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
Regulation And Role Of Transcription At The Centromere.
Funder
National Health and Medical Research Council
Funding Amount
$737,801.00
Summary
Every human cell has 46 chromosomes. Chromosomes are structures that carry genes in all our cells. The centromere is an essential component of a chromosome. It controls the process of cell division, and it ensures the equal division of the duplicated chromosomes. Defects in centromere function can result in various genetic diseases and development of cancers. The structure of the centromere is unique and its properties are determined by an array of proteins and other as yet unknown factors that ....Every human cell has 46 chromosomes. Chromosomes are structures that carry genes in all our cells. The centromere is an essential component of a chromosome. It controls the process of cell division, and it ensures the equal division of the duplicated chromosomes. Defects in centromere function can result in various genetic diseases and development of cancers. The structure of the centromere is unique and its properties are determined by an array of proteins and other as yet unknown factors that bind to it. In our preliminary work, we have demonstrated that a novel non-protein component in the form of RNA (which are expressed products of genes) is essential for the binding of key proteins to the centromere. The presence and importance of such an RNA component has not been previously suspected and represents an exciting new mechanism that help to determine the functional and structural integrity of the centromere. In this project, we propose to study the details of this RNA and to define how this RNA-related mechanism operates to ensure the proper assembly and function of the centromere during cell division.Read moreRead less
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 Target Genes For Novel Anti-epileptic Therapies In The Mouse
Funder
National Health and Medical Research Council
Funding Amount
$469,802.00
Summary
Epilepsy is a disease which affects 2-4% of the population. There are a wide range of drugs available to treat the condition but there is consistently 30-40% of patients who do not respond well to any of these drugs and who continue to have seizures. The reason that there are no drugs available for these people is that most of the drugs available have been designed along the same principles. A new set of principles is needed to develop new drugs which will be able to treat those people not respo ....Epilepsy is a disease which affects 2-4% of the population. There are a wide range of drugs available to treat the condition but there is consistently 30-40% of patients who do not respond well to any of these drugs and who continue to have seizures. The reason that there are no drugs available for these people is that most of the drugs available have been designed along the same principles. A new set of principles is needed to develop new drugs which will be able to treat those people not responding to current therapy. This project is designed to identify new biologic pathways which may be interrupted with drugs to prevent seizures in people with epilepsy. This project uses a procedure to induce mutations into genes in mice and then screens for mice which do not seize when challenged with a drug which generates seizures in mice. Genetic studies will identify the mutated genes and these will be used as potential targets for new therapies or will identify new biological pathway which should expand the use of future anti-epileptic drugs.Read moreRead less
Molecular Genetics Of The Host Response Defect In Cystic Fibrosis
Funder
National Health and Medical Research Council
Funding Amount
$564,690.00
Summary
Cystic fibrosis is the most common lethal genetic disease in Caucasian populations. Affected individuals suffer from a number of symptoms but the most serious is a chronic infect with the bacterial pathogen Pseudomonas aeruginosa. The sustained lung inflammation caused by infection with Pseudomonas aeruginosa ultimately destroys the structure of the lung to the point where it can no longer function. Gene therapy has been suggested as a possible treatment for the disease but another approach is t ....Cystic fibrosis is the most common lethal genetic disease in Caucasian populations. Affected individuals suffer from a number of symptoms but the most serious is a chronic infect with the bacterial pathogen Pseudomonas aeruginosa. The sustained lung inflammation caused by infection with Pseudomonas aeruginosa ultimately destroys the structure of the lung to the point where it can no longer function. Gene therapy has been suggested as a possible treatment for the disease but another approach is to identify the CF specific aspects of the inflammatory response and target those for therapeutic development. In our previous work we have identified several strong candidates for the inflammatory molecules in the CF lung and in this application we will test those candidates to see whether they play a major role in CF lung disease.Read moreRead less
Microarray-targeted Candidate Gene Approach To Finding Ovarian Cancer Susceptibility Genes
Funder
National Health and Medical Research Council
Funding Amount
$612,933.00
Summary
We propose that subtle, heritable changes in the expression or function of genes that are switched off, or on, early in the development of ovarian tumours, may predispose the individual to ovarian cancer. We will are carry out a large study of the most common subtype of ovarian adenocarcinoma, serous invasive tumors, in order to identify genes that affect a woman's risk of ovarian cancer. Identification of women at elevated risk for ovarian cancer on the basis of their genotype will allow them t ....We propose that subtle, heritable changes in the expression or function of genes that are switched off, or on, early in the development of ovarian tumours, may predispose the individual to ovarian cancer. We will are carry out a large study of the most common subtype of ovarian adenocarcinoma, serous invasive tumors, in order to identify genes that affect a woman's risk of ovarian cancer. Identification of women at elevated risk for ovarian cancer on the basis of their genotype will allow them to be targeted for screening, and for intervention studies, as well as providing fundamental insight into the etiology of ovarian cancer.Read moreRead less
Detection Of Alternative Lengthening Of Telomeres In The Mouse
Funder
National Health and Medical Research Council
Funding Amount
$471,000.00
Summary
In each cell, DNA is packaged into units called chromosomes, the ends of which (i.e., telomeres) become slightly shorter every time they are replicated during the production of new cells. Continued cell replication and hence continued telomere shortening eventually results in the inability of cells to replicate themselves any further. Normal cells have mechanisms to slow down, but not completely prevent telomere shortening. The development of a cancer depends on its cells being able to replicate ....In each cell, DNA is packaged into units called chromosomes, the ends of which (i.e., telomeres) become slightly shorter every time they are replicated during the production of new cells. Continued cell replication and hence continued telomere shortening eventually results in the inability of cells to replicate themselves any further. Normal cells have mechanisms to slow down, but not completely prevent telomere shortening. The development of a cancer depends on its cells being able to replicate themselves many times, and therefore they need to find a method to prevent their telomeres shortening. We discovered one such method, called Alternative Lengthening of Telomeres (ALT), that is used by some cancers. It has been shown in principle that cancer cells can be killed by disrupting their ability to prevent telomere shortening. Therefore, in another project we are developing methods needed to find drugs that inhibit ALT. In the meantime, we have found the first evidence that some normal cells have an ALT-like mechanism. Our speculation is that cancer cells are able to dysregulate and subvert this normal mechanism in order to prevent their telomeres from shortening. In this project, we will analyse the ALT-like mechanism in mice, to determine its characteristics, and to determine what tissues use it. This information will provide critically important insights into the ALT mechanism itself, and the likely side effects of drugs that inhibit ALT.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
Bipolar affective disorder (BP), or manic-depressive illness, is a major cause of disability and mortality worldwide. It has a lifetime prevalence of about 1% and suicide risk of about 20%. The disorder is characterised by episodes of mania or hypomania and depression, appearing in varying succession, with or without intermission. Twin, family, and adoptive studies point to a strong genetic component leading to the development of bipolar disorder, with a heritability of the order of 80%. Yet the ....Bipolar affective disorder (BP), or manic-depressive illness, is a major cause of disability and mortality worldwide. It has a lifetime prevalence of about 1% and suicide risk of about 20%. The disorder is characterised by episodes of mania or hypomania and depression, appearing in varying succession, with or without intermission. Twin, family, and adoptive studies point to a strong genetic component leading to the development of bipolar disorder, with a heritability of the order of 80%. Yet the identification of the genetic basis of the disease has proved exceedingly difficult, with numerous studies producing no definitive data. The lack of convincing results has been interpreted as an indication of complex genetic mechanisms and underlying differences between affected families and ethnic groups. Genetically isolated populations, where most individuals descend from a small number of founders, are believed to hold great potential for understanding the genetic basis of complex diseases, such as bipolar disorder. Affected subjects in such populations are likely to share the same predisposing genes, making these genes easier to identify. During the last 10 years, we have been involved in the study of bipolar disorder in one such population, with very promising results. In this project, we propose to take the research further by collecting more affected families, confirming the current positive findings and narrowing down the search to a small region, possibly a single gene. If successful, the study will be a major breakthrough which, by identifying a molecular pathway and disease mechanism, will contribute valuable and generally valid information on the biological basis of mood disorders.Read moreRead less
Fine Mapping Of A Significant Linkage Region For Endometriosis
Funder
National Health and Medical Research Council
Funding Amount
$518,250.00
Summary
Endometriosis is a common disorder affecting up to 10% of women. In this condition, a special type of tissue that normally lines the inside of the womb (the 'endometrium') starts to grow outside the womb, mostly in the pelvis (lower abdomen). Common symptoms are severe pelvic pain, menstrual problems and infertility. The disease has a major impact on women's health, relationships, productivity and life choices. The mechanisms that cause endometriosis are not well understood. Genetic factors infl ....Endometriosis is a common disorder affecting up to 10% of women. In this condition, a special type of tissue that normally lines the inside of the womb (the 'endometrium') starts to grow outside the womb, mostly in the pelvis (lower abdomen). Common symptoms are severe pelvic pain, menstrual problems and infertility. The disease has a major impact on women's health, relationships, productivity and life choices. The mechanisms that cause endometriosis are not well understood. Genetic factors influence a woman's risk of developing endometriosis and finding genes and pathways leading to this disease would be a major advance. This will help design better approaches for the diagnosis, prevention and treatment of endometriosis. Since 1996, nearly 4,000 women with endometriosis plus their families have joined our genetic study. This includes around 1,000 families with two or more sisters who both have the disease. We have looked at the DNA from these sisters and found significant evidence for a gene or genes affecting endometriosis on one chromosome. No one else has linked this location with endometriosis. We are now focusing our efforts in the laboratory on this area, which contains approximately 250 genes. The aim of our new project is to study genes in the region in more detail to pinpoint the gene or genes responsible for risk of endometriosis.Read moreRead less