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
Defining The Genetic And Environmental Factors That Cause Abnormal Vertebral Segmentation During Embryogenesis
Funder
National Health and Medical Research Council
Funding Amount
$724,147.00
Summary
Many birth defects cause vertebral malformations along the spinal column. They originate as the fetus forms, and may be caused by gene mutation or environmental factors. Whilst studying one type of vertebral malformation we have found a genetic cause for 30% of cases. We will investigate the genetic and environmental cause of the remainder. We will look for new genes causing this disease, and use a mouse model to learn how low oxygen levels during pregnancy causes such malformations
Changes To The Structure Of The Centromere During Differentiation And Cancer Progression
Funder
National Health and Medical Research Council
Funding Amount
$511,294.00
Summary
Every human has 46 chromosomes. Chromosomes are structures that carry genes in all our cells. The centromere is an essential component of a chromosome which governs the process of cell division and segregation of chromosomes. Defects in centromere function cause defects in cell division, which in turn are the cause of various genetic diseases including cancer. We propose to investigate the structure of the centromere and the way in which it changes during cellular differentiation and cancer.
Genetic Basis Of Sudden Cardiac Death In The Young
Funder
National Health and Medical Research Council
Funding Amount
$574,500.00
Summary
Sudden cardiac death is a devastating complication of a variety of cardiovascular disorders. In the young, sudden cardiac death can be caused by both structural abnormalities of the heart, e.g. cardiomyopathies, and electrical abnormalities of the heart, such as familial long QT syndrome. In most young sudden cardiac deaths, these cardiovascular disorders are caused by underlying gene abnormalities which place individuals at a higher risk of sudden death. The aim of this project is to understand ....Sudden cardiac death is a devastating complication of a variety of cardiovascular disorders. In the young, sudden cardiac death can be caused by both structural abnormalities of the heart, e.g. cardiomyopathies, and electrical abnormalities of the heart, such as familial long QT syndrome. In most young sudden cardiac deaths, these cardiovascular disorders are caused by underlying gene abnormalities which place individuals at a higher risk of sudden death. The aim of this project is to understanding the genetic basis of sudden cardiac deaths in the young. In particular, the study will identify and characterise the specific genes which cause sudden cardiac death, and what the underlying mechanism is regarding how a single gene defect can lead to such a devastating clinical outcome. Understanding the various cardiovascular diseases that cause sudden death, clinically screening at-risk individuals, coupled with the initiation of appropriate therapeutic and preventative strategies such as implantation of cardioverter defibrillators will most likely reduce the incidence of sudden cardiac death in the young of our community. Elucidation of the underlying genetic defects which cause many of these cardiac disorders will substantially improve diagnostic accuracy, will be invaluable for genetically screening at-risk individuals and by making the diagnosis earlier in life, will create a larger therapeutic window to allow initiation of therapies to prevent complications of disease, including sudden death.Read moreRead less
I am an epidemiologist using high quality data collections and novel methods to generate new knowledge that will help reduce the impact or prevalence of birth defects and related disability.
Modelling The Loss Of NF1 Heterozygosity In Congenital Pseudarthrosis Of The Tibia (CPT).
Funder
National Health and Medical Research Council
Funding Amount
$482,978.00
Summary
Congenital pseudarthrosis of the tibia or CPT is a dibilitating orthopaedic condition that affects children. Healing of a CPT is poor and, even with modern surgical techniques, amputation is a frequent outcome. As a group experienced in animal models of bone healing, we are well positioned to develop advanced genetic models of CPT in mice. With a better understanding of the underlying processes in CPT we will be able to develop treatments for this severe childhood condition.
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 GRHL-3, A Mammalian Homologue Of Drosophila Grainyhead, In Neural Tube Development
Funder
National Health and Medical Research Council
Funding Amount
$496,500.00
Summary
Spina bifida and anencephaly are two common human congenital malformations that form part of a wide spectrum of mutations known collectively as neural tube defects (NTDs). Patients with the most severe form of spina bifida have a failure of the vertebral column and skin to close over the spinal cord and therefore suffer from limb paralysis and marked bladder and bowel dysfunction. Infants with anencephaly have an open cranial vault and failure of normal brain development and die within the first ....Spina bifida and anencephaly are two common human congenital malformations that form part of a wide spectrum of mutations known collectively as neural tube defects (NTDs). Patients with the most severe form of spina bifida have a failure of the vertebral column and skin to close over the spinal cord and therefore suffer from limb paralysis and marked bladder and bowel dysfunction. Infants with anencephaly have an open cranial vault and failure of normal brain development and die within the first few hours of life. These abnormalities occur frequently (1-1000 live births) and are a direct result of failure of the neural tube to close during embryogenesis. NTDs are influenced by both environmental and genetic factors. The best characterised environmental factor is the dietary supplement folate, which when administered before conception results in a reduction in the incidence of spina bifida. The genetic complexity is evidenced by the array of mouse genetic mutations that give rise to NTDs. One of these mouse mutations, known as Curly tail (ct), has served as the major animal model of human NTDs. This is because the ct mice are resistant to folate administration (like most of the cases of spina bifida currently seen in patients) and because the mice seem to have normal development in virtually all other organ systems. Ironically, the genetic mutation that causes the curly tail phenotype has remained undiscovered for over 50 years. We have now identified the gene mutated in the curly tail mice. This gene is highly conserved in humans suggesting that it will play a similar role in neural tube development in man. The gene, known as GRHL-3, is a descendant of a fly gene critical for development of the nervous system in that organism. The studies we propose here will examine the developmental pathways involved in normal neural tube closure in mice and humans and will impact on our understanding of these devastating congenital malformations.Read moreRead less
THE ROLE OF NOVEL TUMOUR SUPPRESSORS DURING DEVELOPMENT
Funder
National Health and Medical Research Council
Funding Amount
$200,880.00
Summary
Cancer is a disease that is likely to affect 1-4 people at some point in their lifetime. Therefore, understanding what causes cancer is of major importance to medical science. Cancers arise through the accumulation of mutations that alter normal cell proliferation control, differentiation or apoptosis (programed cell death). Many genes involved in cancer have been identified, however, there are likely to be many more genes, that when disrupted or misexpressed can lead to cancer. We are intereste ....Cancer is a disease that is likely to affect 1-4 people at some point in their lifetime. Therefore, understanding what causes cancer is of major importance to medical science. Cancers arise through the accumulation of mutations that alter normal cell proliferation control, differentiation or apoptosis (programed cell death). Many genes involved in cancer have been identified, however, there are likely to be many more genes, that when disrupted or misexpressed can lead to cancer. We are interested in the regulation of cell proliferation, and have been studying this in the genetically amenable animal model system, Drosophila. Central to the control of cell proliferation in all organisms are the Cyclin dependent protein kinases. Cyclin E-dependent protein kinase is required to drive cells from the G1 (resting state) into S phase (where DNA replication occurs). Correct control of Cyclin E is important in limiting cell proliferation and many cancer causing mutations result in up-regulation of this critical cell cycle regulator and premature entry into the cell cycle. We have used a genetic approach using a weak mutation in Drosophila Cyclin E to isolate mutations in other important regulators of the G1 to S phase transition. We have identified a number of genes that act to negatively regulate the cell cycle, 2 of which have characteristics typical of tumour suppressors. We have identified candidate genes for 3 of these mutations, all of which encode novel proteins related to mammalian proteins involved in negative regulation of cell proliferation or tumour suppressors. In this proposal we seek to determine the way in which these proteins function to control cell proliferation in Drosophila. Due to the remarkable conservation of genes involved in cell proliferation control through evolution, this study is likely to be highly relevant to the control of cell proliferation and the development of cancer in humans.Read moreRead less