Novel Features And Mechanisms Of Congenital Myopathies
Funder
National Health and Medical Research Council
Funding Amount
$464,500.00
Summary
Congenital myopathies are inherited diseases of skeletal muscle that typically present at birth or in early childhood and are characterised by poor muscle tone and muscle weakness. This group of disorders includes nemaline myopathy, central core disease, congenital fiber type disproportion, and myotubular myopathy. All of these disorders are characterised by disorganisation of the sarcomere, the major structure within skeletal muscle cells that is involved in contraction. In addition, the congen ....Congenital myopathies are inherited diseases of skeletal muscle that typically present at birth or in early childhood and are characterised by poor muscle tone and muscle weakness. This group of disorders includes nemaline myopathy, central core disease, congenital fiber type disproportion, and myotubular myopathy. All of these disorders are characterised by disorganisation of the sarcomere, the major structure within skeletal muscle cells that is involved in contraction. In addition, the congenital myopathies have features in common with virtually all muscle diseases such as slow fibre predominance and alterations in contractile force. We are using nemaline myopathy as a representative congenital myopathy to examine features in common amongst the myopathies, characteristic of the congenital myopathies and specific to nemaline myopathy. In nemaline myopathy patients, mutations have been found in five genes that encode proteins of the filamentous systems of the sarcomere. A feature specific to nemaline myopathy is the presence of abnormal structures of the sarcomere called nemaline rods. We have analysed a large number of nemaline myopathy patients that have mutations in the genes that encode the filament proteins alpha-skeletal actin and tropomyosin. In addition, we have generated mouse models for nemaline myopathy and propose to generate an additional one with novel features. Our mouse model has revealed that a feature previously thought exclusive to dystrophies, is also present in nemaline myopathy. The combined analysis of well-characterised patient samples and mouse models will allow us to address longstanding questions about this particular congenital myopathy and myopathies in general. We will determine how rods form and their protein composition. Our mouse models in particular will allow us to address the molecular mechanisms that underpin the increase in slow twitch fibres and the effects that a particular mutation has on muscle function.Read moreRead less
THE ROLES OF CYTOSKELETAL PROTEINS IN SKELETAL MUSCLE FUNCTION AND DISEASE
Funder
National Health and Medical Research Council
Funding Amount
$466,650.00
Summary
Congenital myopathies are inherited diseases of skeletal muscle that typically present at birth or in early chilhood and are characterised by poor muscle tone and muscle weakness. This group of disorders includes nemaline myopathy, central core disease, congenital fiber type disproportion, and myotubular myopathy. All of these disorders are characterised by disorganisation of the sarcomere, the major structure within skeletal muscle cells that is involved in contraction. In nemaline myopathy pat ....Congenital myopathies are inherited diseases of skeletal muscle that typically present at birth or in early chilhood and are characterised by poor muscle tone and muscle weakness. This group of disorders includes nemaline myopathy, central core disease, congenital fiber type disproportion, and myotubular myopathy. All of these disorders are characterised by disorganisation of the sarcomere, the major structure within skeletal muscle cells that is involved in contraction. In nemaline myopathy patients, mutations have been found in five genes that encode proteins of the filamentous systems of the sarcomere. Therefore, the genes for other thin filament, thick filament and Z-line proteins are excellent candidates for these disorders. Research from our lab has identified a novel region of the sarcomere and the genes encoding the proteins present in this region provide additional candidates for the congenital myopathies. We will further characterise the proteins in this novel structure to determine its function and the role that it plays in muscle disease pathologies. In order to study the relationship between disease pathology and muscle weakness in nemaline myopathy, we generated a mouse model by expressing a mutant protein, a-tropomyosin slow, found in human patients in mice. All features of the disease found in humans are present in the mice. A key feature of this disease in mice is the ability for muscle cells to grow in diameter or hypertrophy to offset the muscle weakness. We will use these mice to trial therapies including hypertropy-inducing agents, to prevent and reverse muscle weakness. In addition, we will generate an additional mouse model for this disease with a mutation in a gene encoding another filamentous protein. A comparison of the two models using microarray analysis will help us identify additional genes that are being affected in this disease and to generate a molecular expression profile that will aid in the diagnosis of this disease.Read moreRead less
Identification Of Genes Important In Myeloid And Haemopoietic Development By Genetic Screening In Zebrafish
Funder
National Health and Medical Research Council
Funding Amount
$425,250.00
Summary
Zebrafish have emerged as a powerful experimental model in developmental genetics. Their favourable attributes include their reproductive biology, the optical clarity of embryos, and the accessibility of embryos for experimental procedures. Previous studies overseas have recovered over 1500 strains of zebrafish with inherited diseases due to induced mutations in about 500 genes. Many of these zebrafish have abnormalities of unexpected precision and are leading to new genes with novel specialized ....Zebrafish have emerged as a powerful experimental model in developmental genetics. Their favourable attributes include their reproductive biology, the optical clarity of embryos, and the accessibility of embryos for experimental procedures. Previous studies overseas have recovered over 1500 strains of zebrafish with inherited diseases due to induced mutations in about 500 genes. Many of these zebrafish have abnormalities of unexpected precision and are leading to new genes with novel specialized functions. About 50 mutant zebrafish strains exist in which red blood cell development is perturbed - this was easily recognized because the transparency of embryos enabled lack of blood be easily seen. Our new studies aim primarily to recover mutant zebrafish with disorders of white blood cell formation. We have identified methods to recognize failure of white blood cell formation in zebrafish, and will employ these methods to look for inherited disorders that specifically affect white blood cell development in a process called genetic screening. Fish with different sets of randomly mutated genes will be systematically screened to identify those with abnormal white blood cell development. We have tested our approach and identified several mutants affecting white blood cell development. Once these new strains of fish are identified, we will find the genetic lesion responsible for the abnormality in several of the most interesting strains by gene mapping and positional cloning. Hence, the mutant zebrafish identified in the screen will eventually lead to the discovery of new genes important in white blood cell growth and development. The fish themselves will provide insights into the causes of congenital diseases of white blood cells. Since many genes involved in early development are also important in cancer, we believe that newly identified genes will also help understand the causes of abnormal growth of white blood cells in leukaemia.Read moreRead less
A New BTB-ZF Family Transcription Factor Required In Development And Dysregulated In Malignant Disease
Funder
National Health and Medical Research Council
Funding Amount
$439,813.00
Summary
We are studying the function and biology of a novel gene that looks like a generegulator. We generated a zebrafish mutant with defective myeloid development, and we found this gene causes the defect. This mutant fish provides a handle on the biological function of the gene in development. This gene has the hallmarks of a transcription factor and we will study how it regulates other genes, and how it may be a target for treatment of several cancers in which expression of this gene is activated.
Defining The Genetic Causes Of The Abnormal Vertebral Segmentation Syndrome, Spondylocostal Dysostosis
Funder
National Health and Medical Research Council
Funding Amount
$476,523.00
Summary
There are many birth defects that cause vertebral malformations along the spinal column. These occur as the embryo develops in utero, during the formation of structures known as somites. Somites also form the ribs, muscle, tendons and dermis. We are studying an example of this type of birth defect called spondylocostal dysostosis (SCD). We have shown that mutations in three different genes cause some cases of this inherited disease in humans. These genes are called DLL3, MESP2 and LFNG. However, ....There are many birth defects that cause vertebral malformations along the spinal column. These occur as the embryo develops in utero, during the formation of structures known as somites. Somites also form the ribs, muscle, tendons and dermis. We are studying an example of this type of birth defect called spondylocostal dysostosis (SCD). We have shown that mutations in three different genes cause some cases of this inherited disease in humans. These genes are called DLL3, MESP2 and LFNG. However, 80% of SCD patients do not have a mutation in any of these genes. Thus we need to discover how these other cases occur. This project uses two strategies in parallel. Firstly, we will analyse large families that have a history of SCD, and use this information to find causative gene mutations. However, a significant proportion of cases occur without family history. To find out what genes are involved in these cases is more difficult. We have created a mutant mouse by specifically deleting the DLL3 gene. This mouse has very similar vertebral malformations to SCD. We will compare embryos from normal and mutant mice to find genes that do not operate normally in the mutant. These genes are candidates for causing SCD, and thus we will screen these genes in human patients for mutations. However, simply finding a change in a candidate gene does not necessarily mean that this is the cause of SCD. To prove this, we have developed several tests to determine if the mutation alters the normal function of the protein encoded by the mutated gene. This work will greatly benefit the future genetic assessment of SCD patients. In addition, by studying our mouse model of SCD, we will gain a greater understanding of how DLL3 functions. This knowledge may be useful in developing stem cell-based therapies that involve the production of specific cell types.Read moreRead less
Understanding Human Dysmorphology Through Analysis Of ENU Mutant Mice
Funder
National Health and Medical Research Council
Funding Amount
$602,501.00
Summary
Birth defects are common and have an enormous impact on both the individual and their family. Birth defects are by definition the products of abnormal development of the embryo. Our research is aimed at identifying the normal mechanisms that usually prevail during development and the disturbances to those mechanisms that result in birth defects. These findings will lead to improved diagnostic, therapeutic and preventative options for families affected by birth defects
Rapid Identification And Characterisation Of Genes Involved In Skeletal Development
Funder
National Health and Medical Research Council
Funding Amount
$550,536.00
Summary
Birth defects are common and have an enormous impact on both the individual and their family. Birth defects are by definition the products of abnormal development of the embryo. Our research is aimed at identifying the normal mechanisms that usually prevail during development and the disturbances to those mechanisms that result in birth defects. These findings will lead to improved diagnostic, therapeutic and preventative options for families affected by birth defects
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.
Novel Approach And Insights Into Muscle Stem Cell Transplantation
Funder
National Health and Medical Research Council
Funding Amount
$642,401.00
Summary
The successful use of stem cell therapy absolutely requires the longterm intergration of the therapeutic cells into the target tissue. This application will adapt a chemotherapy-based strategy to drive the successful incorporation and growth of healthy muscle stem cells into diseased muscle. This study will both enhance our understanding of muscle stem cells and provide proof-of-principle for a universal approach to the uptake of stem cells by a target tissue.
Genetic Control Of Body Patterning: Intersection Of Transcriptional And Signalling Activity In Head Formation
Funder
National Health and Medical Research Council
Funding Amount
$579,932.00
Summary
A most critical step in embryonic development is the assembly of the different tissue components into a three-dimensional structure in order to build a major body part of the foetus. The objective of our research is to understand how the mechanisms that control genetic activity and cell-to-cell signalling may cooperate in the formation of the head and face of the embryo. The outcome will focus future clinical investigations to the most relevant genetic determinants of craniofacial defects.