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Azevedo-Pouly A, Hale MA, Swift GH, Hoang CQ, Deering TG, Xue J, Wilkie TM, Murtaugh LC, MacDonald RJ. Key transcriptional effectors of the pancreatic acinar phenotype and oncogenic transformation. PLoS One 2023; 18:e0291512. [PMID: 37796967 PMCID: PMC10553828 DOI: 10.1371/journal.pone.0291512] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Accepted: 08/30/2023] [Indexed: 10/07/2023] Open
Abstract
Proper maintenance of mature cellular phenotypes is essential for stable physiology, suppression of disease states, and resistance to oncogenic transformation. We describe the transcriptional regulatory roles of four key DNA-binding transcription factors (Ptf1a, Nr5a2, Foxa2 and Gata4) that sit at the top of a regulatory hierarchy controlling all aspects of a highly differentiated cell-type-the mature pancreatic acinar cell (PAC). Selective inactivation of Ptf1a, Nr5a2, Foxa2 and Gata4 individually in mouse adult PACs rapidly altered the transcriptome and differentiation status of PACs. The changes most emphatically included transcription of the genes for the secretory digestive enzymes (which conscript more than 90% of acinar cell protein synthesis), a potent anabolic metabolism that provides the energy and materials for protein synthesis, suppressed and properly balanced cellular replication, and susceptibility to transformation by oncogenic KrasG12D. The simultaneous inactivation of Foxa2 and Gata4 caused a greater-than-additive disruption of gene expression and uncovered their collaboration to maintain Ptf1a expression and control PAC replication. A measure of PAC dedifferentiation ranked the effects of the conditional knockouts as Foxa2+Gata4 > Ptf1a > Nr5a2 > Foxa2 > Gata4. Whereas the loss of Ptf1a or Nr5a2 greatly accelerated Kras-mediated transformation of mature acinar cells in vivo, the absence of Foxa2, Gata4, or Foxa2+Gata4 together blocked transformation completely, despite extensive dedifferentiation. A lack of correlation between PAC dedifferentiation and sensitivity to oncogenic KrasG12D negates the simple proposition that the level of differentiation determines acinar cell resistance to transformation.
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Affiliation(s)
- Ana Azevedo-Pouly
- Department of Molecular Biology and the Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
| | - Michael A. Hale
- Department of Molecular Biology and the Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
| | - Galvin H. Swift
- Department of Molecular Biology and the Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
| | - Chinh Q. Hoang
- Department of Molecular Biology and the Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
| | - Tye G. Deering
- Department of Molecular Biology and the Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
| | - Jumin Xue
- Department of Molecular Biology and the Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
| | - Thomas M. Wilkie
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
| | - L. Charles Murtaugh
- Department of Human Genetics, University of Utah, Salt Lake City, Utah, United States of America
| | - Raymond J. MacDonald
- Department of Molecular Biology and the Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
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Armendariz DA, Sundarrajan A, Hon GC. Breaking enhancers to gain insights into developmental defects. eLife 2023; 12:e88187. [PMID: 37497775 PMCID: PMC10374278 DOI: 10.7554/elife.88187] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Accepted: 07/19/2023] [Indexed: 07/28/2023] Open
Abstract
Despite ground-breaking genetic studies that have identified thousands of risk variants for developmental diseases, how these variants lead to molecular and cellular phenotypes remains a gap in knowledge. Many of these variants are non-coding and occur at enhancers, which orchestrate key regulatory programs during development. The prevailing paradigm is that non-coding variants alter the activity of enhancers, impacting gene expression programs, and ultimately contributing to disease risk. A key obstacle to progress is the systematic functional characterization of non-coding variants at scale, especially since enhancer activity is highly specific to cell type and developmental stage. Here, we review the foundational studies of enhancers in developmental disease and current genomic approaches to functionally characterize developmental enhancers and their variants at scale. In the coming decade, we anticipate systematic enhancer perturbation studies to link non-coding variants to molecular mechanisms, changes in cell state, and disease phenotypes.
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Affiliation(s)
- Daniel A Armendariz
- Cecil H. and Ida Green Center for Reproductive Biology Sciences, University of Texas Southwestern Medical Center, Dallas, United States
| | - Anjana Sundarrajan
- Cecil H. and Ida Green Center for Reproductive Biology Sciences, University of Texas Southwestern Medical Center, Dallas, United States
| | - Gary C Hon
- Cecil H. and Ida Green Center for Reproductive Biology Sciences, University of Texas Southwestern Medical Center, Dallas, United States
- Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, United States
- Lyda Hill Department of Bioinformatics, Department of Obstetrics and Gynecology, University of Texas Southwestern Medical Center, Dallas, United States
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3
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Ni C, Buszczak M. The homeostatic regulation of ribosome biogenesis. Semin Cell Dev Biol 2023; 136:13-26. [PMID: 35440410 PMCID: PMC9569395 DOI: 10.1016/j.semcdb.2022.03.043] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 03/30/2022] [Accepted: 03/31/2022] [Indexed: 12/22/2022]
Abstract
The continued integrity of biological systems depends on a balance between interdependent elements at the molecular, cellular, and organismal levels. This is particularly true for the generation of ribosomes, which influence almost every aspect of cell and organismal biology. Ribosome biogenesis (RiBi) is an energetically demanding process that involves all three RNA polymerases, numerous RNA processing factors, chaperones, and the coordinated expression of 79-80 ribosomal proteins (r-proteins). Work over the last several decades has revealed that the dynamic regulation of ribosome production represents a major mechanism by which cells maintain homeostasis in response to changing environmental conditions and acute stress. More recent studies suggest that cells and tissues within multicellular organisms exhibit dramatically different levels of ribosome production and protein synthesis, marked by the differential expression of RiBi factors. Thus, distinct bottlenecks in the RiBi process, downstream of rRNA transcription, may exist within different cell populations of multicellular organisms during development and in adulthood. This review will focus on our current understanding of the mechanisms that link the complex molecular process of ribosome biogenesis with cellular and organismal physiology. We will discuss diverse topics including how different steps in the RiBi process are coordinated with one another, how MYC and mTOR impact RiBi, and how RiBi levels change between stem cells and their differentiated progeny. In turn, we will also review how regulated changes in ribosome production itself can feedback to influence cell fate and function.
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Affiliation(s)
- Chunyang Ni
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9148, USA
| | - Michael Buszczak
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9148, USA.
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4
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Use of Genome Editing Techniques to Produce Transgenic Farm Animals. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1354:279-297. [PMID: 34807447 PMCID: PMC9810480 DOI: 10.1007/978-3-030-85686-1_14] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Recombinant proteins are essential for the treatment and diagnosis of clinical human ailments. The availability and biological activity of recombinant proteins is heavily influenced by production platforms. Conventional production platforms such as yeast, bacteria, and mammalian cells have biological and economical challenges. Transgenic livestock species have been explored as an alternative production platform for recombinant proteins, predominantly through milk secretion; the strategy has been demonstrated to produce large quantities of biologically active proteins. The major limitation of utilizing livestock species as bioreactors has been efforts required to alter the genome of livestock. Advancements in the genome editing field have drastically improved the ability to genetically engineer livestock species. Specifically, genome editing tools such as the CRISPR/Cas9 system have lowered efforts required to generate genetically engineered livestock, thus minimizing restrictions on the type of genetic modification in livestock. In this review, we discuss characteristics of transgenic animal bioreactors and how the use of genome editing systems enhances design and availability of the animal models.
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Transcriptional Maintenance of Pancreatic Acinar Identity, Differentiation, and Homeostasis by PTF1A. Mol Cell Biol 2016; 36:3033-3047. [PMID: 27697859 DOI: 10.1128/mcb.00358-16] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Accepted: 09/23/2016] [Indexed: 12/17/2022] Open
Abstract
Maintenance of cell type identity is crucial for health, yet little is known of the regulation that sustains the long-term stability of differentiated phenotypes. To investigate the roles that key transcriptional regulators play in adult differentiated cells, we examined the effects of depletion of the developmental master regulator PTF1A on the specialized phenotype of the adult pancreatic acinar cell in vivo Transcriptome sequencing and chromatin immunoprecipitation sequencing results showed that PTF1A maintains the expression of genes for all cellular processes dedicated to the production of the secretory digestive enzymes, a highly attuned surveillance of unfolded proteins, and a heightened unfolded protein response (UPR). Control by PTF1A is direct on target genes and indirect through a ten-member transcription factor network. Depletion of PTF1A causes an imbalance that overwhelms the UPR, induces cellular injury, and provokes acinar metaplasia. Compromised cellular identity occurs by derepression of characteristic stomach genes, some of which are also associated with pancreatic ductal cells. The loss of acinar cell homeostasis, differentiation, and identity is directly relevant to the pathologies of pancreatitis and pancreatic adenocarcinoma.
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6
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Fokas E, O'Neill E, Gordon-Weeks A, Mukherjee S, McKenna WG, Muschel RJ. Pancreatic ductal adenocarcinoma: From genetics to biology to radiobiology to oncoimmunology and all the way back to the clinic. BIOCHIMICA ET BIOPHYSICA ACTA 2015; 1855:61-82. [PMID: 25489989 DOI: 10.1016/j.bbcan.2014.12.001] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2014] [Revised: 12/01/2014] [Accepted: 12/03/2014] [Indexed: 02/07/2023]
Abstract
Pancreatic ductal adenocarcinoma (PDAC) is the fourth leading cause of cancer death. Despite improvements in the clinical management, the prognosis of PDAC remains dismal. In the present comprehensive review, we will examine the knowledge of PDAC genetics and the new insights into human genome sequencing and clonal evolution. Additionally, the biology and the role of the stroma in tumour progression and response to treatment will be presented. Furthermore, we will describe the evidence on tumour chemoresistance and radioresistance and will provide an overview on the recent advances in PDAC metabolism and circulating tumour cells. Next, we will explore the characteristics and merits of the different mouse models of PDAC. The inflammatory milieu and the immunosuppressive microenvironment mediate tumour initiation and treatment failure. Hence, we will also review the inflammatory and immune escaping mechanisms and the new immunotherapies tested in PDAC. A better understanding of the different mechanisms of tumour formation and progression will help us to identify the best targets for testing in future clinical studies of PDAC.
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MESH Headings
- Animals
- Cancer Vaccines/therapeutic use
- Carcinoma, Pancreatic Ductal/genetics
- Carcinoma, Pancreatic Ductal/immunology
- Carcinoma, Pancreatic Ductal/therapy
- Cell Transformation, Neoplastic/genetics
- Cell Transformation, Neoplastic/pathology
- Disease Models, Animal
- Drug Resistance, Neoplasm/genetics
- Drug Resistance, Neoplasm/immunology
- Humans
- Immunotherapy/methods
- Inflammation/pathology
- Mice
- Neoplastic Cells, Circulating/immunology
- Neoplastic Cells, Circulating/pathology
- Pancreatic Neoplasms/genetics
- Pancreatic Neoplasms/immunology
- Pancreatic Neoplasms/therapy
- Radiation Tolerance/genetics
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Affiliation(s)
- Emmanouil Fokas
- Department of Oncology, Oxford Institute for Radiation Oncology, Oxford University, Oxford, UK.
| | - Eric O'Neill
- Department of Oncology, Oxford Institute for Radiation Oncology, Oxford University, Oxford, UK
| | - Alex Gordon-Weeks
- Nuffield Department of Surgical Sciences, University of Oxford, Oxford, UK
| | - Somnath Mukherjee
- Department of Oncology, Oxford Institute for Radiation Oncology, Oxford University, Oxford, UK
| | - W Gillies McKenna
- Department of Oncology, Oxford Institute for Radiation Oncology, Oxford University, Oxford, UK
| | - Ruth J Muschel
- Department of Oncology, Oxford Institute for Radiation Oncology, Oxford University, Oxford, UK
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7
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Smith HW, Muller WJ. Transgenic mouse models--a seminal breakthrough in oncogene research. Cold Spring Harb Protoc 2013; 2013:1099-1108. [PMID: 24298026 DOI: 10.1101/pdb.top069765] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Transgenic mouse models are an integral part of modern cancer research, providing a versatile and powerful means of studying tumor initiation and progression, metastasis, and therapy. The present repertoire of these models is very diverse, with a wide range of strategies used to induce tumorigenesis by expressing dominant-acting oncogenes or disrupting the function of tumor-suppressor genes, often in a highly tissue-specific manner. Much of the current technology used in the creation and characterization of transgenic mouse models of cancer will be discussed in depth elsewhere. However, to gain a complete appreciation and understanding of these complex models, it is important to review the history of the field. Transgenic mouse models of cancer evolved as a new and, compared with the early cell-culture-based techniques, more physiologically relevant approach for studying the properties and transforming capacities of oncogenes. Here, we will describe early transgenic mouse models of cancer based on tissue-specific expression of oncogenes and discuss their impact on the development of this still rapidly growing field.
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Affiliation(s)
- Harvey W Smith
- Department of Biochemistry and Goodman Cancer Research Center, McGill University, Montreal, Quebec H3A 1A3, Canada
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8
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Zhang Y, Chen L, Yang J, Fleming JB, Chiao PJ, Logsdon CD, Li M. Study human pancreatic cancer in mice: how close are they? Biochim Biophys Acta Rev Cancer 2012; 1835:110-8. [PMID: 23147198 DOI: 10.1016/j.bbcan.2012.11.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2012] [Revised: 10/31/2012] [Accepted: 11/01/2012] [Indexed: 12/15/2022]
Abstract
Pancreatic cancer is the fourth leading cause of cancer deaths and is characterized by dismal prognosis. Xenograft and genetically engineered mouse (GEM) models have recapitulated critical elements of human pancreatic cancer, providing useful tools to probe the underlying cause of cancer etiology. In this review, we provide a brief description of the common genetic lesions that occur during the development of pancreatic cancer. Next, we describe the strengths and weaknesses of these two models and highlight key discoveries each has made. Although the relative merits of GEM and xenograft pancreatic cancer mouse models are subject to debate, both systems have and will continue to yield essential insights in understanding pancreatic cancer etiology. This information is critical for the development of new methods to screen, treat, and prevent pancreatic cancer.
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Affiliation(s)
- Yuqing Zhang
- Department of Cancer Biology, the University of Texas MD Anderson Cancer Center, USA
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9
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Seleznik GM, Reding T, Romrig F, Saito Y, Mildner A, Segerer S, Sun LK, Regenass S, Lech M, Anders HJ, McHugh D, Kumagi T, Hiasa Y, Lackner C, Haybaeck J, Angst E, Perren A, Balmer ML, Slack E, MacPherson A, Manz MG, Weber A, Browning JL, Arkan MC, Rülicke T, Aguzzi A, Prinz M, Graf R, Heikenwalder M. Lymphotoxin β receptor signaling promotes development of autoimmune pancreatitis. Gastroenterology 2012; 143:1361-1374. [PMID: 22863765 DOI: 10.1053/j.gastro.2012.07.112] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/25/2012] [Revised: 07/09/2012] [Accepted: 07/28/2012] [Indexed: 12/24/2022]
Abstract
BACKGROUND & AIMS Little is known about the pathogenic mechanisms of autoimmune pancreatitis (AIP), an increasingly recognized, immune-mediated form of chronic pancreatitis. Current treatment options are limited and disease relapse is frequent. We investigated factors that contribute to the development of AIP and new therapeutic strategies. METHODS We used quantitative polymerase chain reaction, immunohistochemical, and enzyme-linked immunosorbent analyses to measure the expression of cytokines and chemokines in tissue and serum samples from patients with and without AIP. We created a mouse model of human AIP by overexpressing lymphotoxin (LT)α and β specifically in acinar cells (Ela1-LTab mice). RESULTS Messenger RNA levels of LTα and β were increased in pancreatic tissues from patients with AIP, compared with controls, and expression of chemokines (CXCL13, CCL19, CCL21, CCL1, and B-cell-activating factor) was increased in pancreatic and serum samples from patients. Up-regulation of these factors was not affected by corticosteroid treatment. Acinar-specific overexpression of LTαβ (Ela1-LTαβ) in mice led to an autoimmune disorder with various features of AIP. Chronic inflammation developed only in the pancreas but was sufficient to cause systemic autoimmunity. Acinar-specific overexpression of LTαβ did not cause autoimmunity in mice without lymphocytes (Ela1-LTab/Rag1(-/-)); moreover, lack of proinflammatory monocytes (Ela1-LTab/Ccr2(-/-)) failed to prevent AIP but prevented early pancreatic tissue damage. Administration of corticosteroids reduced pancreatitis but did not affect production of autoantibodies, such as antipancreatic secretory trypsin inhibitor in Ela1-LTab mice. In contrast, inhibition of LTβR signaling reduced chemokine expression, renal immune-complex deposition, and features of AIP in Ela1-LTab mice. CONCLUSIONS Overexpression of LTαβ specifically in acinar cells of mice causes features of AIP. Reagents that neutralize LTβR ligands might be used to treat patients with AIP.
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Affiliation(s)
| | - Theresia Reding
- Department of Surgery, Swiss Hepato-Pancreato-Biliary Center, University Hospital Zurich, Switzerland
| | - Franziska Romrig
- Second Department of Medicine, Klinikum Rechts der Isar, Technical University of Munich, Munich, Germany
| | - Yasuyuki Saito
- Division of Haematology, University Hospital Zurich, Switzerland
| | - Alexander Mildner
- Department of Neuropathology & BIOSS Centre for Biological Signaling Studies, University of Freiburg, Freiburg, Germany
| | - Stephan Segerer
- Division of Nephrology, University Hospital Zurich, Switzerland
| | - Li-Kang Sun
- Department of Surgery, Swiss Hepato-Pancreato-Biliary Center, University Hospital Zurich, Switzerland
| | - Stephan Regenass
- Division of Clinical Immunology, University Hospital Zurich, Switzerland
| | - Maciej Lech
- Medizinische Klinik IV, Klinikum der Universität München, Campus Innenstadt, Munich, Germany
| | - Hans-Joachim Anders
- Medizinische Klinik IV, Klinikum der Universität München, Campus Innenstadt, Munich, Germany
| | - Donal McHugh
- Institute of Neuropathology, Zurich, Switzerland
| | - Teru Kumagi
- Gastroenterology and Metabology, Ehime University, Graduate School of Medicine, Shitsukawa To-on, Ehime, Japan
| | - Yoichi Hiasa
- Gastroenterology and Metabology, Ehime University, Graduate School of Medicine, Shitsukawa To-on, Ehime, Japan
| | - Carolin Lackner
- Institute of Pathology, Medical University Graz, Graz, Austria
| | | | - Eliane Angst
- Departments of Visceral Surgery and Pathology, Inselspital, University of Bern, Switzerland
| | - Aurel Perren
- Departments of Visceral Surgery and Pathology, Inselspital, University of Bern, Switzerland
| | - Maria Luisa Balmer
- Department of Gastroenterology, Inselspital, University of Bern, Switzerland
| | - Emma Slack
- Department of Gastroenterology, Inselspital, University of Bern, Switzerland
| | - Andrew MacPherson
- Department of Gastroenterology, Inselspital, University of Bern, Switzerland
| | - Markus G Manz
- Division of Haematology, University Hospital Zurich, Switzerland
| | - Achim Weber
- Institute of Clinical Pathology, Zurich, Switzerland
| | | | - Melek Canan Arkan
- Second Department of Medicine, Klinikum Rechts der Isar, Technical University of Munich, Munich, Germany
| | - Thomas Rülicke
- Institute of Laboratory Animal Science, University of Veterinary Medicine Vienna, Vienna, Austria
| | | | - Marco Prinz
- Department of Neuropathology & BIOSS Centre for Biological Signaling Studies, University of Freiburg, Freiburg, Germany
| | - Rolf Graf
- Department of Surgery, Swiss Hepato-Pancreato-Biliary Center, University Hospital Zurich, Switzerland
| | - Mathias Heikenwalder
- Institute of Neuropathology, Zurich, Switzerland; Institute of Virology, Technische Universität München/Helmholtz-Zentrum München, München Germany.
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10
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Abstract
Notch-dependent CSL transcription complexes control essential biological processes such as cell proliferation, differentiation, and cell-fate decisions in diverse developmental systems. The orthologous proteins CBF1/Rbpj (mammalian), Su(H) (Drosophila), and Lag-1 (Caenorhabditis elegans) compose the CSL family of sequence-specific DNA-binding transcription factors. The CSL proteins are best known for their role in canonical Notch signaling. However, CSL factors also form transcription complexes that can function independent of Notch signaling and include repression and activation of target gene transcription. Because the different complexes share CSL as a DNA-binding subunit, they can control overlapping sets of genes; but they can also control distinct sets when partnered with tissue-specific cofactors that restrict DNA-sequence recognition or stability of the DNA-bound complex. The Notch-independent functions of CSL and the processes they regulate will be reviewed here with a particular emphasis on the tissue-specific CSL-activator complex with the bHLH factor Ptf1a.
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Affiliation(s)
- Jane E Johnson
- Department of Neuroscience, UT Southwestern Medical Center, Dallas, Texas, USA
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11
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Scheele GA, Kern HF. Selective Regulation of Gene Expression in the Exocrine Pancreas. Compr Physiol 2011. [DOI: 10.1002/cphy.cp060325] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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12
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Schütte U, Bisht S, Brossart P, Feldmann G. Recent developments of transgenic and xenograft mouse models of pancreatic cancer for translational research. Expert Opin Drug Discov 2010; 6:33-48. [DOI: 10.1517/17460441.2011.534453] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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13
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Abstract
ABSTRACTDevelopments, both recent and potential, in procedures for manipulating embryos are described. The procedures considered include: embryo transfer, multiple ovulation and embryo recovery, recovery of oocytes, in vitro maturation (IVM) and fertilization (IVF) of oocytes, in vitro culture of zygotes, embryo splitting and nuclear transfer, embryo storage, embryo sexing, gene transfer and embryo stem cells. The impact of these procedures on breeding strategies such as multiple ovulation and embryo transfer (MOET) nucleus breeding schemes and progeny testing are discussed for both dairy and beef cattle.For MOET nucleus schemes all these procedures have potential applications in producing maximal rates of genetic progress for a fixed rate of inbreeding. With the current effectiveness of the procedures, embryo sexing and nuclear transfer would have the most impact. The potential for increasing genetic progress through progeny testing is enhanced using multiple ovulation, embryo recovery and transfer in cows to breed bulls, but no other procedures appeared to offer major benefits. The efficiency of beef production from the dairy herd could be increased either by using IVM and IVF to produce more beef-type calves or, potentially, by cloning and embryo transfer, to produce pure beef calves. Procedures leading to the production of clone families would make an impact on the evaluation of genotypes and environments. Gene transfer may be used to modify the composition of milk including the production of pharmaceutical proteins, and to increase milk yield or the efficiency of lean meat production.It is concluded that, although much further research is required, the procedures discussed will have major implications for the structure and organization of dairy and beef cattle herds over the next decade.
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14
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Relationship of strain-dependent susceptibility to experimentally induced acute pancreatitis with regulation of Prss1 and Spink3 expression. J Transl Med 2010; 90:654-64. [PMID: 20157294 DOI: 10.1038/labinvest.2010.44] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
To analyze susceptibility to acute pancreatitis, five mouse strains including Japanese Fancy Mouse 1 (JF1), C57BL/6J, BALB/c, CBA/J, and C3H/HeJ were treated with either a cholecystokinin analog, cerulein, or a choline-deficient, ethionine-supplemented (CDE) diet. The severity of acute pancreatitis induced by cerulein was highest in C3H/HeJ and CBA/J, moderate in BALB/c, and mildest in C57BL/6J and JF1. Basal protein expression levels of the serine protease inhibitor, Kazal type 3 (Spink3) were higher in JF1 and C57BL/6J mice than those of the other three strains under normal feeding conditions. After treatment with cerulein, expression level of Spink3 increased remarkably in JF1 and mildly in C57BL/6J, BALB/c, CBA/J, and C3H/HeJ strains. Increased proteinase, serine, 1 (Prss1) protein expression accompanied by increased trypsin activity with cerulein treatment was observed in susceptible strains such as CBA/J and C3H/HeJ. Similar results were obtained with a CDE diet. In the 3 kb Spink3 promoter region, 92 or 8 nucleotide changes were found in JF1 or C3H vs C57BL/6J, respectively, whereas in the Prss1 promoter region 39 or 46 nucleotide changes were found in JF1 or C3H vs C57BL/6J, respectively. These results suggest that regulation of Prss1 and Spink3 expression is involved in the susceptibility to experimentally induced pancreatitis. The JF1 strain, which is derived from the Japanese wild mouse, will be useful to examine new mechanisms that may not be found in other laboratory mouse strains.
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15
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Abstract
LINE1 (L1) retrotransposons are genetic elements that are present in all mammalian genomes. L1s are active in both humans and mice, and are capable of copying themselves and inserting the copy into a new genomic location. These de novo insertions occasionally result in disease. Endogenous L1 retrotransposons can be modified to increase their activity and mutagenic power in a variety of ways. Here we outline the advantages of using modified L1 retrotransposons for performing random mutagenesis in rodents and discuss several potential applications.
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Affiliation(s)
- Eric M Ostertag
- University of Pennsylvania School of Medicine, Department of Genetics, Curie Blvd, Philadelphia, Pennsylvania 19104, USA.
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16
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Iida K, Li Y, McGrath BC, Frank A, Cavener DR. PERK eIF2 alpha kinase is required to regulate the viability of the exocrine pancreas in mice. BMC Cell Biol 2007; 8:38. [PMID: 17727724 PMCID: PMC2072952 DOI: 10.1186/1471-2121-8-38] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2007] [Accepted: 08/29/2007] [Indexed: 12/21/2022] Open
Abstract
Background Deficiency of the PERK eIF2α kinase in humans and mice results in postnatal exocrine pancreatic atrophy as well as severe growth and metabolic anomalies in other organs and tissues. To determine if the exocrine pancreatic atrophy is due to a cell-autonomous defect, the Perk gene was specifically ablated in acinar cells of the exocrine pancreas in mice. Results We show that expression of PERK in the acinar cells is required to maintain their viability but is not required for normal protein synthesis and secretion. Exocrine pancreatic atrophy in PERK-deficient mice was previously attributed to uncontrolled ER-stress followed by apoptotic cell death based on studies in cultured fibroblasts. However, we have found no evidence for perturbations in the endoplasmic reticulum or ER-stress and show that acinar cells succumb to a non-apoptotic form of cell death, oncosis, which is associated with a pronounced inflammatory response and induction of the pancreatitis stress response genes. We also show that mice carrying a knockout mutation of PERK's downstream target, ATF4, exhibit pancreatic deficiency caused by developmental defects and that mice ablated for ATF4's transcriptional target CHOP have a normal exocrine pancreas. Conclusion We conclude that PERK modulates secretory capacity of the exocrine pancreas by regulating cell viability of acinar cells.
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Affiliation(s)
- Kaori Iida
- Department of History of Science and Technology, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Yulin Li
- Department of Biology, Penn State University, University Park, PA 16802, USA
| | - Barbara C McGrath
- Department of Biology, Penn State University, University Park, PA 16802, USA
| | - Ami Frank
- Bacterial Diseases of Livestock, Agricultural Research Service, United States Department of Agriculture, Ames, IA 50010, USA
| | - Douglas R Cavener
- Department of Biology, Penn State University, University Park, PA 16802, USA
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17
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Beres TM, Masui T, Swift GH, Shi L, Henke RM, MacDonald RJ. PTF1 is an organ-specific and Notch-independent basic helix-loop-helix complex containing the mammalian Suppressor of Hairless (RBP-J) or its paralogue, RBP-L. Mol Cell Biol 2006; 26:117-30. [PMID: 16354684 PMCID: PMC1317634 DOI: 10.1128/mcb.26.1.117-130.2006] [Citation(s) in RCA: 177] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
PTF1 is a trimeric transcription factor essential to the development of the pancreas and to the maintenance of the differentiated state of the adult exocrine pancreas. It comprises a dimer of P48/PTF1a (a pancreas and neural restricted basic helix-loop-helix [bHLH] protein) and a class A bHLH protein, together with a third protein that we show can be either the mammalian Suppressor of Hairless (RBP-J) or its paralogue, RBP-L. In mature acinar cells, PTF1 exclusively contains the RBP-L isoform and is bound to the promoters of acinar specific genes. P48 interacts with the RBP subunit primarily through two short conserved tryptophan-containing motifs, similar to the motif of the Notch intracellular domain (NotchIC) that interacts with RBP-J. The transcriptional activities of the J and L forms of PTF1 are independent of Notch signaling, because P48 occupies the NotchIC docking site on RBP-J and RBP-L does not bind the NotchIC. Mutations that delete one or both of the RBP-interacting motifs of P48 eliminate RBP-binding and are associated with a human genetic disorder characterized by pancreatic and cerebellar agenesis, which indicates that the association of P48 and RBPs is required for proper embryonic development. The presence of related peptide motifs in other transcription factors indicates a broader Notch-independent function for RBPJ/SU(H).
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Affiliation(s)
- Thomas M Beres
- Department of Molecular Biology, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX 75390-9148, USA
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18
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Kong YM, Macdonald RJ, Wen X, Yang P, Barbera VM, Swift GH. A comprehensive survey of DNA-binding transcription factor gene expression in human fetal and adult organs. Gene Expr Patterns 2006; 6:678-86. [PMID: 16487753 DOI: 10.1016/j.modgep.2006.01.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2005] [Accepted: 01/05/2006] [Indexed: 01/18/2023]
Abstract
A global survey of RNA from 14 fetal and 12 adult human organs by RT-PCR determined the expression patterns of 790 genes encoding DNA-binding transcription factors. The data can be sorted to identify sets of transcription factors with expression relatively restricted to a given organ or to particular organ groups. These data are a resource to help define the spectrum of transcription factor control, contribute to the elucidation of transcription factor cascades responsible for the development and maintenance of each organ, and provide a baseline to study the effects of disease or developmental defects.
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Affiliation(s)
- Y Megan Kong
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, 75390, USA
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19
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Abstract
We summarize the current standard methods for overexpressing, inactivating, or manipulating genes, with special focus on nutritional and obesity research. These molecular biology procedures can be carried out with the maintenance of the genetic information to subsequent generations (transgenic technology) or devised to exclusively transfer the genetic material to a given target animal, which cannot be transmitted to the future progeny (gene therapy). On the other hand, the RNA interference (RNAi) approach allows for the creation of new experimental models by transient ablation of gene expression by degrading specific mRNA, which can be applied to assess different biological functions and mechanisms. The combination of these technologies contributes to the study of the function and regulation of different metabolism- and obesity-related genes as well as the identification of new pharmacologic targets for nutritional and therapeutic approaches.
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Affiliation(s)
- Javier Campión
- Department of Physiology and Nutrition, University of Navarra, Pamplona, Spain
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20
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Abstract
Pancreatic cancer remains one of the most lethal of all human malignancies. Until recently, preclinical studies have been hampered by the absence of mouse models faithfully recapitulating critical elements of the human disease. However, recent months have witnessed a flurry of activity with respect to prospective mouse models. This progress now allows the evaluation of novel strategies for early detection, chemoprevention, and therapy and also provides new insights regarding the potential for differentiated and undifferentiated cell types to act as cells of origin for pancreatic ductal adenocarcinoma.
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Affiliation(s)
- Steven D Leach
- The Sidney Kimmel Cancer Center at Johns Hopkins, 600 North Wolfe Street/Osler 603, Baltimore, MD 21287, USA.
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21
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Abstract
The hen has long held promise as a low cost, high-yield bioreactor for the production of human biopharmaceuticals in egg whites. A typical egg white contains 3.5-4.0 grams of protein, more than half of which comes from a single gene (ovalbumin). Harnessing the power of the gene to express a recombinant protein could yield up to a gram or more of the protein in the naturally sterile egg. Accordingly, a major effort has been underway for more than a decade to develop robust methods for modification of the chicken genome. This effort intensified in the mid-1990s when several avian transgenic companies entered the scene. Progress has been made in that time but much remains to be done.
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Affiliation(s)
- Robert Ivarie
- Department of Genetics, University of Georgia, Athens, GA, 30602-7223, USA.
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22
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Ji B, Bi Y, Simeone D, Mortensen RM, Logsdon CD. Human pancreatic acinar cells do not respond to cholecystokinin. PHARMACOLOGY & TOXICOLOGY 2002; 91:327-32. [PMID: 12688376 DOI: 10.1034/j.1600-0773.2002.910610.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Pancreatic secretion can be influenced by cholecystokinin (CCK) either directly via actions on acinar cells or indirectly via actions on nerves. The presence and functional roles of CCK receptors on human pancreatic acinar cells remains unclear. In the current study human pancreatic acini were isolated and then treated with CCK-8, gastrin and/or carbachol. Functional parameters were measured including intracellular [Ca2+] and amylase secretion. It was observed that human acini did not respond to CCK agonists but did respond to carbachol with robust increases in functional parameters. Adenoviral-mediated gene transfer of CCK1 or CCK2 receptors to the human cells resulted in cell responses to CCK agonists. In order to determine the reason for the lack of responsiveness of the human acini, expression of receptor mRNAs was determined using quantitative RT-PCR and localized by in situ hybridization. mRNA levels for CCK1 receptors were approximately 30 times lower than those of CCK2 receptors, which were approximately 10 times lower than those of m3 Ach receptors as measured by quantitative PCR. Neither CCK1 nor CCK2 receptors were localized in adult human pancreas by in situ hybridization. These results indicate that human pancreatic acinar cells do not respond directly to CCK receptor activation and this is likely due to an insufficient level of receptor expression.
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Affiliation(s)
- Baoan Ji
- Department of Physiology, University of Michigan, Ann Arbor, MI 48109-0622, USA
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23
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Holland AM, Hale MA, Kagami H, Hammer RE, MacDonald RJ. Experimental control of pancreatic development and maintenance. Proc Natl Acad Sci U S A 2002; 99:12236-41. [PMID: 12221286 PMCID: PMC129428 DOI: 10.1073/pnas.192255099] [Citation(s) in RCA: 169] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
To investigate the role of the HOX-like homeoprotein PDX1 in the formation and maintenance of the pancreas, we have genetically engineered mice so that the only source of PDX1 is a transgene that can be controlled by the application of tetracycline or its analogue doxycycline. In these mice the coding region for the tetracycline-regulated transactivator (tTA(off)) has replaced the coding region of the endogenous Pdx1 gene to ensure correct temporal and spatial expression of the regulatable transactivator. In the absence of doxycycline, tTA(off) activates the transcription of a bicistronic transgene encoding PDX1 and an enhanced green fluorescent protein reporter, which acts as a visual marker of transgene expression in living cells. Expression of the transgene-encoded PDX1 rescues the Pdx1-null phenotype; the pancreata of these mice develop and function normally. The rescue is conditional; doxycycline-mediated repression of the transgenic Pdx1 throughout gestation recapitulates the Pdx1 null phenotype. Moreover, application of doxycycline at mid-pancreogenesis blocks further development. Adult animals of the rescue genotype that were treated with doxycycline for 3 weeks shut off Pdx1 expression, decreased insulin production, and lost the ability to maintain glucose homeostasis. These results demonstrate the feasibility of controlling the formation of an organ during embryogenesis in utero and the maintenance of the mature organ through the experimental manipulation of a key developmental regulator.
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Affiliation(s)
- Andrew M Holland
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
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24
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Grippo PJ, Nowlin PS, Cassaday RD, Sandgren EP. Cell-specific transgene expression from a widely transcribed promoter using Cre/lox in mice. Genesis 2002; 32:277-86. [PMID: 11948915 DOI: 10.1002/gene.10080] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Mice carrying two or more transgenes are used frequently to evaluate oncogene interactions during carcinogenesis. However, neoplastic transformation typically results in reduced expression both of differentiation-specific genes and of transgenes that use their promoters. In contrast, the more widely expressed metallothionein (MT) gene remains expressed at a high level in certain neoplasms, including those developing in pancreas. We have developed a system to maintain high-level, tissue-specific transgene expression during pancreatic carcinogenesis that uses Cre recombinase and a lox site-containing target transgene. Cre was expressed in pancreatic acinar cells under control of the elastase promoter (EL). Cre-mediated target transgene recombination placed a previously silent open-reading frame, encoding rat transforming growth factor alpha (TGFalpha), under control of the MT gene promoter. As long as DNA rearrangement does not occur in other cell types that express MT, TGFalpha expression will be restricted to acinar cells. Development of an effective target transgenic mouse required evaluation of multiple lineages to identify one with sufficient TGFalpha expression to induce pancreatic lesions after transgene rearrangement.
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Affiliation(s)
- Paul J Grippo
- Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, 2015 Linden Drive, Madison, WI 53226, USA
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25
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Ji B, Bi Y, Simeone D, Mortensen RM, Logsdon CD. Human pancreatic acinar cells lack functional responses to cholecystokinin and gastrin. Gastroenterology 2001; 121:1380-90. [PMID: 11729117 DOI: 10.1053/gast.2001.29557] [Citation(s) in RCA: 114] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
BACKGROUND & AIMS Pancreatic acinar cells from various species express cholecystokinin (CCK) A, CCK-B, or a combination of these CCK receptor subtypes. The presence and functional roles of CCK receptors on human acinar cells remain unclear. METHODS Acini isolated from human pancreas were treated with CCK receptor agonists, CCK-8 and gastrin, and an agonist for m3 muscarinic acetylcholine receptors (m3 AchR), carbachol. Functional parameters measured included intracellular [Ca(2+)], amylase secretion, and ERK phosphorylation. Binding studies were performed using (125)I-CCK-8. Expression of messenger RNAs (mRNAs) was determined using real-time quantitative reverse-transcription polymerase chain reaction (RT-PCR) and localized by in situ hybridization. RESULTS Human acini did not respond to CCK agonists. In contrast, they responded to carbachol with robust increases in each of the functional parameters. Moreover, the cells responded to CCK agonists after adenoviral-mediated gene transfer of CCK-A or CCK-B receptors. A low level of specific and a high level of nonspecific binding of (125)I-CCK-8 were observed. Quantitative RT-PCR indicated that the message levels for CCK-A receptors were approximately 30-fold lower than those of CCK-B receptors, which were approximately 10-fold lower than those of m3 Ach receptors. In situ hybridization indicated the presence of m3 Ach receptor and insulin mRNA but not CCK-A or CCK-B receptor mRNAs in adult human pancreas. CONCLUSIONS These data indicate that human pancreatic acinar cells do not respond to CCK receptor agonists in terms of expected functional parameters and show that this is due to an insufficient level of receptor expression.
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Affiliation(s)
- B Ji
- Department of Physiology, University of Michigan, 7710 Medical Sciences Building II, Ann Arbor, MI 48109-0622, USA
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26
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Rose SD, Swift GH, Peyton MJ, Hammer RE, MacDonald RJ. The role of PTF1-P48 in pancreatic acinar gene expression. J Biol Chem 2001; 276:44018-26. [PMID: 11562365 DOI: 10.1074/jbc.m106264200] [Citation(s) in RCA: 90] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The 100-base pair ELA1 transcriptional enhancer drives high level transcription to pancreatic acinar cells of transgenic mice and in transfected pancreatic acinar cells in culture. The A element within the enhancer is the sole positively acting element for acinar specificity. We show that the acinar cell-specific bHLH protein PTF1-P48 and the common bHLH cofactor HEB are part of the PTF1 complex that binds the A element and mediates its activity. Acinar-like activity of the enhancer can be reconstituted in HeLa cells by the introduction of P48, HEB, and the PDX1-containing trimeric homeodomain complex that binds the second pancreatic element of the enhancer. The 5' region of the mouse Ptf1-p48 gene from -12.5 to +0.2 kilobase pairs contains the regulatory information to direct expression in transgenic mice to the pancreas and other organs of the gut that express the endogenous Ptf1-p48 gene. The 5'-flanking sequence contains two activating regions, one of which is specific for acinar cells, and a repressing domain active in non-pancreatic cells. Comparison of the 5'-gene flanking regions of the mouse, rat, and human genes identified conserved sequence blocks containing binding sites for known gut transcription factors within the acinar cell-specific control region.
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Affiliation(s)
- S D Rose
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9148, USA
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27
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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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28
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Abstract
Antisense transgenesis provides a methodology for ablating gene expression in targeted tissues through the use of tissue-specific or controllable promoters. The two major features to be considered in the design of a construct for injection are (1) the target sequence and (2) the promoter to be used. Information is provided to help the investigator make decisions in these regards. The standard methodology of making transgenics is not replicated but some hints as how best to use a transgenic facility are provided. An overview of methods for studying transgene expression and target gene suppression is given. In summary, antisense transgenesis may provide a more readily achievable method for tissue-specific ablation of a gene's function than controllable knockouts provide.
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Affiliation(s)
- R P Erickson
- Steele Memorial Children's Research Center, University of Arizona College of Medicine, Tucson, Arizona 85724, USA
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29
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Lubon H. Transgenic animal bioreactors in biotechnology and production of blood proteins. BIOTECHNOLOGY ANNUAL REVIEW 1999; 4:1-54. [PMID: 9890137 DOI: 10.1016/s1387-2656(08)70066-8] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The regulatory elements of genes used to target the tissue-specific expression of heterologous human proteins have been studied in vitro and in transgenic mice. Hybrid genes exhibiting the desired performance have been introduced into large animals. Complex proteins like protein C, factor IX, factor VIII, fibrinogen and hemoglobin, in addition to simpler proteins like alpha 1-antitrypsin, antithrombin III, albumin and tissue plasminogen activator have been produced in transgenic livestock. The amount of functional protein secreted when the transgene is expressed at high levels may be limited by the required posttranslational modifications in host tissues. This can be overcome by engineering the transgenic bioreactor to express the appropriate modifying enzymes. Genetically engineered livestock are thus rapidly becoming a choice for the production of recombinant human blood proteins.
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Affiliation(s)
- H Lubon
- Plasma Derivatives Department, American Red Cross, Rockville, Maryland, USA.
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30
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Swift GH, Liu Y, Rose SD, Bischof LJ, Steelman S, Buchberg AM, Wright CV, MacDonald RJ. An endocrine-exocrine switch in the activity of the pancreatic homeodomain protein PDX1 through formation of a trimeric complex with PBX1b and MRG1 (MEIS2). Mol Cell Biol 1998; 18:5109-20. [PMID: 9710595 PMCID: PMC109096 DOI: 10.1128/mcb.18.9.5109] [Citation(s) in RCA: 138] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/1998] [Accepted: 06/01/1998] [Indexed: 11/20/2022] Open
Abstract
HOX proteins and some orphan homeodomain proteins form complexes with either PBX or MEIS subclasses of homeodomain proteins. This interaction can increase the binding specificity and transcriptional effectiveness of the HOX partner. Here we show that specific members of both PBX and MEIS subclasses form a multimeric complex with the pancreatic homeodomain protein PDX1 and switch the nature of its transcriptional activity. The two activities of PDX1 are exhibited through the 10-bp B element of the transcriptional enhancer of the pancreatic elastase I gene (ELA1). In pancreatic acinar cells the activity of the B element requires other elements of the ELA1 enhancer; in beta-cells the B element can activate a promoter in the absence of other enhancer elements. In acinar cell lines the activity is mediated by a complex comprising PDX1, PBX1b, and MRG1 (MEIS2). In contrast, beta-cell lines are devoid of PBX1b and MRG1, so that a trimeric complex does not form, and the beta-cell-type activity is mediated by PDX1 without PBX1b and MRG1. The presence of specific nuclear isoforms of PBX and MEIS is precisely regulated in a cell-type-specific manner. The beta-cell-type activity can be detected in acinar cells if the B element is altered to retain binding of PDX1 but prevent binding of the PDX1-PBX1b-MRG1 complex. These observations suggest that association with PBX and MEIS partners controls the nature of the transcriptional activity of the organ-specific PDX1 transcription factor in exocrine versus endocrine cells.
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Affiliation(s)
- G H Swift
- Department of Molecular Biology and Oncology, University of Texas Southwestern Medical Center, Dallas, Texas 75235, USA.
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31
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Bobek LA, Li H, Rojstaczer N, Jones C, Gross KW, Levine MJ. Tissue-specific expression of human salivary mucin gene, MUC7, in transgenic mice. Transgenic Res 1998; 7:195-204. [PMID: 10461391 DOI: 10.1023/a:1008841013622] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The MUC7 gene encodes the protein core of the low molecular weight human salivary mucin (MG2, mucin glycoprotein 2) and is expressed in a tissue-specific manner in salivary glands. The purpose of this study was to examine MUC7 expression by transgenic mouse technology. A 16 kb DNA fragment, containing the MUC7 gene (10 kb) and 3 kb of the upstream and 3 kb of the downstream sequences, was used to generate transgenic mice. We have identified five transgenic founder mice which were propagated as individual transgenic lines and analysed. Tissues of transgenic offspring from each line were analysed by RT-PCR to determine the sites of the MUC7 expression. The results indicated that only line 3 and line 5 expressed the MUC7 gene in salivary glands. The level of MUC7 expression in selected tissues was then determined by northern blot analyses. The results showed that line 3 mice contained high levels of MUC7 transcripts in the sublingual glands of both males and females and indicated low levels of MUC7 transcripts in the submandibular glands of females. No MUC7 expression was detected in this line by northern blot analysis in any other tissue tested. On the other hand, no expression of MUC7 was detected in any tissues of line 5 mice examined by northern blot analysis. A Southern blot analysis of human and mouse genomic DNA demonstrated multiple copies of the MUC7 transgene in line 3 and a single copy in line 5. Collectively, these results indicate that the regulatory sequences required for the tissue-specific expression of MUC7 are within the MUC7 transgene. However, the sequences necessary for expression comparable to that of MUC7 in human salivary glands may be missing from this construct. Western blot analysis of protein extracts from different tissues of transgenic mice line 3 showed that MUC7 gene product was produced in the submandibular-sublingual gland complex of both male and female mice and not in the other tissues examined.
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Affiliation(s)
- L A Bobek
- Department of Oral Biology, State University of New York at Buffalo 14214, USA
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32
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Holtmaat AJ, Oestreicher AB, Gispen WH, Verhaagen J. Manipulation of gene expression in the mammalian nervous system: application in the study of neurite outgrowth and neuroregeneration-related proteins. BRAIN RESEARCH. BRAIN RESEARCH REVIEWS 1998; 26:43-71. [PMID: 9600624 DOI: 10.1016/s0165-0173(97)00044-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
A fundamental issue in neurobiology entails the study of the formation of neuronal connections and their potential to regenerate following injury. In recent years, an expanding number of gene families has been identified involved in different aspects of neurite outgrowth and regeneration. These include neurotrophic factors, cell-adhesion molecules, growth-associated proteins, cytoskeletal proteins and chemorepulsive proteins. Genetic manipulation technology (transgenic mice, knockout mice, viral vectors and antisense oligonucleotides) has been instrumental in defining the function of these neurite outgrowth-related proteins. The aim of this paper is to provide an overview of the above-mentioned four approaches to manipulate gene expression in vivo and to discuss the progress that has been made using this technology in helping to understand the molecular mechanisms that regulate neurite outgrowth. We will show that work with transgenic mice and knockout mice has contributed significantly to the dissection of the function of several proteins with a key role in neurite outgrowth and neuronal survival. Recently developed viral vectors for gene transfer in postmitotic neurons have opened up new avenues to analyze the function of a protein following local expression in naive adult rodents. The initial results with viral vector-based gene transfer provide a conceptual framework for further studies on genetic therapy of neuroregeneration and neurodegenerative diseases.
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Affiliation(s)
- A J Holtmaat
- Graduate School of Neurosciences Amsterdam, Netherlands Institute for Brain Research
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33
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Hauge JG. From molecular genetics to diagnosis and gene therapy. ADVANCES IN VETERINARY MEDICINE 1997; 40:1-49. [PMID: 9395728 DOI: 10.1016/s0065-3519(97)80003-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- J G Hauge
- Department of Biochemistry, Physiology, and Nutrition, Norwegian College of Veterinary Medicine, Oslo, Norway
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34
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Tevethia MJ, Bonneau RH, Griffith JW, Mylin L. A simian virus 40 large T-antigen segment containing amino acids 1 to 127 and expressed under the control of the rat elastase-1 promoter produces pancreatic acinar carcinomas in transgenic mice. J Virol 1997; 71:8157-66. [PMID: 9343166 PMCID: PMC192272 DOI: 10.1128/jvi.71.11.8157-8166.1997] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The simian virus 40 large T antigen induces tumors in a wide variety of tissues in transgenic mice, the precise tissues depending on the tissue specificity of the upstream region controlling T-antigen expression. Expression of mutant T antigens that contain a subset of the protein's activities restricts the spectrum of tumors induced. Others showed previously that expression of a mutant large T antigen containing the N-terminal 121 amino acids (T1-121) under control of the lymphotropic papovavirus promoter resulted in slow-growing choroid plexus tumors, whereas full-length T antigen under the same promoter induced rapidly growing CPR tumors, T-cell lymphomas, and B-cell lymphomas. In those instances, the alteration in tumor induction or progression correlated with inability of the mutant large T antigen to bind the tumor suppressor p53. In the study reported here, we investigated the capacity of an N-terminal T antigen segment (T1-127) expressed in conjunction with small t antigen under control of the rat elastase-1 (E1) promoter to induce pancreatic tumors. The results show that pancreases of transgenic mice expressing T1-127 and small t antigen display acinar cell dysplasia at birth that progresses to neoplasia. The average age to death in these mice is within the range reported for transgenic mice expressing full-length T antigen under control of the E1 promoter. These results indicate that sequestering p53 by binding is not required for the development of rapidly growing acinar cell carcinomas. In addition, we provide evidence that small t antigen is unlikely to be required. Finally, we show that the p53 protein in acinar cell carcinomas is wild type in conformation.
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Affiliation(s)
- M J Tevethia
- Department of Microbiology and Immunology, Pennsylvania State University College of Medicine, Hershey 17033, USA
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35
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Wojnowski L, Zimmer A. Use of transgenic mice to study activation of retinoic acid-responsive promoters. Methods Enzymol 1997; 282:77-85. [PMID: 9330278 DOI: 10.1016/s0076-6879(97)82097-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- L Wojnowski
- Section on Genetics, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland 20892, USA
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Gestin M, Le Huërou-Luron I, Wicker-Planquart C, Le Dréan G, Chaix JC, Puigserver A, Guilloteau P. Bovine pancreatic preproelastases I and II: comparison of nucleotide and amino acid sequences and tissue specific expression. Comp Biochem Physiol B Biochem Mol Biol 1997; 118:181-7. [PMID: 9418008 DOI: 10.1016/s0305-0491(97)00031-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Clones encoding bovine preproelastases I and II were isolated from a pancreatic cDNA library and were sequenced in order to define the structural characteristics of these enzymes. The bovine 947- and 884-nucleotide preproelastase I and II cDNAs encode proteins containing a signal peptide of the same length (16 amino acids), but with a slightly different number of amino acids for the activation peptide (10 and 12, respectively) and the mature enzyme (240 and 241, respectively). Considering amino acid sequences, each enzyme shares a high degree of identity (76-86%) within species. In contrast, only 55.3% identity is found between bovine elastases I and II. This difference could explain partly their own specificity. Analysis of the expression of the elastases in various bovine tissues demonstrated that they are specifically expressed in high levels in the pancreatic gland. These two approaches (structure and expression) allowed us to characterize the bovine pancreatic elastases I and II.
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Affiliation(s)
- M Gestin
- Laboratoire du Jeune Ruminant, I.N.R.A., Rennes, France
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37
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Wyborski DL, DuCoeur LC, Short JM. Parameters affecting the use of the lac repressor system in eukaryotic cells and transgenic animals. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 1996; 28:447-458. [PMID: 8991077 DOI: 10.1002/(sici)1098-2280(1996)28:4<447::aid-em22>3.0.co;2-e] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Elements of the lactose operon were used to study parameters affecting gene expression in cultured cells and transgenic animals. A Lac repressor protein containing a nuclear transport signal was shown to inhibit expression of a reporter gene by interacting with lac operator sequences. In cultured cells, operator sequence, operator placement and induction parameters were all shown to be important for obtaining tight repression of a reporter gene followed by high level expression upon induction. Induction levels were also dependent on the reporter gene, with the luciferase gene yielding higher induction levels than the chloramphenicol acetyltransferase gene. In transgenic animals, the lacI mRNA was not detected in the C57BL/6 mouse strain until the animal was exposed to a demethylating agent. After 5-azacytidine treatment, expression of lacI mRNA was detected in the brain, heart, kidney, lung and ovary. In the FVB transgenic mouse strain, expression of lacI mRNA was detected without 5-azacytidine treatment in the kidney, liver, lung, and testes. Preliminary experiments with double transgenic animals containing both lacI and operator/luciferase transgenes showed a decrease in luciferase expression compared to the luciferase-only animals in both tissue extracts and transgenic fetal primary cultures, although IPTG induction was not achieved in these animals or primary cultures. The applicability and challenges of the system for regulation of gene expression are discussed.
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38
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Larsen HJ, Brodersen CH, Hjorth JP. High-level salivary gland expression in transgenic mice. Transgenic Res 1994; 3:311-6. [PMID: 7951333 DOI: 10.1007/bf01973591] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
A 7.1 kb mini-gene construct containing cloned DNA from the murine parotid secretory protein (PSP) gene with 6.2 kb of the promoter, has previously been shown to direct specific mRNA expression to the salivary glands in transgenic mice. However, the level of transgene expression in the parotid gland was only a few percent of the endogenous level. This indicated that elements necessary for high-level expression are still to be found. In this study, we have searched for such regulatory elements in additional flanking regions by using a 25 kb cloned Pspb fragment containing the complete structural gene, 11.4 kb of 5'-flanking sequence, and 2.5 kb 3'-flanking sequence as a transgene. To distinguish the expression of the transgene from that of the endogenous gene, we took advantage of an allelic difference, using an oligonucleotide that recognized the mRNA from Pspb and the transgene but not that from the other allele, Pspa. The expression of the transgene was examined in animals homozygous for Pspa. Three independent integrations all exhibited a level of parotid-gland-specific expression that corresponded to that of the endogenous gene. Thus, sequences responsible for this high-level PSP mRNA expression are situated within the genomic DNA of the transgene.
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Affiliation(s)
- H J Larsen
- Department of Molecular Biology, University of Aarhus, Denmark
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39
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A single element of the elastase I enhancer is sufficient to direct transcription selectively to the pancreas and gut. Mol Cell Biol 1994. [PMID: 8114736 DOI: 10.1128/mcb.14.3.2048] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The elastase I (EI) gene is expressed at high levels in the exocrine pancreas and at lower levels in other regions of the gut. The transcriptional enhancer of the EI gene, from nucleotides -205 to -72, recapitulates the expression of the endogenous gene in transgenic mice; it directs not only pancreatic acinar cell expression of a human growth hormone (hGH) transgene but also expression to the stomach, duodenum, and colon. This pattern of selective expression limited to the gastroenteropancreatic organ system is specified by the A element, one of three functional elements in the EI enhancer. When multimerized, the A element directed expression of a hGH reporter gene selectively to the pancreas, stomach, and intestine in transgenic mice. Immunofluorescent localization of hGH indicated that the A element multimer transgenes were expressed in the acinar cells of the pancreas as well as in Brunner's gland cells of the duodenum. The A element binds a pancreatic acinar cell-specific factor, PTF1. Our results show that while the A element is responsible for directing tissue and cell type specificity, other elements of the enhancer must be involved in the regulation of the level of gene expression.
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40
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Rose SD, Kruse F, Swift GH, MacDonald RJ, Hammer RE. A single element of the elastase I enhancer is sufficient to direct transcription selectively to the pancreas and gut. Mol Cell Biol 1994; 14:2048-57. [PMID: 8114736 PMCID: PMC358565 DOI: 10.1128/mcb.14.3.2048-2057.1994] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
The elastase I (EI) gene is expressed at high levels in the exocrine pancreas and at lower levels in other regions of the gut. The transcriptional enhancer of the EI gene, from nucleotides -205 to -72, recapitulates the expression of the endogenous gene in transgenic mice; it directs not only pancreatic acinar cell expression of a human growth hormone (hGH) transgene but also expression to the stomach, duodenum, and colon. This pattern of selective expression limited to the gastroenteropancreatic organ system is specified by the A element, one of three functional elements in the EI enhancer. When multimerized, the A element directed expression of a hGH reporter gene selectively to the pancreas, stomach, and intestine in transgenic mice. Immunofluorescent localization of hGH indicated that the A element multimer transgenes were expressed in the acinar cells of the pancreas as well as in Brunner's gland cells of the duodenum. The A element binds a pancreatic acinar cell-specific factor, PTF1. Our results show that while the A element is responsible for directing tissue and cell type specificity, other elements of the enhancer must be involved in the regulation of the level of gene expression.
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Affiliation(s)
- S D Rose
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas 75235-9038
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41
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Le Huerou-Luron I, Lhoste E, Wicker-Planquart C, Dakka N, Toullec R, Corring T, Guilloteau P, Puigserver A. Molecular aspects of enzyme synthesis in the exocrine pancreas with emphasis on development and nutritional regulation. Proc Nutr Soc 1993; 52:301-13. [PMID: 8234352 DOI: 10.1079/pns19930066] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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42
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Affiliation(s)
- J W Gordon
- Department of Obstetrics, Gynecology, and Reproductive Science, Mount Sinai School of Medicine, New York, New York 10029
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43
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44
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45
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Kjer-Nielsen L, Holmberg K, Perera JD, McCluskey J. Impaired expression of chimaeric major histocompatibility complex transgenes associated with plasmid sequences. Transgenic Res 1992; 1:182-7. [PMID: 1301211 DOI: 10.1007/bf02522537] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Plasmid vector sequences were retained (vector+), or removed (vector-) from hybrid major histocompatibility complex gene constructs prior to microinjection of fertilized ova for the production of transgenic mice. In transgenic mice containing integrated vector+ gene constructs, low levels of class II cell surface determinants were detected on splenocytes from only two out of six independent lines. Class II membrane determinants were not detectable on splenocytes from the remaining four vector+ transgenic lines. Expression of transgene products did not correlate with transgene copy number which ranged from 1-10 copies. Low levels of mRNA transcripts were detected in thymic mRNA from vector+ lines. In contrast, high levels of thymic and splenic mRNA transcripts were detected in offspring from all four vector- transgenic lines. Spleen cells from the vector- transgenic animals also expressed high levels of the hybrid major histocompatibility complex transgene products. These results implicate plasmid vector sequences in the inhibition of expression of the hybrid class II-class I major histocompatibility complex genes in transgenic mice. This putative inhibition of transgene expression presumably occurs at the level of gene transcription.
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MESH Headings
- Animals
- Blotting, Northern
- Blotting, Southern
- Crosses, Genetic
- DNA/genetics
- DNA/isolation & purification
- Exons
- Female
- Genes, MHC Class II
- Genetic Vectors
- Histocompatibility Antigens Class II/biosynthesis
- Histocompatibility Antigens Class II/genetics
- Introns
- Major Histocompatibility Complex
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Inbred Strains
- Mice, Transgenic
- Plasmids
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Recombinant Fusion Proteins/biosynthesis
- Restriction Mapping
- Transcription, Genetic
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Affiliation(s)
- L Kjer-Nielsen
- Thymus Biology Unit, Walter and Eliza Hall Institute of Medical Research, Royal Melbourne Hospital, Victoria, Australia
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Norris E, Sanders M, Crumety V, Tsubota SI. The identification of the Bs breakpoint and of two possible Bar genes. MOLECULAR & GENERAL GENETICS : MGG 1992; 233:106-12. [PMID: 1603054 DOI: 10.1007/bf00587567] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Two coding regions were identified within a 110 kb region which includes all mapped Bar breakpoints. Both lie proximal to the identified Bar breakpoints. The first coding region, designated BarA, is 5 kb from the most proximal Bar mutation, B581, and 66 kb from the Bs breakpoint. It encodes a 1.3 kb transcript, which is found in late third instar larvae but is absent in 1-3-day-old pupae. Bi, R(B)hd3, B85c15, and Bs result in overproduction of this transcript in late third instar larvae. A second coding region, which was previously identified as BarH1, maps 18 kb from B581 and 79 kb from the Bs breakpoint. In third instar larvae, the abundance of the BarH1 transcript is very low in both wild type and various Bar mutatants, with the exception of R(B)hd3. In 1-3-day-old pupae, the level of the BarH1 transcript is higher. BarH1 was previously identified as the Bar gene. However, this report raises the possibility that BarA rather than BarH1 is the Bar gene or that more than one gene may be involved in Bar position effects.
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Affiliation(s)
- E Norris
- Department of Biology, University of Michigan, Ann Arbor 48109
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47
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48
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Exocrine pancreas transcription factor 1 binds to a bipartite enhancer element and activates transcription of acinar genes. Mol Cell Biol 1991. [PMID: 1717824 DOI: 10.1128/mcb.11.10.4985] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Exocrine pancreas (XP) enhancers, which contain a conserved core sequence, are active only in XP cells. A core enhancer-binding activity also appears to be restricted to XP nuclei. Here we describe the properties of a factor, purified approximately 100,000-fold from pancreas nuclei, which displays core enhancer-binding activity. It is not identical to previously characterized factors and is termed exocrine pancreas transcription factor 1 (XPF-1). In the highly purified preparation, only a single major protein of 60 kDa was detected by silver staining on sodium dodecyl sulfate-gels and by UV cross-linking. XPF-1 binds to the core enhancer of all tested XP genes and not to a mutant sequence which is inactive in vivo. High-affinity binding sites are bipartite. The results of competition binding and UV-cross-linking assays suggest that XPF-1 interacts with both motifs. XPF-1 selectively stimulates transcription of core enhancer templates in an in vitro transcription system. We hypothesize that XPF-1 plays a role in activation of the transcription of XP-specific genes.
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49
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Weinrich SL, Meister A, Rutter WJ. Exocrine pancreas transcription factor 1 binds to a bipartite enhancer element and activates transcription of acinar genes. Mol Cell Biol 1991; 11:4985-97. [PMID: 1717824 PMCID: PMC361483 DOI: 10.1128/mcb.11.10.4985-4997.1991] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Exocrine pancreas (XP) enhancers, which contain a conserved core sequence, are active only in XP cells. A core enhancer-binding activity also appears to be restricted to XP nuclei. Here we describe the properties of a factor, purified approximately 100,000-fold from pancreas nuclei, which displays core enhancer-binding activity. It is not identical to previously characterized factors and is termed exocrine pancreas transcription factor 1 (XPF-1). In the highly purified preparation, only a single major protein of 60 kDa was detected by silver staining on sodium dodecyl sulfate-gels and by UV cross-linking. XPF-1 binds to the core enhancer of all tested XP genes and not to a mutant sequence which is inactive in vivo. High-affinity binding sites are bipartite. The results of competition binding and UV-cross-linking assays suggest that XPF-1 interacts with both motifs. XPF-1 selectively stimulates transcription of core enhancer templates in an in vitro transcription system. We hypothesize that XPF-1 plays a role in activation of the transcription of XP-specific genes.
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Affiliation(s)
- S L Weinrich
- Department of Biochemistry and Biophysics, University of California, San Francisco 94143-0534
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50
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Abstract
This chapter is an attempt to summarize some commonly accepted and some more subjective opinions about the regulation of transgene expression in laboratory animals. After a short historical introduction, I present some general notions regarding gene structure/function. The spotlight shifts then to the description of the most popular techniques for gene transfer, including the targeted gene replacement. The different approaches are briefly discussed in terms of intrinsic advantages and limitations regarding gene expression patterns. Furthermore, the role of enhancers, promoters and other cis-acting elements such as silencers and dominant control regions as well as their involvement in the chromatin on-off state are discussed on the basis of a specific example studied in our laboratory. The review concludes by presenting recent results and the new perspectives opening in the field of 'surrogate' (also called 'reversed') genetics. Some problems which remain to be solved both at the technical as well as at the social-ethical level are also briefly presented.
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Affiliation(s)
- S Rusconi
- Institut für Molekularbiologie II der Universität Zürich, Switzerland
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