All cells in the blood are the descendants of a single cell type, the stem cell. Stem cells are found in the bone marrow and throughout life have the unique ability to generate more of themselves (termed self-renewal) as well as to produce the functional cell types of the blood, ie. red and white blood cells. This project concentrates on the processes by which these stem cells can achieve these two functions. What are the genes that enable a stem cell to have this self-renewal characteristic and ....All cells in the blood are the descendants of a single cell type, the stem cell. Stem cells are found in the bone marrow and throughout life have the unique ability to generate more of themselves (termed self-renewal) as well as to produce the functional cell types of the blood, ie. red and white blood cells. This project concentrates on the processes by which these stem cells can achieve these two functions. What are the genes that enable a stem cell to have this self-renewal characteristic and conversely what are the genes that are activated when a cell becomes committed to become, for example, a white blood cell ? We have identified a gene, Pax5, which is essential in the process whereby a stem cell commits to become a lymphocyte . Our aim is to understand the function of Pax5 as a model for understanding how the commitment process as a whole works in the blood. These studies, as well as having an underlying fundamental scientific importance, are relevant to the clinical development of a number of stem cell therapies which rely on boosting stem cell production in procedures such as bone marrow transplantation for leukaemia and immune deficiency. In addition a number of characterised human blood malignancies indicate that inappropriate lineage commitment may be a factor in cancer.Read moreRead less
Epigenetic Silencing Of Retroelements In Mammalian Stem Cells: A Role For RNA Interference?
Funder
National Health and Medical Research Council
Funding Amount
$296,980.00
Summary
Now that the human genome has been sequenced, all the genes which encode the bricks and mortar of our cells have been defined. A major question remains: how are all these genes controlled and co-ordinated? What turns them on or off at precisely the right time? In this project we wish to test whether a newly-discovered mechanism of turning genes off in plants and flies also works in mammals. If we demonstrate this mechanism then it may help us to improve gene therapy - a novel form of medical tre ....Now that the human genome has been sequenced, all the genes which encode the bricks and mortar of our cells have been defined. A major question remains: how are all these genes controlled and co-ordinated? What turns them on or off at precisely the right time? In this project we wish to test whether a newly-discovered mechanism of turning genes off in plants and flies also works in mammals. If we demonstrate this mechanism then it may help us to improve gene therapy - a novel form of medical treatment in which healthy genes are used to replace defective genes in cells. Both inherited diseases, like hemophilia, and acquired diseases, like cancer, have been considered appropriate targets for gene therapies. Surprisingly, however, the promises of gene therapy have not kept up with expectations. In attempting to achieve clinically relevant results, viruses (masters of forcing infected cells to do their bidding) have been harnessed to deliver healthy genes into diseased cells. A major problem has been that the modified, safe viruses used clinically have not been efficient at achieving sustained production of healthy gene products. In examining the question of what turns gene off, we will attack the problem of sustainability of gene therapy by defining the mechanisms involved in switching gene therapy viruses off. If we can understand what switches viral genes off in cells, then we should be able to devise means to avoid the 'off switch' and thereby provide durable treatments for many types of cancer. In the studies described , we will attack this problem using a number of different, but complementary approaches.Read moreRead less
Regulation Of Adult Colonic Crypt Homeostasis And Activation Of Colon Cancer Metastasis Genes By C-Myb
Funder
National Health and Medical Research Council
Funding Amount
$666,116.00
Summary
Regulation of normal colon biology and activation of genes involved colon cancer The c-myb gene is essential for the normal biology of the blood system and the colon. This gene is involved in regulating the balance between the production of new cells and their timely removal once they have completed their assigned tasks. There is a large body of evidence that supports the role of c-myb in the regulation of the blood system. We believe that the rules that govern the production of the huge number ....Regulation of normal colon biology and activation of genes involved colon cancer The c-myb gene is essential for the normal biology of the blood system and the colon. This gene is involved in regulating the balance between the production of new cells and their timely removal once they have completed their assigned tasks. There is a large body of evidence that supports the role of c-myb in the regulation of the blood system. We believe that the rules that govern the production of the huge number of cells needed to have a healthy blood system are similar if not identical to the rules used by the colon. This is because the colon also produces a massive number of cells each with special tasks and a defined life span of a few days. It is this rapid expansion of cell numbers and the programmed short life span of cells that necessitates multiple controls and very tight regulation. Furthermore if this process is hijacked by genetic changes that undermine these controls then there are numerous opportunities to initiate and potentiate malignant change or cancer. This project examines the role of the same genes in two contexts. Firstly when the genes are expressed at normal, highly regulated levels associated with the normal biology of the colon. The second context is when these genes are permitted to be over-expressed and thus drive processes for longer or in inappropriate situations leading to malignant growth.Read moreRead less
The Establishment Of Epigenetic Marks At Metastable Epialleles In The Mouse
Funder
National Health and Medical Research Council
Funding Amount
$372,750.00
Summary
Occasionally, identical twins are found to have distinctly different characteristics, such as eye colour or severity of genetic disease, that clearly cannot be explained by their genetic makeup, and are unlikely to be the result of environmental differences. In genetically identical mice, similar cases exist, where some mice have a yellow coat and others a brown coat. In instances such as these, a growing body of evidence suggests that certain modifications to genes are responsible. These modifi ....Occasionally, identical twins are found to have distinctly different characteristics, such as eye colour or severity of genetic disease, that clearly cannot be explained by their genetic makeup, and are unlikely to be the result of environmental differences. In genetically identical mice, similar cases exist, where some mice have a yellow coat and others a brown coat. In instances such as these, a growing body of evidence suggests that certain modifications to genes are responsible. These modifications are not traditional DNA mutations, but are chemical modifications of the basic sequence. Currently, we do not know when these DNA modifications are established during foetal development. We will use the mouse coat colour gene mentioned above to investigate when the different physical characteristics are established in embryonic development. Indeed, there is increasing evidence that critical periods exist in human foetal development where minor environmental or nutritional changes can affect long-term health of the adult. Perhaps the establishment of the DNA modifications are under an environmental or nutritional influence. Further study of when and how the DNA modifications are set-up during embryonic development is necessary in order to understand these events.Read moreRead less
A Random Mutagenesis Screen To Identify Modifiers Of Epigenetic Phenomena In The Mouse.
Funder
National Health and Medical Research Council
Funding Amount
$680,750.00
Summary
In recent months, both the human and mouse genome projects have been completed. The main focus now for mammalian geneticists is to discover the function of the genes sequenced in these initiatives. One way to achieve this goal is by random mutagenesis followed by screening of mice for novel phenotypes. In the mouse, ethylnitosourea (ENU) is a chemical that can be used to perform the mutagenesis. ENU causes mutations in sperm. We are using ENU mutagenesis to search for genes that modify epigeneti ....In recent months, both the human and mouse genome projects have been completed. The main focus now for mammalian geneticists is to discover the function of the genes sequenced in these initiatives. One way to achieve this goal is by random mutagenesis followed by screening of mice for novel phenotypes. In the mouse, ethylnitosourea (ENU) is a chemical that can be used to perform the mutagenesis. ENU causes mutations in sperm. We are using ENU mutagenesis to search for genes that modify epigenetic states. Epigenetic modifications are alterations in the genome that do not change the DNA sequence, yet silence the expression of genes. Silencing occurs on a cell-by-cell basis within a tissue resulting in mosaic expression. Silencing can also occur between individuals of the same genetic makeup. For example, identical twins are occasionally found that have distinctly different characteristics, such as eye colour or severity of genetic disease. These differences may be the result of variable epigenetic modifications. However, very little is known about how these variable epigenetic modifications are controlled. We wish to find the proteins involved in establishing and maintaining epigenetic states. It is likely that these processes play a fundamental role in the determination of phenotype, both in normal development and disease.Read moreRead less
Oxidative Damage and Cell Ageing. This research will benefit Australia by providing a fundamental understanding of how cells age. This will have immediate international impact at the scientific level and will inform strategies to reduce the rate of ageing and alleviation of age-related disorders. In the longer term the research may provide commercial and social outcomes by identifying antioxidant systems that will provide a genuine benefit in reducing ageing.
Cellular Responses to Oxidative Damage: Cell Aging. The aim of this project is to identify the mechanisms by which oxidative stress and free radical damage cause cell aging. This work will make a significant contribution to our understanding of the aging process in cells by identifying the major reactive oxygen species that contribute to cell aging, which defence systems and antioxidants provide the greatest degree of protection, what damage accumulates as cells age and which genetic systems ar ....Cellular Responses to Oxidative Damage: Cell Aging. The aim of this project is to identify the mechanisms by which oxidative stress and free radical damage cause cell aging. This work will make a significant contribution to our understanding of the aging process in cells by identifying the major reactive oxygen species that contribute to cell aging, which defence systems and antioxidants provide the greatest degree of protection, what damage accumulates as cells age and which genetic systems are activated as during the process.Read moreRead less
CesA (cellulose synthase) genes of Arabidopsis; all doing the same job or specialists cooperating to make the most abundant biopolymer. The biosphere makes more cellulose than any other polymer with fibre industries depending on its physical properties and atmospheric carbon dioxide levels depending on its stability as a carbon sink. Demonstrations that cellulose production needs CesA genes drove recent progress in elucidating the mechanism of synthesis. CesA proteins all look very similar but i ....CesA (cellulose synthase) genes of Arabidopsis; all doing the same job or specialists cooperating to make the most abundant biopolymer. The biosphere makes more cellulose than any other polymer with fibre industries depending on its physical properties and atmospheric carbon dioxide levels depending on its stability as a carbon sink. Demonstrations that cellulose production needs CesA genes drove recent progress in elucidating the mechanism of synthesis. CesA proteins all look very similar but if all do the same job, why do plants need so many and why do none seem redundant? We will make gene interchanges in transgenic plants, build chimeric genes and identify where each CesA protein operates. This will identify their individual and cooperative contributions to cellulose production.Read moreRead less
Function of a new splicing factor, RBM4. New genomic knowledge is revolutionizing our world. However our understanding of the basic mechanisms of RNA maturation, especially regulation of splicing lags significantly behind our understanding of related genomic processes. This project is a genetic approach to help elucidate the function of new splicing factors and characterize the way in which specific RNA sequences are recognized. It should promote the better understanding of regulatory events inv ....Function of a new splicing factor, RBM4. New genomic knowledge is revolutionizing our world. However our understanding of the basic mechanisms of RNA maturation, especially regulation of splicing lags significantly behind our understanding of related genomic processes. This project is a genetic approach to help elucidate the function of new splicing factors and characterize the way in which specific RNA sequences are recognized. It should promote the better understanding of regulatory events involved in controlling gene expression during development and differentiation. Results from this project will also provide new insights into the 'multifunctionality' of cellular proteins and will illustrate the importance of RNA studies in molecular medicine.Read moreRead less
Genetic analysis of cohesin function and regulation in Drosophila. In yeast, a multiprotein complex, called cohesin, holds newly replicated chromatids together until the cell is ready to partition each chromatid into its daughter cells. We and others have shown that cohesins are regulated differently in animal cells. We propose to combine classical genetic analyses with two new and innovative techniques, time-lapse confocal microscopy of fluorescent proteins in living cells and gene-specific kno ....Genetic analysis of cohesin function and regulation in Drosophila. In yeast, a multiprotein complex, called cohesin, holds newly replicated chromatids together until the cell is ready to partition each chromatid into its daughter cells. We and others have shown that cohesins are regulated differently in animal cells. We propose to combine classical genetic analyses with two new and innovative techniques, time-lapse confocal microscopy of fluorescent proteins in living cells and gene-specific knockout techniques to study key cohesin regulators in Drosophila. These studies will provide us with novel insights into how multicellular organisms regulate the structure and stability of their chromosomes.Read moreRead less