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
Novel Pathways Involving APC And PAR-2 In Cartilage Degradation In Osteoarthritis
Funder
National Health and Medical Research Council
Funding Amount
$448,834.00
Summary
Loss of the cartilage that normally lines the ends of bones is central to joint failure in arthritis and the need for replacement surgery. There are presently no treatments that stop cartilage breakdown in joint disease. This project investigates the role of a new pathway not previously thought to be active in cartilage, in the progressive damage seen in arthritis. Successful completion of these studies may provide a novel new strategy to treat joint disease.
The Effects Of Maternal Health On Fetal Kidney Development And Its Function
Funder
National Health and Medical Research Council
Funding Amount
$297,338.00
Summary
There is an epidemic of renal disease among Australian aborigines. While much of this could have been prevented by effective control of Group A streptococcal skin infections, there is also evidence that the high susceptibility to end-stage renal disease is related to poor intrauterine development of the kidney as low- birth weight is a predisposing factor. Mothers, whose renal function is impaired, tend to have babies which are low birth weight. There is no knowledge about the effects of materna ....There is an epidemic of renal disease among Australian aborigines. While much of this could have been prevented by effective control of Group A streptococcal skin infections, there is also evidence that the high susceptibility to end-stage renal disease is related to poor intrauterine development of the kidney as low- birth weight is a predisposing factor. Mothers, whose renal function is impaired, tend to have babies which are low birth weight. There is no knowledge about the effects of maternal renal dysfunction on development of the fetal kidney. We have recently developed an animal model in which we can study the effects of maternal renal dysfunction on the development of the kidney of her offspring. Human beings form 60% of the functional units (nephrons) in the kidney in the last trimester. Sheep, like human beings (and unlike rats), completely form all the nephrons that they will ever have, during intrauterine life. While the fetal kidneys play an essential role in the formation of amniotic fluid, regulation of fetal fluid and electrolyte homeostasis depends on maternal renal function via transplacental transfer. If maternal renal function is reduced, it is likely that the fetal kidneys will be exposed to a greater volume and solute load through transplacental equilibration. This may have a profund effect on renal development especially if coupled with an inadequate maternal diet and a high maternal salt intake. Under these conditions we predict that development of the fetal kidney will be impaired and renal capacity after birth, reduced. This means that the kidney will 'age' more rapidly. Thus the affected individual would be predisposed to renal disease in adult life. In our animal model we will study the effects and interactions of maternal renal insufficiency, poor fetal nutrition and a high maternal salt intake on fetal kidney development and function.Read moreRead less
Disorders of sexual development are among the most common form of birth defects in humans (1 in 4,000 births) because failure of the gonads to develop does not affect the viability of the individual. Such disorders can have profound psychological and medical consequences upon the individual, family, and society. Some intersexual conditions are the result of inappropriate exposure to hormones during fetal life, and others are due to spontaneous or inherited gene mutation. About 5-10% of ovarian c ....Disorders of sexual development are among the most common form of birth defects in humans (1 in 4,000 births) because failure of the gonads to develop does not affect the viability of the individual. Such disorders can have profound psychological and medical consequences upon the individual, family, and society. Some intersexual conditions are the result of inappropriate exposure to hormones during fetal life, and others are due to spontaneous or inherited gene mutation. About 5-10% of ovarian cancer cases, that affect 1 in 8000 Australian women, are due to the inheritance of a faulty gene. An understanding of the way gene expression and hence tissue differentiation is altered after sex reversal will inform us about the causes and consequences of normal and abnormal sexual development, gonadal malignancies and infertility. The gonad is unusual in that two completely different organs can arise from an essentially identical primordium, so that errors in development lead to intersexual phenotypes. We will use our new experimental animal model to clarify these processes.Read moreRead less
Dissecting The Role Of Hedgehog Signalling In Chondrogenesis And Skeletal Disease
Funder
National Health and Medical Research Council
Funding Amount
$408,739.00
Summary
There are close to 400 inherited disorders that affect how the skeleton develops, as well as a range of injury and age-related skeletal defects. There is much interest in treating such abnormalities with artificial bone grown outside the body. In order to achieve this aim we must understand all of the processes involved in producing and maintaining bone within the body. We are using both mouse and cell culture models of skeletal development to increase our understanding of these processes.
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
THE ROLE OF UBIQUITIN LIGASE ADAPTOR PROTEIN NDFIP1 IN NEURONAL DEVELOPMENT
Funder
National Health and Medical Research Council
Funding Amount
$581,813.00
Summary
Many brain diseases are characterized by faulty connections between nerve cells (neurons), in some cases caused by the inability to remove unwanted proteins from the neuron. This function is carried out by the ubiquitin-proteasome system (UPS). We have evidence that a UPS protein called Ndfip1 is important for forming functional brain circuits. We aim to discover whether neuron growth, branching and connectivity is promoted by Ndfip1 targeting of PTEN (phosphatase with tensin homology) to the UP ....Many brain diseases are characterized by faulty connections between nerve cells (neurons), in some cases caused by the inability to remove unwanted proteins from the neuron. This function is carried out by the ubiquitin-proteasome system (UPS). We have evidence that a UPS protein called Ndfip1 is important for forming functional brain circuits. We aim to discover whether neuron growth, branching and connectivity is promoted by Ndfip1 targeting of PTEN (phosphatase with tensin homology) to the UPS.Read moreRead less
Normal embryonic and foetal devlopment depends on the ability of cells to move from one place to another. This behaviour enables cells to be produced at one site and transported to one or a number of other sites. Although the face appears to us as a single seamless unit it originates as a number of blocks of tissue which begin development separately and must grow in a coordinated way that enables them to meet at precisely the correct time, in the correct place and in the correct order. The basis ....Normal embryonic and foetal devlopment depends on the ability of cells to move from one place to another. This behaviour enables cells to be produced at one site and transported to one or a number of other sites. Although the face appears to us as a single seamless unit it originates as a number of blocks of tissue which begin development separately and must grow in a coordinated way that enables them to meet at precisely the correct time, in the correct place and in the correct order. The basis of this growth and fusion is the ability of individual cells to move around the embryo to supply the raw materials for this construction process when and where they are needed. The combined activities of the cells in constructing the various parts of the embryo is known as morphogenesis which literally means creating shape. We are trying to gain insight into the basis of morphogenesis that produces the face. This is important because the face and other structures that are closely associated with it are particularly prone to errors. Despite this, surprisingly little is known about the mechansims that control development of the face. We know a great deal about which cells are involved in constructing the face but very little about what triggers the initial steps of development or maintains ordered growth. Our research is aimed at defining genes that are important in controlling development of the face through the study of normal development and birth defects. We are defining the function of genes that appear to be important in controlling the behaviour of cells during early development of the face. This knowledge will assist in understanding the control mechanism for facial devlopment and will eventually lead to improvements in the treatment and prevention of birth defects affecting these structures.Read moreRead less
A man's reproductive health and fertility is affected by processes that occur long before adulthood. The testis and sperm precursor cells first form in the fetus and then grow until the time of puberty, when the upper limit for sperm production is set. This project studies how one key signaling molecule, activin, helps establish normal testicular architecture and drives maturation of sperm precursor cells, and how it contributes to aberrent function in men with testicular cancer.
Body Segment Identity Specification By The Transcription Regulator, Moz
Funder
National Health and Medical Research Council
Funding Amount
$366,301.00
Summary
One in 28 newborns have birth defects. Cleft palate and aortic arch defects are among the most common, always requiring surgery and often causing lethality. We propose to study a protein, Moz, which is essential for palate and aortic arch development. Moz (Monocytic leukaemia zinc finger protein) was first identified in human chromosomal abnormalities causing particularly aggressive forms of childhood and adult leukaemia. We have shown previously that Moz is essential for the formation of blood ....One in 28 newborns have birth defects. Cleft palate and aortic arch defects are among the most common, always requiring surgery and often causing lethality. We propose to study a protein, Moz, which is essential for palate and aortic arch development. Moz (Monocytic leukaemia zinc finger protein) was first identified in human chromosomal abnormalities causing particularly aggressive forms of childhood and adult leukaemia. We have shown previously that Moz is essential for the formation of blood stem cells. Moz can regulate the activity of genes, but which genes it regulates in vivo is unknown. In the absence of Moz, mice are born with a cleft palate, lack the thymus, where immune cells are instructed, and fail to form the lung blood circulation, so that they are unable to supply their blood with oxygen after birth. Moz deficiency also causes defects of the vertebrate column, such that individual vertebrae acquire the appearance of their neighbours. These symptoms are typical for a general defect in positional information of individual body segments with respect to their location along the body axis. We will investigate the molecular mechanisms that require Moz in patterning of the body axis. This project will characterize a genetic mechanism that is crucial for normal development of the palate, the aorta and the vertebrate column.Read moreRead less