Genetic Variation Of Mitochondrial Complex I: Its Role In Rare And Common Diseases
Funder
National Health and Medical Research Council
Funding Amount
$628,415.00
Summary
Our bodies convert food into energy in tiny cellular power plants called mitochondria. Each year about 50 Australian children inherit disorders of mitochondrial energy generation. The most severe disorders cause infant death, while others cause degenerative diseases in later life, particularly affecting brain and muscle. In most cases we lack effective treatments. The genetic causes of mitochondrial disorders are incredibly diverse, with over 70 disease genes known. Some are located on the uniqu ....Our bodies convert food into energy in tiny cellular power plants called mitochondria. Each year about 50 Australian children inherit disorders of mitochondrial energy generation. The most severe disorders cause infant death, while others cause degenerative diseases in later life, particularly affecting brain and muscle. In most cases we lack effective treatments. The genetic causes of mitochondrial disorders are incredibly diverse, with over 70 disease genes known. Some are located on the unique mitochondrial DNA we inherit only from our mothers. Many more genes await discovery. This grant focuses on the most common energy generation disorder, known as Complex I deficiency. Complex I requires 46 separate components to be assembled together in order to work properly, but mutations in the 46 genes encoding these components only seem to explain disease in about half of all patients. Our aim is to identify new disease genes and to determine whether some patients have mutations in two different genes that interact to cause disease, rather than in a single gene. We will use a number of methods to pinpoint where in the genome the causative genes are located and then home in on the exact changes in the genes that cause disease. Identifying these genes will allow us to improve future diagnosis and prevention of mitochondrial disease. We will also generate mice in which one of the Complex I genes has been knocked out. These mice will allow us to better understand the basic disease mechanisms that link gene changes to disease. Understanding the basic biology may allow us to develop new methods of treatment. The mouse models will also be useful for trialling new treatments and for investigating the role of milder mitochondrial problems in common diseases such as diabetes and Parkinson disease. Any new treatments could potentially have wide application.Read moreRead less
Identifying Novel Genes Causing Cytochrome C Oxidase (COX) Deficiency
Funder
National Health and Medical Research Council
Funding Amount
$426,917.00
Summary
Our bodies convert food into energy in tiny cellular power plants called mitochondria. Each year about 50 Australian children inherit disorders of mitochondrial energy generation. The most severe disorders cause infant death, while others cause degenerative diseases in later life, particularly affecting brain and muscle. In most cases we lack effective treatments. The genetic causes of mitochondrial disorders are incredibly diverse, with over 70 disease genes known. Some are located on the uniqu ....Our bodies convert food into energy in tiny cellular power plants called mitochondria. Each year about 50 Australian children inherit disorders of mitochondrial energy generation. The most severe disorders cause infant death, while others cause degenerative diseases in later life, particularly affecting brain and muscle. In most cases we lack effective treatments. The genetic causes of mitochondrial disorders are incredibly diverse, with over 70 disease genes known. Some are located on the unique mitochondrial DNA we inherit only from our mothers. Many more genes await discovery. This study focuses on the mitochondrial disorder cytochrome c oxidase (COX) deficiency, for which we have diagnosed 80 Australian patients. COX requires 13 separate components to be assembled together in order to work properly, but mutations in the genes encoding these components are not present in most patients. We believe that the most common problems will be in genes involved in assembling the components rather than in the components themselves. We will use a number of methods to pinpoint where in the genome the disease genes are located. A key to our strategy is identifying patients likely to have mutations in the same gene. We have identified two such groups, and will do studies that involving fusing two cell lines together to confirm they have the same disorder. We will then perform genetic mapping to look for regions of similarity in the genome using DNA (SNP) chips. We will test how well the genes in such regions are expressed, whether we can correct the problem in cultured skin cells by introducing a healthy copy of that chromosome, and look for gene mutations. Identifying these genes will allow us to improve future diagnosis and prevention and may allow us to develop new methods of treatment. Milder mitochondrial problems also contribute to a range of more common diseases such as diabetes and Alzheimer disease, so any new treatments could potentially have wide applicationRead moreRead less
I am a scientist aiming to improve health outcomes by facilitating the collection and unification of data on human genetic variation together with its clinical impact on human health.
Senataxin, A Novel Protein Involved In The DNA Damage Response
Funder
National Health and Medical Research Council
Funding Amount
$500,460.00
Summary
The human genome is constantly exposed to agents-chemicals that cause DNA damage. Some of these are generated during normal metabolism and are referred to as reactive oxygen species while others comprise damaging sunlight, radiation and a variety of chemical agents. These agents can lead to cancer and a range of pathologies to different tissues including deterioration of brain function. This project is designed to investigate these processes using a specific genetic disorder as a model system. T ....The human genome is constantly exposed to agents-chemicals that cause DNA damage. Some of these are generated during normal metabolism and are referred to as reactive oxygen species while others comprise damaging sunlight, radiation and a variety of chemical agents. These agents can lead to cancer and a range of pathologies to different tissues including deterioration of brain function. This project is designed to investigate these processes using a specific genetic disorder as a model system. This disorder is called ataxia with oculomotor apraxia type 2 or AOA2. This condition develops in the teenage to early twenties and as the name suggests is characterised by loss of control of gait together with difficulties of eye movement. It is due to reduced function of a particular region of the brain called the cerebellum responsible for controlling movement. We have initial data suggesting that cells from these patients are very sensitive to environmental chemicals and their capacity to carry out repair of damage to DNA is compromised. We will investigate the nature of the defect at the molecular level and establish the function of the protein defective in this syndrome. This information will be important to determining specific therapies for AOA2 patients and may also have relevance to other neurodegenerative disorders.Read moreRead less
Functions Of A Novel Conserved DNA Damage Response Protein Family In Telomere Stability
Funder
National Health and Medical Research Council
Funding Amount
$282,825.00
Summary
The free DNA ends of chromosomes, termed telomeres, generally resemble broken DNA. Because broken DNA is a major contributing factor to the onset of cancer, cells try to fix broken ends. However, in case of telomeres, such repair processes have to be prevented because otherwise different chromosomes would fuse with each other. Fused chromosomes are very fragile and cannot be evenly distributed between dividing cells, and are therefore another important trigger of cancer development. Therefore, c ....The free DNA ends of chromosomes, termed telomeres, generally resemble broken DNA. Because broken DNA is a major contributing factor to the onset of cancer, cells try to fix broken ends. However, in case of telomeres, such repair processes have to be prevented because otherwise different chromosomes would fuse with each other. Fused chromosomes are very fragile and cannot be evenly distributed between dividing cells, and are therefore another important trigger of cancer development. Therefore, chromosome ends are covered by a cap, which hides them from the DNA damage response machinery. From these considerations it is clear that there are close connections between the cellular DNA damage response and chromosome ends. Moreover, recently it has become clear that DNA damage proteins are also required to stop normal cells from growing, a process termed senescence. Senescence is a consequence of shortened chromosome ends, and does not occur in cancer cells. Altogether, it is clear that DNA breaks and senescence are two of the major questions for our understanding of cancer development. We have identified a novel conserved protein family that is involved in the response to DNA damage in yeast and humans. In addition, the yeast Mdt1 protein is a very sensitive indicator of changes in the telomere cap. Absence of proteins that organise the cap leads to the addition of several phosphate groups to the Mdt1 protein. We propose that phosphate-coupled Mdt1 prevents chromosome ends from fusion with each other, or from fusing with broken DNA ends after widespread damage. As a consequence, cells that have mild cap defects die at an >1000-fold increased rate in response to DNA damage when they also lack Mdt1. As part of this application we want to find out the precise mechanism by which Mdt1 stabilises chromosome ends, and test our hypothesis that the corresponding human protein termed ASCIZ also has similar functions in protecting chromosome ends.Read moreRead less