Molecular Control Of Cell Proliferation In Early Mouse Development
Funder
National Health and Medical Research Council
Funding Amount
$338,009.00
Summary
Elucidation of cell cycle regulation in the proliferating pluripotent cells of the early mammalian embryo is likely to have important impact on basic scientific knowledge, and on the development of novel therapeutic strategies. Investigation of this problem, in vitro and in vivo, requires specialist skills in cell cycle analysis, and experimental manipulation of mammalian embryos and pluripotent cells. This application will seek to address these fundamental issues of early development and cell p ....Elucidation of cell cycle regulation in the proliferating pluripotent cells of the early mammalian embryo is likely to have important impact on basic scientific knowledge, and on the development of novel therapeutic strategies. Investigation of this problem, in vitro and in vivo, requires specialist skills in cell cycle analysis, and experimental manipulation of mammalian embryos and pluripotent cells. This application will seek to address these fundamental issues of early development and cell proliferation using molecular approaches. The general aims will be: 1. to obtain a detailed description of cell cycles in pluripotent and differentiating cells of the mouse embryo 2. use this information to build a molecular description of cell cycle events during early embryogenesis 3. investigate the relationship between rapid cell proliferation in the embryo and pluripotencyRead moreRead less
Cell death by a special process called apoptosis is a means of deleting unwanted and harmful cells from the body. Extensive apoptosis occurs during foetal development which is required to get rid of many excess cells produced during the growth of the embryo. Selective apoptosis is also essential for the formation of different tissues and organs in developing foetus. In the adult, apoptosis is required for proper functioning of the immune system, to remove virus infected and cancer cells and, in ....Cell death by a special process called apoptosis is a means of deleting unwanted and harmful cells from the body. Extensive apoptosis occurs during foetal development which is required to get rid of many excess cells produced during the growth of the embryo. Selective apoptosis is also essential for the formation of different tissues and organs in developing foetus. In the adult, apoptosis is required for proper functioning of the immune system, to remove virus infected and cancer cells and, in general, to maintain the correct number of cells in the body. As such, misregulation of apoptosis is associated with the pathogenesis of a wide array of diseases. To understand, manage and treat disorders that result from aberrant apoptosis, we need to know at molecular and cellular level, how apoptosis is brought about and how it is regulated. We have been studying these processes in detail for several years. Central to the apoptotic execution of cell death are a group of proteases called caspases, that target many cellular proteins for specific cleavage. The activation of caspases is the crucial step in the initiation of apoptosis and therefore each cell has developed complex ways to control this process. If we understand how these regulatory mechanisms operate, we can then formulate strategies that are targeted towards pathologies involving abnormal apoptosis. In this proposal we will use vinegar fly as a model to study the function of caspases in development. We believe that results from this proposal will have several major benefits. Firstly, they will provide important insight into the mechanisms of developmental apoptosis thereby filling many gaps in our current knowledge. Secondly, the study will endeavour to identify new molecules-pathways that lead to caspase activation. Finally, the proposed studies will shed light on the function of caspases in non-apoptotic pathways.Read moreRead less
Understanding how the brain grows and is organised is one of the great challenges of science. This project seeks to identify key regulators of neural progenitors as these are the building blocks from which all brains cells are derived. This knowledge may also identify new avenues through which to manipulate neural progenitor function. This has implications not only for normal brain development but also potential therapies for neural disorders and disease.
This is a study of the biological system of epigenetics. Every cell in our body has the same genetics, or library of information contained in the form of DNA sequence. Epigenetics is the system that controls how this DNA is used in a particular situation, or what books are opened and read. During embryonic development, cells know what they want to become, e.g., a muscle cell, and, once they take on an identity, remember that they are when they duplicate themselves during growth. Epigenetics does ....This is a study of the biological system of epigenetics. Every cell in our body has the same genetics, or library of information contained in the form of DNA sequence. Epigenetics is the system that controls how this DNA is used in a particular situation, or what books are opened and read. During embryonic development, cells know what they want to become, e.g., a muscle cell, and, once they take on an identity, remember that they are when they duplicate themselves during growth. Epigenetics does not achieve this through changing genetics the library always stays intact. Rather, it acts by using proteins or chemicals to make DNA functional in one way, or another. Genomic imprinting is a special type of epigenetics. While an embryo has received identical genetic information from each of its parents, the epigenetic information received from each parent was not entirely the same. Some genes which behave differently according to what parent they came from. For example, a gene that makes a growth factor protein is active only if received from the father. If received from the mother, it is inactive, and makes no protein. Genes behaving in this way are known as imprinted genes. We are trying to discover what epigenetic mechanisms are behind this behaviour of imprinted genes. One way we are approaching this problem is to study germ cells the cells giving rise to eggs and sperm. These cells are unusual in that their imprinted genes behave in the same way regardless of whether they were received from the mother or father, i.e., like any other gene. If we can understand why this is the case, we will be better able to understand why imprinted genes behave the way they do in the rest of the cells of the body. Broadly, the mechanisms we uncover should further our understanding of germ cell development, gene expression, and disease. Perturbations in the epigenetic profile are likely causes of human disease, including cancer.Read moreRead less
The Function Of Transcription Factor SCL In T Cell Development.
Funder
National Health and Medical Research Council
Funding Amount
$504,750.00
Summary
SCL is a gene which is abnormally expressed in a large percentage of human T cell leukaemias. Mouse models that increase SCL levels have demonstrated that T cell maturation is abnormally affected by SCL. Thus, providing a clue as to how T cell leukemias arise. By utilising recombinant DNA technology we are now able to control SCL levels in T cell maturation. We can either increase the level of SCL using pharmacological reagents or we can genetically remove SCL from maturing T cells. This double- ....SCL is a gene which is abnormally expressed in a large percentage of human T cell leukaemias. Mouse models that increase SCL levels have demonstrated that T cell maturation is abnormally affected by SCL. Thus, providing a clue as to how T cell leukemias arise. By utilising recombinant DNA technology we are now able to control SCL levels in T cell maturation. We can either increase the level of SCL using pharmacological reagents or we can genetically remove SCL from maturing T cells. This double-edged approach will allow us to monitor the effects of SCL on maturing T cells with a precision that has never previously been achieved. Results from this approach will provide new insights into how T cell leukaemia develops and provide the foundation for new rational based treatments.Read moreRead less
The Role Of C-Cbl In The Regulation Of T Cell Signalling And Development
Funder
National Health and Medical Research Council
Funding Amount
$527,250.00
Summary
c-Cbl is a member of a multi-adaptor protein family that can interact with many signalling proteins via its different domains. Cbl proteins have been implicated as negative regulators of signalling pathways involving protein tyrosine kinases (PTKs). PTKs are enzymes which add phosphate groups to tyrosine residues on other protein substrates, and the process of tyrosine phosphorylation acts as a potent biochemical switch to turn signalling cascades on and off. Studies of Cbl-deficient (knockout) ....c-Cbl is a member of a multi-adaptor protein family that can interact with many signalling proteins via its different domains. Cbl proteins have been implicated as negative regulators of signalling pathways involving protein tyrosine kinases (PTKs). PTKs are enzymes which add phosphate groups to tyrosine residues on other protein substrates, and the process of tyrosine phosphorylation acts as a potent biochemical switch to turn signalling cascades on and off. Studies of Cbl-deficient (knockout) mice show that Cbl proteins are important in regulating the development of, and signalling by, cells of the immune system called T cells. c-Cbl knockout mice show greatly enhanced PTK-signalling responses and deregulated activity of a PTK called ZAP-70. The mechanism of this is not known, but analysis of a c-Cbl mutant mouse shows that this is not dependent on the tyrosine kinase binding (TKB) domain of c-Cbl. Therefore other functional domains of Cbl must be responsible for the increased signalling response in the c-Cbl knockout mouse. One candidate is the highly conserved RING finger domain which can modify Cbl-associated PTKs by addition of ubiquitin molecules. Ubiquitination of a protein often, but not always, leads to its degradation, and this could be how Cbl controls the strength and duration of signalling in T cells. However there may be other functions of the conserved RING finger yet to be identified. c-Cbl itself is prominently and very rapidly modified by tyrosine phosphorylation on tyrosine 737 by the Fyn PTK following T cell activation, but the role of this modification is not known and could also be essential for c-Cbl s function in T cells. We plan to investigate the roles of the RING finger domain and Fyn-mediated tyrosine phosphorylation in c-Cbl regulation of T cell signalling by analyzing knock-in mice that carry specific mutations disrupting the RING finger or tyrosine 737 in the c-Cbl gene.Read moreRead less
Kidney Mesenchymal Stem Cells In Tubular Development, Repair And Turnover.
Funder
National Health and Medical Research Council
Summary
In Australia, 11.3% of deaths are associated with chronic kidney disease with >$1 billion per annum spent on treating this condition. At present, only dialysis and transplantation are available to treat end stage kidney disease. We have found a kidney stem cell population in both human and mouse that can form new epithelial structures. In this project, we will investigate the normal role played by these kidney stem cells and examine whether they can contribute to kidney regeneration.
Discovery Of Novel T Cell Oncogenes By Using A Functional Retroviral CDNA Library Screen.
Funder
National Health and Medical Research Council
Funding Amount
$692,470.00
Summary
T cells mature in an organ called the thymus which is located on top of the heart. Blood borne T cell precursors enter the thymus after being resident in the bone marrow. T cell leukaemia is a disease where a blood cell that is committed to becoming a T cell is blocked from maturing into a functional cell. Instead, the leukaemic immature T cell uncontrollably divides to make endless non-functional copies of itself. As a result, normal functional T cells are outcompteted and the immune system is ....T cells mature in an organ called the thymus which is located on top of the heart. Blood borne T cell precursors enter the thymus after being resident in the bone marrow. T cell leukaemia is a disease where a blood cell that is committed to becoming a T cell is blocked from maturing into a functional cell. Instead, the leukaemic immature T cell uncontrollably divides to make endless non-functional copies of itself. As a result, normal functional T cells are outcompteted and the immune system is crippled. Patients generally die due to opportunistic infection. The molecular causes of T cell leukaemia are slowly being discovered. Up to 50% of all human T cell leukaemias overexpress SCL-TAL-1. Other T cell leukaemia-causing genes (oncogenes) include Ras and Notch. Current leukaemia treatments include chemotherapy and bone marrow transplants but even these fail ~30% of the time. Consequently, all T cell oncogenes need to be discovered so that disease-specific treatments can be generated. This proposal will utlise a functional retroviral cDNA library screen to uncover novel T cell lineage commitment genes and T cell oncogenes. This will be accomplished by constructing a coloured [GFP] cDNA library (a library of genes) that will be transfected (inserted) into immature T cells that cannot develop down the T cell pathway owing to the lack of a crucial gene (Rag-1). The T cell oncogene Ras and the T cell lineage commitment gene Notch can move cells past the Rag-1 block. If there is a gene in the cDNA library that can compensate for the lack of Rag-1 and allow the cells to mature we will detect it using high speed flow cytometryic cell sorting (like sieving weevils from flour very quickly). Once we find this cell we will isolate the gene using the colour tag. The potential oncogenes uncovered will provide the foundation for next generation drug development that targets each leukaemia based on its cause.Read moreRead less
Evolutionary Conservation Of Caspase Regulatory Mechanisms
Funder
National Health and Medical Research Council
Funding Amount
$585,215.00
Summary
Apoptosis is a highly controlled process by which metazoans eliminate unwanted and dangerous cells. Dysregulation of apoptosis can contribute to many conditions including cancer, autoimmune and degenerative diseases. To develop therapeutic reagents that promote cell death when it fails to occur, or prevent it from happening inappropriately, it is necessary to understand the mechanisms controlling apoptosis. To date, many of the important insights into mammalian cell death signalling have been in ....Apoptosis is a highly controlled process by which metazoans eliminate unwanted and dangerous cells. Dysregulation of apoptosis can contribute to many conditions including cancer, autoimmune and degenerative diseases. To develop therapeutic reagents that promote cell death when it fails to occur, or prevent it from happening inappropriately, it is necessary to understand the mechanisms controlling apoptosis. To date, many of the important insights into mammalian cell death signalling have been informed by studies of apoptotic pathways in simpler, experimentally tractable model organisms. This project will exploit biochemical approaches and powerful yeast-based tools developed by CI-A to further explore cell death pathways of the nematode Caenorhabditis elegans, and compare these with mammalian apoptosis pathways. Key findings will be verified using genetic approaches. Most apoptotic stimuli ultimately kill mammalian, insect or nematode cells by triggering activation of proteases termed caspases. However, the mechanisms by which caspase activity is regulated appear to differ somewhat between mammals and worms. We will address two general possibilities: either these animals really do differ significantly in the upstream regulation of cell death pathways, or that functional counterparts of key components have not hitherto been identified or fully characterised. Understanding the way in which mammalian apoptosis is regulated will aid in the design of diagnostic and therapeutic reagents for the many diseases in which dysregulation of apoptosis has been implicated. This project seeks to define the extent to which apoptotic regulation is conserved between mammals and nematodes. This knowledge will enable researchers to maximise the utility of nematode cell death models for the further elucidation of mammalian cell death regulatory mechanisms, and to explore how apoptosis can be manipulated for clinical benefit.Read moreRead less
Evaluation Of Immune Correlates For Virus-specific CD8+ T Cells Following Prime-boost Vaccination
Funder
National Health and Medical Research Council
Funding Amount
$397,889.00
Summary
This project will use cutting-edge technology to evaluate the quality of virus-specific white blood cells generated following vaccination. Clinically relevant vaccination strategies will be analysed in a well characterised mouse model of infection to produce correlates associated with protective vaccine efficacy, particularly in an immunosupressed setting. This will lead to more focused research and ultimately the development of prophylactic and therapeutic HIV vaccines.