The Regulation And Function Of Cadherin-mediated Adhesion Within The Zebrafish Myotome.
Funder
National Health and Medical Research Council
Funding Amount
$436,773.00
Summary
Co-ordinating how cells interact with their neighbours and where different cells are positioned within an organ is the role of proteins termed cell adhesion molecules. They delineate and sort cells into different groups depending on which cell adhesion molecules are expressed on their surface. Cell adhesion molecules are also important during the onset of disease, in particular cancer, where the levels and type of cell adhesion molecules expressed on the surface of a cancer cell can determine ho ....Co-ordinating how cells interact with their neighbours and where different cells are positioned within an organ is the role of proteins termed cell adhesion molecules. They delineate and sort cells into different groups depending on which cell adhesion molecules are expressed on their surface. Cell adhesion molecules are also important during the onset of disease, in particular cancer, where the levels and type of cell adhesion molecules expressed on the surface of a cancer cell can determine how invasive or aggressive the cancer cell will become. However, despite the fundamental importance that cell adhesion plays in sorting out cells in every tissue, the exact basis of cell migratory behaviours that occur within the intact organism remain poorly defined. We have examined the ability of specific members of a particular class of cell adhesion molecules, the classical Cadherins, to control formation of muscle. To do this we have examined muscle formation within embryos of the zebrafish, a small embryologically accessible fresh water fish. We have determined how different cadherin molecules co-ordinate the final pattern of the myotome, the structure that gives rise to the majority of muscle in the early embryo. We have determined that differential cell adhesion drives cell sorting of specific muscle cell types via differential use of members of the classical cadherin family of proteins. This study aims to look further at the way that these proteins are regulated in different muscle cells of the forming body. By understanding how these molecules regulate cell sorting and adhesion within the zebrafish myotome we hope to be able to apply this knowledge to how these molecules control the formation of more complex tissues. Furthermore, we believe the implication of specific signalling pathways in the control of cadherin gene expression has particular implications for the role these proteins play in the progression of metastatic cancer.Read moreRead less
Impact Of The Extraembryonic Tissues On Early Embryonic Development: Genetic Basis Of Abnormal Body Plan
Funder
National Health and Medical Research Council
Funding Amount
$316,326.00
Summary
An important milestone of early development is the attachment (or implantation) of the embryo to the wall of the womb through the action of a specialized population of cells known as the trophoblasts. The early conceptus comprises not only cells that make up the embryo but also those (called extraembryonic cells) that later forms the placenta, and the membranes that wrap around the developing fetus. The placenta and the membranes are indispensable for the normal fetal growth by providing the eff ....An important milestone of early development is the attachment (or implantation) of the embryo to the wall of the womb through the action of a specialized population of cells known as the trophoblasts. The early conceptus comprises not only cells that make up the embryo but also those (called extraembryonic cells) that later forms the placenta, and the membranes that wrap around the developing fetus. The placenta and the membranes are indispensable for the normal fetal growth by providing the effective nourishment and protection for the developing fetus. Recent studies in the mouse have revealed that normal development of the recently implanted conceptus depends on the reciprocal interaction of the embryonic and extraembryonic cells. Abnormal embryo may form if the non-embryonic cells do not differentiate normally, as seen in the situation when an X-chromosome is lost from the female embryo (as in 45X0 Turner syndrome) and in early conceptus that carries a gene mutation that affects the production of growth factors by the extraembryonic cells. Functional deficiency of the extraembryonic cells might be a cause for early pregnancy loss where the conceptus has successfully implanted but the embryo fails to form. The remarkable conservation of the molecular mechanism that controls mammalian development allows us to use the mouse embryo as a genetic model for human development. The proposed project is designed to examine in a laboratory mouse model the molecular and cellular factors that regulate the activity of the extraembryonic cells. Specifically, we focus on a gene known as Sox17, which may be involved with the differentiation of the extraembryonic cells. We will study the impact of the mutation of this gene on the development of the early embryo to test the hypothesis that the extraembryonic cells may fulfill an important function in ensuring normal embryo formation, in addition to the other roles of nourishment and mechanical protection of the fetus.Read moreRead less
Reprogramming The Renal Epithelium To Reinitiate Nephrogenesis
Funder
National Health and Medical Research Council
Funding Amount
$636,199.00
Summary
It has been shown that a mature cell type can be reprogrammed to a different type of cell in vivo via the introduction of genes critical during an earlier stage of organ development. In this way, new beta-islet cells in the pancreas can be made. In this study, we will use our understanding of kidney development to redirect the cells of the kidney tubules to dedifferentiate and form new nephrons. This may ultimately result in a regenerative strategy to treat chronic renal disease.
Dissecting The Embryonic Blood-endothelial Regulatory Code And Investigating Its Role In Leukaemia
Funder
National Health and Medical Research Council
Funding Amount
$646,389.00
Summary
Cancer initiating cells acquire stem cell characteristics and multiply within a supportive environment that helps maintain and propagate malignant cells. Identifying the normal hierarchy of gene control within blood stem cells and designing therapies that target cancer cells is the ultimate goal of this body of work.
Periodontal Mesenchymal Stem Cells For Periodontal Regeneration
Funder
National Health and Medical Research Council
Funding Amount
$358,000.00
Summary
Dental diseases affecting the gums (periodontal disease) are extremely prevalent in our society. The effects of periodontal disease can be particularly severe as loss of support for the teeth leads to loose teeth and severely compromised masticatory function. If left untreated, the associated pain and loss of function may necessitate extraction of the teeth. We have recently identified cells residing in the periodontal ligament which may be adult stem cells. This project will further characteriz ....Dental diseases affecting the gums (periodontal disease) are extremely prevalent in our society. The effects of periodontal disease can be particularly severe as loss of support for the teeth leads to loose teeth and severely compromised masticatory function. If left untreated, the associated pain and loss of function may necessitate extraction of the teeth. We have recently identified cells residing in the periodontal ligament which may be adult stem cells. This project will further characterize these cells and explore whether they can be used to restore periodontal tissues damaged by periodontal disease.Read moreRead less
The Role Of Heterochromatin In Regulating Cellular Proliferation And Development
Funder
National Health and Medical Research Council
Funding Amount
$504,000.00
Summary
Fundamental to the development of a multicellular organism is that for each cell type performing a specialised function, a different set of genes are turned on with the remainder being shut off. One of the most significant unanswered questions in biology is how a cell-type specific gene expression profile is established during early development. The answer to this question has important implications in understanding normal and abnormal cellular processes. Gene expression in a cell occurs in the ....Fundamental to the development of a multicellular organism is that for each cell type performing a specialised function, a different set of genes are turned on with the remainder being shut off. One of the most significant unanswered questions in biology is how a cell-type specific gene expression profile is established during early development. The answer to this question has important implications in understanding normal and abnormal cellular processes. Gene expression in a cell occurs in the nucleus where genes are stored. In the nucleus, DNA is not in a free form but is covered with an equivalent weight of protein (histones) to form a structure known as chromatin. It has become clear that the chromatin structure encompassing a gene is the critical factor that determines whether a gene is expressed or silenced. We propose that developmental and cell-type specific mechanisms operate in a cell to assemble genes into highly specialised chromatin structures that permit (euchromatin) or restrict (heterochromatin) gene expression. In other words, the genome of each different cell type is organised into a unique and dynamic chromatin pattern and this pattern determines the gene expression profile. This investigation will show that the critical cellular mechanism that determines the chromatin pattern for a particular cell type is the regulation of the quantity and quality of heterochromatin. Specifically, we will demonstrate that this is achieved, in a developmental and tissue specific manner, by changing the make-up of chromosomal domains through the replacement of histone proteins with specialised forms of histones called variants . In addition, we will expose a new mechanism of how heterochromatin formation controls the rate of cellular proliferation. This information will provide new insights into how gene expression profiles are established at precise times in early development, and offer a new strategy to inhibit the proliferation of cancer cells.Read moreRead less
The Function Of An Essential Histone Variant During Early Development.
Funder
National Health and Medical Research Council
Funding Amount
$436,980.00
Summary
Gene expression in a cell occurs in the nucleus where genes are stored. In the nucleus, DNA is not in a free form but is covered with an equivalent weight of protein to form a structure known as chromatin. Chromatin is a periodic structure made up of repeating, regularly spaced subunits, the subunit being the nucleosome. A nucleosome consists of a group of proteins (histones) wrapped around with DNA. A nucleosome is capable of blocking gene expression therefore one important function of chromati ....Gene expression in a cell occurs in the nucleus where genes are stored. In the nucleus, DNA is not in a free form but is covered with an equivalent weight of protein to form a structure known as chromatin. Chromatin is a periodic structure made up of repeating, regularly spaced subunits, the subunit being the nucleosome. A nucleosome consists of a group of proteins (histones) wrapped around with DNA. A nucleosome is capable of blocking gene expression therefore one important function of chromatin is to prevent unwanted gene expression which is essential to allow an organism to develop properly. When gene expression is not accurately controlled by chromatin developmental defects or cancer could result from the production of incorrect proteins. To control correct gene expression, highly specific mechanisms must operate in the cell to remove, or disrupt, nucleosomes at certain genes at a precise time during development. One mechanism that we believe to be important is changing the make-up of a nucleosome. This can be achieved in the cell by the replacement of histones with different specialised forms of these histones (variants). It is thought that these histone variants could specifically expose certain genes and thereby turn them on. Once the correct protein is made in sufficient amounts the histone variants could be rapidly exchanged for the normal histones to shut off the gene. Employing a new approach, we will study one of these histone variants to discover the role it plays in turning genes on at precise times in early development during the formation of different specialised cell types. This new information may define targets for the prevention of incorrect gene expression during cancer progression or abnormal development.Read moreRead less
Head Development: Genetic Determinants And Tissue Potency
Funder
National Health and Medical Research Council
Funding Amount
$947,116.00
Summary
Congenital malformations involving major defects of brain (anencephalus and related anomalies) and facial structures (ear, face and neck) are encountered in 3.4 and 1.4 per 10000 births respectively (Congenital Malformations Australia 1981-1996, National Perinatal Statistics Unit) and they constitute a substantial clinical burden. It is believed that these major structural defects usually result from abnormal development in the first trimester, which coincides with the time frame for the formati ....Congenital malformations involving major defects of brain (anencephalus and related anomalies) and facial structures (ear, face and neck) are encountered in 3.4 and 1.4 per 10000 births respectively (Congenital Malformations Australia 1981-1996, National Perinatal Statistics Unit) and they constitute a substantial clinical burden. It is believed that these major structural defects usually result from abnormal development in the first trimester, which coincides with the time frame for the formation of the basic components of the embryonic head in the mouse. Knowledge of the formation of the head in the mouse model is therefore relevant to the understanding of related developmental processes in early human development. This project which involves the application of sophisticated embryological and molecular analyses on mouse embryos generated by transgenesis and genetic manipulation provides a detailed studies of craniofacial morphogenesis in a mammalian model for early human development. The micro-manipulation procedures, embryo culture, fluorescence microscopy and the in situ hybridization are routinely performed in our laboratory, and most of the mouse lines are well established in my laboratory. Experiments proposed for this project that focus on the embryological and molecular analysis of normal and mutant embryos should discover new information on the cellular and molecular mechanisms that regulate head development. The knowledge will also offer insight into the pathogenesis of similar craniofacial malformations in other mutant embryos.Read moreRead less