Molecular Mechanisms For The Cell-type Specific Regulation Of The Tissue-type Plasminogen Activator Gene
Funder
National Health and Medical Research Council
Funding Amount
$490,500.00
Summary
Tissue-type plasminogen activator (t-PA) is an important enzyme that is widely known for its ability to remove blood clots. More recently, t-PA has been shown to influence memory development and under pathological conditions can promote neuronal cell death. t-PA is produced by many cells including the endothelial cells that line the blood vessels, fibroblasts, as well as cells within the central nervous system. The t-PA gene is regulated very differently in these cell types and this project will ....Tissue-type plasminogen activator (t-PA) is an important enzyme that is widely known for its ability to remove blood clots. More recently, t-PA has been shown to influence memory development and under pathological conditions can promote neuronal cell death. t-PA is produced by many cells including the endothelial cells that line the blood vessels, fibroblasts, as well as cells within the central nervous system. The t-PA gene is regulated very differently in these cell types and this project will address the mechanisms underlying the cell-type specific regulation of the t-PA gene. Endothelial cells, fibroblasts and neuronal cell cultures will be used to study the regulation of t-PA expression. Information gained will not only add to the understanding of the broader field of gene regulation, but may also provide clues to manipulate the expression of the t-PA gene in different cells.Read moreRead less
Epigenomic Marks As Indicators Of The Kinetics Of Gene Activation In Immune Cells.
Funder
National Health and Medical Research Council
Funding Amount
$619,805.00
Summary
Switching on an immune response involves major changes in the gene expression program of the immune cells. These changes in gene expression take place in the context of DNA packaged into the nucleus in a structure known as chromatin. We will investigate the relationship between chromatin and gene expression changes and how this relationship plays a role in the timing of the immune response. This information will be useful in developing novel means of controlling aberrant immune responses.
Retrotransposons As Controlling Elements In Mammals: A Screen For Expression In Somatic Cells And Cancer
Funder
National Health and Medical Research Council
Funding Amount
$452,545.00
Summary
Differences between individual mammals are generally thought to be due to differences either between their genes, or between their environments. However, in many cases genetic or environmental factors cannot account for differences between individuals. We have studied mice in which dramatic differences between genetically identical individuals are due solely to the activity of a type of transposable element (transposon). There are tens of thousands of similar elements in the genomes of all mamma ....Differences between individual mammals are generally thought to be due to differences either between their genes, or between their environments. However, in many cases genetic or environmental factors cannot account for differences between individuals. We have studied mice in which dramatic differences between genetically identical individuals are due solely to the activity of a type of transposable element (transposon). There are tens of thousands of similar elements in the genomes of all mammals. A large body of evidence demonstrates that transposons can disrupt gene expression. To prevent this from occurring, most organisms have evolved mechanisms to keep transposons silent. However, fragmentary evidence indicates that transposons are at least sometimes expressed in normal and cancer cells. We hypothesize that activity of transposons in mammals alters gene expression sufficiently to cause variation between individuals, and that altered gene expression can cause disease (particularly cancer) and some manifestations of aging. As a first step toward testing this hypothesis, it is essential to acquire more complete information on the expression of transposons in normal and diseased cells. Furthermore, if transposon expression is closely linked to the development or progression of cancer or aging, then the ability to monitor such expression could have diagnostic utility. DNA array technology is coming into wide use to compare patterns of gene expression in different types of cells. We propose to adapt this method to the study of transposon expression. We will clone examples of all known classes of mouse and human transposon, and study transposon expression in: 1. Normal mice, at intervals from the earliest phase of development to old age, and 2. Human cancers of a variety of types. These studies will provide information of fundamental significance for mammalian biology, and also have the potential to lead to improved diagnosis of disease.Read moreRead less
In Vivo And In Vitro Studies Of The Human -308 TNF Promoter Polymorphism.
Funder
National Health and Medical Research Council
Funding Amount
$232,131.00
Summary
The identification of genetic variation in region of the DNA that controls expression of the inflammatory cytokine Tumour Necrosis Factor (TNF) and its association with a number of autoimmune and inflammatory diseases, has led to speculation that this genetic difference may play a role in predisposing some people to these diseases. We have isolated an activity, TPF1, that may regulate expression through interaction with this DNA control region. During the tenure of this grant we intend to clarif ....The identification of genetic variation in region of the DNA that controls expression of the inflammatory cytokine Tumour Necrosis Factor (TNF) and its association with a number of autoimmune and inflammatory diseases, has led to speculation that this genetic difference may play a role in predisposing some people to these diseases. We have isolated an activity, TPF1, that may regulate expression through interaction with this DNA control region. During the tenure of this grant we intend to clarify some of these questions, we will generate genetically modified mice that have either of the two genetic forms of the human TNF promoter. These mice will be compared in two models of associated disease, murine Lupus and cerebral malaria. We will also characterise the interactions of TPF1 with other components of the TNF control region. An understanding of the role of TPF1 in controlling TNF expression and an appreciation of the cell types that are able to express the phenotype, will allow the development of more subtle, cell specific strategies to modulate the activity of TNF without completely abolishing expression and may lead to better preventative and therapeutic strategies.Read moreRead less
Gene Transcription In Activated T Cells: A Model Of Chromatin Remodeling.
Funder
National Health and Medical Research Council
Funding Amount
$477,500.00
Summary
Cells of the immune system respond to invasion of the body by infectious or other damaging agents by switching on the production of a large array of proteins that are critical for an orchestrated immune response. Some of these proteins, referred to as cytokines, are secreted by the cells and act as intercellular messengers to affect the function of other cells need for an immune response. Switching on the production of these cytokines requires the genes that produce them to interpret the complex ....Cells of the immune system respond to invasion of the body by infectious or other damaging agents by switching on the production of a large array of proteins that are critical for an orchestrated immune response. Some of these proteins, referred to as cytokines, are secreted by the cells and act as intercellular messengers to affect the function of other cells need for an immune response. Switching on the production of these cytokines requires the genes that produce them to interpret the complex signaling pattern to which the cell has been exposed. These complex signaling patterns are interpreted in the nucleus by molecular switches that lie beside the genes in the DNA. The incorrect production of these proteins is involved in immune diseases such as autoimmunity, allergy and leukemia. Genes are housed in the nucleus of the cell, packaged into a structure known as chromatin. When the gene is not producing protein it is tightly packaged in chromatin but when it is activated to produce protein this packaging is altered to allow the gene to see the signals being received by the cell and produce protein. We have identified a protein within the nucleus that is critical in allowing certain cytokine genes to see the signals being received in the nucleus. By investigating the role of this protein (called c-Rel) in chromatin reorganization in immune cells, we hope to better define the steps required for appropriate gene activation in an immune response. This knowledge, in turn, will lead to the identification of novel therapeutic targets to control immune responsesRead moreRead less
A Comprehensive Analysis Of Myb Target Genes Involved In Myelopoiesis And Myeloid Transformation
Funder
National Health and Medical Research Council
Funding Amount
$511,294.00
Summary
The MYB gene is essential for both normal blood cell formation and the growth of leukaemia cells. It acts by switching other genes (target genes) on and off. This project aims to advance our understanding of how MYB functions, by carrying out a comprehensive search for MYB target genes. In particular it will focus on target genes that help explain MYB's ability to control cellular growth and maturation. Some of these target genes may provide leads for future anti-cancer drug development.
Post-transcriptional Regulation Of Plasminogen Activator Inhibitor 2 Gene Expression
Funder
National Health and Medical Research Council
Funding Amount
$508,838.00
Summary
Plasminogen activator inhibitor type 2 (PAI-2) is a protease inhibitor that has intracellular and extracellular functions. The PAI-2 gene is highly regulated at the level of PAI-2 mRNA stability. We have identified regions within the PAI-2 transcript essential for this regulation and a number of novel proteins that engage these regions. This project is aimed at understanding how these and other proteins control PAI-2 expression at the mRNA level.
Effects Of The Atrial Natriuretic Factor Enhancer And The 5'HS4 Insulator On The Probability Of Gene Expression.
Funder
National Health and Medical Research Council
Funding Amount
$534,628.00
Summary
Complex organisms contain many different types of cells, which can have completely different appearances and functions. All of these cells contain the same genes; the differences between them are achieved by the selective use of the genes. The means by which the selective use of genes is accomplished is a key to understanding how complex organisms develop, and how that development goes awry in cancer, heart disease, and other common disorders. A very large body of evidence indicates that gene re ....Complex organisms contain many different types of cells, which can have completely different appearances and functions. All of these cells contain the same genes; the differences between them are achieved by the selective use of the genes. The means by which the selective use of genes is accomplished is a key to understanding how complex organisms develop, and how that development goes awry in cancer, heart disease, and other common disorders. A very large body of evidence indicates that gene regulation is accomplished by the interaction of protein factors with segments of DNA flanking the gene. One hypothesis underlying our work is that the flanking DNA elements act primarily to increase the probability that a gene will be active rather than silent. We will ask if removing a known regulatory element from the gene for Atrial Natriuretic Factor (ANF) in mice reduces the likelihood of ANF being expressed by heart cells when the heart is stressed. This experiment will also shed new light on an extremely common disease state in humans (cardiac hypertrophy). In a second experiment, we will use a new experimental system we have developed to ask if a gene regulatory element is able to dial up the amount of expression from a gene, as well as to switch the gene on. Our previous work suggested this was not the case, but we wish to conduct a more rigorous test. Another hypothesis is that no DNA element is able to completely shield a transferred gene from the regulatory elements surrounding it. Accordingly, we will test a DNA element that has been proposed to insulate any gene from all influences of surrounding genes, and ask if it is able to create an autonomously expressing gene at any site within the genome. Because they deal with functions that are common to all genes, these experiments will provide information that should be applicable to a broad array of efforts to manipulate gene expression.Read moreRead less
STUDIES OF NF-E4, A NOVEL FETAL/ERYTHROID SPECIFIC FACTOR INVOLVED IN FETAL GLOBIN GENE REGULATION
Funder
National Health and Medical Research Council
Funding Amount
$753,810.00
Summary
Sickle cell anemia and thalassemia are the commonest genetic disorders worldwide. Those affected suffer devastating clinical sequelae and mortality in the first twenty years of life remains high. A cure for these diseases is dependent on the replacement of the affected or absent hemoglobin protein chains with normally functioning hemoglobins. This is evident in rare patients who co-inherit a natural mutation which elevates fetal hemoglobin (HbF), as these patients have a dramatically ameliorated ....Sickle cell anemia and thalassemia are the commonest genetic disorders worldwide. Those affected suffer devastating clinical sequelae and mortality in the first twenty years of life remains high. A cure for these diseases is dependent on the replacement of the affected or absent hemoglobin protein chains with normally functioning hemoglobins. This is evident in rare patients who co-inherit a natural mutation which elevates fetal hemoglobin (HbF), as these patients have a dramatically ameliorated clinical course. Therefore, treatment strategies which could reactivate fetal globin gene expression after birth should be explored for these diseases. To achieve this goal we must further our understanding of the normal mechanisms of developmental regulation of globin gene expression. To this end we have recently identified a novel gene which is critical for fetal globin expression. The studies we propose here will further define the function of this gene and assess its potential for gene therapy for sickle cell disease and thalassemia.Read moreRead less
Regulation Of Tissue-type Plasminogen Activator Gene Expression In Endothelial Cells And In Transgenic Mice
Funder
National Health and Medical Research Council
Funding Amount
$244,009.00
Summary
Tissue-type plasminogen activator (t-PA) is an enzyme which plays an important role in the removal of blood clots from the circulation. One of the major sites of production of t-PA are endothelial cells which line the blood vessel wall. The rate of t-PA production is greatly influenced by factors released from other cells. One of these factors is tumour necrosis factor (TNF). The t-PA gene is switched off in endothelial cells exposed to TNF. One of the aims of this project is to understand how t ....Tissue-type plasminogen activator (t-PA) is an enzyme which plays an important role in the removal of blood clots from the circulation. One of the major sites of production of t-PA are endothelial cells which line the blood vessel wall. The rate of t-PA production is greatly influenced by factors released from other cells. One of these factors is tumour necrosis factor (TNF). The t-PA gene is switched off in endothelial cells exposed to TNF. One of the aims of this project is to understand how the t-PA gene is suppressed by TNF in human endothelial cells and in transgenic mice. The transgenic mice we have available express the regulatory region of the t-PA gene (called the gene promoter) connected to a reporter gene called LacZ. We will use these animals to visualise the expression pattern of LacZ expression under normal conditions and in mice treated with TNF. The results of these experiments will provide new information as to how the t-PA gene is controlled in cells and in the body.Read moreRead less