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
Investigation Of Delta3 Function And Notch Signalling During Cell Fate Specification In Mouse And Human
Funder
National Health and Medical Research Council
Funding Amount
$221,717.00
Summary
This project seeks to understand how cells within the developing embryo are produced and how they are given a specific identity. These processes often require the cell to make a decision about what type of cell it will become. We are using the Delta3 gene, which is present in humans and in the mouse, as a tool for our investigations. Delta3 is expressed at the surface of the cell and Notch (its receptor) is present on the surface of neighbouring cells. Delta3 on one cell will bind to Notch on th ....This project seeks to understand how cells within the developing embryo are produced and how they are given a specific identity. These processes often require the cell to make a decision about what type of cell it will become. We are using the Delta3 gene, which is present in humans and in the mouse, as a tool for our investigations. Delta3 is expressed at the surface of the cell and Notch (its receptor) is present on the surface of neighbouring cells. Delta3 on one cell will bind to Notch on the neighbouring cell and activates Notch. When Notch is activated in a cell it pushes the cell to make its decision. This project aims to determine what exactly is the function of Delta3 in mammals and how at the level of the individual cell this protein exerts its effects. We have generated a mouse in which the Delta3 gene is no longer active and have observed that embryos do not develop normally. We will explore these defects (which affect the skeleton and the brain) in detail in order to define their origins. We will also use these abnormal mice to identify genes, which require the function of Delta3 for their normal activity. It is not only important to define the function of Delta3 in mammals but also to determine this protein functions. We wish to know how exactly Delta3 interacts with Notch. That is, which part of the Delta3 protein binds to which part of the Notch protein. We can address this by modifying the Delta3 protein in small (but revealing ways) and see if it can still bind the Notch receptor in a cell culture assay. Our studies have relevance to humans because recently it has been shown that Delta and Notch are associated with a human syndrome (spondylocostal dysostosis) in which individuals suffer from abnormal skeletons.Read moreRead less
Molecular And Clinico-pathological Investigation Of Congenital Myopathies
Funder
National Health and Medical Research Council
Funding Amount
$743,290.00
Summary
Congenital myopathies are inherited disorders causing muscle weakness from birth. Some types lead to early death of the affected child, while others are compatible with life to adulthood. Like any disease of childhood, the congenital myopathies cause considerable trauma to the families concerned. Couples at risk of having another affected child frequently wait for prenatal diagnosis to become available for their particular disease before attempting to have further children. However, prenatal dia ....Congenital myopathies are inherited disorders causing muscle weakness from birth. Some types lead to early death of the affected child, while others are compatible with life to adulthood. Like any disease of childhood, the congenital myopathies cause considerable trauma to the families concerned. Couples at risk of having another affected child frequently wait for prenatal diagnosis to become available for their particular disease before attempting to have further children. However, prenatal diagnosis is only possible once the gene causing a disorder and the mutation in an individual family are identified. In the past, the Laboratories collaborating in this project, the Molecular Neurogenetics Laboratory, Australian Neuromuscular Research Institute, Perth, and the Neurogenetics Research Unit, New Children s Hospital, Sydney, have identified disease genes for congenital myopathies. Prenatal diagnosis is now possible for families whose disease-causing mutation is identified. However the genetic cause of many of the congenital myopathies remains unknown. DNA and other samples have been sent to the Laboratories from around the world, making us reference centres for congenital myopathy research. Part one of the project is to study these and Australasian samples, to identify other congenital myopathy genes. This will help families who currently cannot have prenatal diagnosis. Finding the genes also increases understanding of the diseases by clarifying which proteins are involved. In part two of the project we shall study the mutated proteins, to try to unravel how the gene mutations cause the diseases. The third part of the project is to reevaluate the highly variable muscle pathology in congenital myopathies in cases where the disease gene is now known, in order to investigate genotype-phenotype correlations. Understanding the pathologic basis of the congenital myopathies will ultimately allow us to begin to think rationally about possible treatments.Read moreRead less
Deficiency of the protein dysferlin causes muscular dystrophy, an inherited degenerative disorder of skeletal muscle. Interestingly, muscle disease due to deficiency of dysferlin does not occur until early adulthood. Affected individuals are very active with normal strength until this age and then there is rapid progression of weakness. Many patients lose the ability to walk within a few years of onset. Little is known about the functional role of dysferlin in muscle, how dysferlin deficiency re ....Deficiency of the protein dysferlin causes muscular dystrophy, an inherited degenerative disorder of skeletal muscle. Interestingly, muscle disease due to deficiency of dysferlin does not occur until early adulthood. Affected individuals are very active with normal strength until this age and then there is rapid progression of weakness. Many patients lose the ability to walk within a few years of onset. Little is known about the functional role of dysferlin in muscle, how dysferlin deficiency results in muscular dystrophy, or why dysferlin-deficient muscle is functionally normal prior to the rapid onset of symptoms. Therefore, the goal of this study is to characterize the role of dysferlin in normal and diseased skeletal muscle. We will examine the consequence of dysferlin-deficiency in patient muscle biopsy samples and patient muscle cells in culture. We will assess the role of dysferlin in the fusion and formation of new muscle cells, examine the effect of dysferlin-deficiency on muscle membrane repair, and establish how normal and mutant dysferlin is made, trafficked and degraded within muscle cells. This research will have immediate applications to the diagnosis and counselling of patients with dysferlin-related disease. In addition it will provide valuable information concerning the mechanisms of disease, essential to the development of specific and successful therapies.Read moreRead less