lichanska A, Favot P, Ostrowski MC, Hume DA. Transcriptional control of the expression of the c-fms gene encoding the receptor for macrophage colony-stimulating factor (CSF-1). Immunobiology 1996; 195:461-76. [PMID: 8933151 DOI: 10.1016/s0171-2985(96)80016-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- X Yue
- Centre for Molecular and Cellular Biology, University of Queensland, Brisbane, Australia
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Iwakuma T, Shiraishi A, Fukuhara M, Kawate H, Sekiguchi M. Organization and expression of the mouse gene for DNA repair methyltransferase. DNA Cell Biol 1996; 15:863-72. [PMID: 8892758 DOI: 10.1089/dna.1996.15.863] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
06-Methylguanine-DNA methyltransferase (MGMT) is present in various organisms, from bacteria to human cells, and plays an important role in preventing mutations caused by alkylating substances. To understand better the regulatory mechanism involved in the expression of the gene and to construct a mouse model to investigate roles of the enzyme in carcinogenesis, the genomic sequence for mouse methyltransferase was isolated and characterized. The gene consists of 5 exons and spans over 180 kb, whereas mRNA for the enzyme was less than 1 kb. The promoter region for the gene is GC-rich, contains many Sp1 recognition sequences and lacks typical TATA and CCAAT boxes. Primer extension and S1 mapping revealed the existence of multiple transcription initiation sites, among which a major site was defined as +1. The putative promoter region was placed upstream of the chloramphenicol acetyltransferase (CAT) reporter gene and the construct was introduced into mouse NIH-3T3 cells. Deletion analyses revealed that a sequence from -262 to + 56 carries the basic promoter activity. In addition, an adjacent region, spanning from +56 to +95, carries an E2F-like element that greatly stimulates the frequency of transcription. Alteration of TTTTGGGGC to TTAACGGGC considerably reduced the activity.
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Affiliation(s)
- T Iwakuma
- Department of Biochemistry, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Japan
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Chen H, Lin B, Chen CL, Johnson PF, Chou JY. Role of the transcription factor C/EBP beta in expression of a rat pregnancy-specific glycoprotein gene. DNA Cell Biol 1995; 14:681-8. [PMID: 7646815 DOI: 10.1089/dna.1995.14.681] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Pregnancy-specific glycoproteins (PSGs), which are the major placental proteins, and the carcinoembryonic antigens comprise a subfamily within the immunoglobulin superfamily. To understand the molecular mechanisms underlying the control of PSG expression, we characterized the promoter elements of a rodent PSG gene, rnCGM3, and showed that DNA elements at nucleotides -326 to -185 (PI) relative to the translation start site of rnCGM3 function as a promoter. The rnCGM3 PI promoter contains two placental factor binding sites, PISI and PISII. Both are transcription activation elements. In the present report, we screened a placental expression cDNA library with a rnCGM3-PISII probe (nucleotides -263 to -233) encompassing two overlapping palindromes (TGTTGCTCAACATGTTG) and demonstrated that the PISII-binding factor is C/EBP beta, a leucine zipper family of transcription factor. Gel mobility-shift and transient expression analyses showed that C/EBP beta and C/EBP isoforms, C/EBP alpha and C/EBP delta, bind to the PISII element and trans-activate rnCGM3 gene expression. Deletion of PISII from the rnCGM3 PI promoter greatly reduced the basal as well as the C/EBP-activated rnCGM3 expression. Gel supershift assays demonstrated that C/EBP beta is the placental isoform that binds to the PISII site rnCGM3. Moreover, C/EBP beta is expressed in high levels in the placenta, ovary, liver, lung, heart, and spleen, in contrast to C/EBP alpha, which is expressed primarily in the liver and only low levels in the placenta. Our results demonstrate that C/EBP beta is one of the transcription factors that positively regulate rnCGM3 expression during pregnancy.
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Affiliation(s)
- H Chen
- Human Genetics Branch, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
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Marshall NF, Price DH. Purification of P-TEFb, a transcription factor required for the transition into productive elongation. J Biol Chem 1995; 270:12335-8. [PMID: 7759473 DOI: 10.1074/jbc.270.21.12335] [Citation(s) in RCA: 393] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Production of full-length runoff transcripts in vitro and functional mRNA in vivo is sensitive to the drug 5,6-dichloro-1-beta-D-ribofuranosylbenzimidazole (DRB). We previously proposed the existence of an activity, P-TEF (positive transcription elongation factor) that functions in a DRB-sensitive manner to allow RNA polymerase II elongation complexes to efficiently synthesize long transcripts (Marshall, N. F. and Price, D. H. (1992) Mol. Cell. Biol. 12, 2078-2090). We have fractionated nuclear extracts of Drosophila melanogaster Kc cells and identified three activities, P-TEFa, factor 2, and P-TEFb, that are directly involved in reconstructing DRB-sensitive transcription. P-TEFb is essential for the production of DRB-sensitive long transcripts in vitro, while P-TEFa and factor 2 are stimulatory. P-TEFb activity is associated with a protein comprising two polypeptide subunits with apparent molecular masses of 124 and 43 kDa. Using a P-TEFb-dependent transcription system, we show that P-TEFb acts after initiation and is the limiting factor in the production of long run-off transcripts.
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Affiliation(s)
- N F Marshall
- Department of Biochemistry, University of Iowa, Iowa City 52242, USA
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50
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Harrison L, Ascione AG, Wilson DM, Demple B. Characterization of the promoter region of the human apurinic endonuclease gene (APE). J Biol Chem 1995; 270:5556-64. [PMID: 7534297 DOI: 10.1074/jbc.270.10.5556] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Apurinic/apyrimidinic (AP) sites are mutagenic and block DNA synthesis in vitro. Repair of AP sites is initiated by AP endonucleases that cleave just 5' to the damage. We linked a 4.1-kilobase pair HindIII DNA fragment from the region upstream of the human AP endonuclease gene (APE) to the chloramphenicol acetyltransferase (CAT) gene. Deletions generated constructs containing 1.9 kilobase pairs to 50 base pairs (bp) of the APE upstream region. Transient transfection studies in HeLa cells established that the basal APE promoter is contained within a 500-bp fragment. The major transcriptional start site in HeLa, hepatoma (HepG2), and myeloid leukemic (K562) cells was mapped to a cluster of sites approximately 130 bp downstream of a putative "CCAAT box," approximately 130 bp 5' of the first splice junction in APE. Deletion of 5' sequences to within 10 bp of the CCAAT box reduced the CAT activity by only about half, and removal of the CCAAT box region left a residual promotor activity approximately 9%. Deletion to 31 bp upstream of the transcriptional start site abolished APE promoter activity. DNA sequence analysis revealed potential transcription factor recognition sites in the APE promoter. Gel mobility-shift assays showed that both human upstream factor and Sp1 can bind their respective sites in the APE promoter. However, DNase I footprinting using HeLa nuclear extract showed that the binding of Sp1 and upstream factor is blocked by the binding of other proteins to the nearby CCAAT box region.
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Affiliation(s)
- L Harrison
- Department of Molecular and Cellular Toxicology, Harvard School of Public Health, Boston, Massachusetts 02115
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