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
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
The control of chromosome division during female meiosis. Mammalian eggs are stored life-long and finally mature in the hours before ovulation. This project examines how the chromosomes in the egg are separated properly so as to produce a mature egg capable of being fertilized by a sperm. Often in eggs chromosome division is imprecisely executed, and this project will help us understand why this occurs.
Marsupial germ cells and genes. Germ cells are the most fascinating cells in the body, since theirs is the unique responsibility for transmitting life from generation to generation. Studies in mice have suggested that position in the embryo determines their origin, but the early embryology of the mouse is so different from that of other mammals that the events need confirming and extending in another species. The simplified embryology of the tammar wallaby makes it ideal for studying one of the ....Marsupial germ cells and genes. Germ cells are the most fascinating cells in the body, since theirs is the unique responsibility for transmitting life from generation to generation. Studies in mice have suggested that position in the embryo determines their origin, but the early embryology of the mouse is so different from that of other mammals that the events need confirming and extending in another species. The simplified embryology of the tammar wallaby makes it ideal for studying one of the most fundamental questions in the whole of biology: what is the basis for the primal distinction between sex and soma?Read moreRead less
How does the unilaminar blastocyst form an embryo? Marsupials are synonymous with Australia and they are scientifically amazing. An understanding how the single-layered marsupial blastocyst cells are directed to form the complex organisation of an embryo would help us understand the biology underlying the developmental potential of all cells. Understanding these processes is not only of great fundamental interest to developmental biology but also for the development of embryonic stem cell lines. ....How does the unilaminar blastocyst form an embryo? Marsupials are synonymous with Australia and they are scientifically amazing. An understanding how the single-layered marsupial blastocyst cells are directed to form the complex organisation of an embryo would help us understand the biology underlying the developmental potential of all cells. Understanding these processes is not only of great fundamental interest to developmental biology but also for the development of embryonic stem cell lines. This research will continue Australia's high profile in reproductive biology using one of our iconic native mammals. A greater understanding of marsupial reproduction will also contribute to management of our threatened marsupial populations.Read moreRead less
Taming the intruders: the domestication of Tigger transposable elements in mammals. It has become apparent that most of the DNA that makes us what we are is actually comprised of the remnants of invading parasitic DNA acquired over time. A continual battle exists between host which tries to silence or remove this DNA, and the parasite that tries to multiply and spread. We are currently investigating an intriguing aspect of this process that involves host genomes 'domesticating' parasitic DNA to ....Taming the intruders: the domestication of Tigger transposable elements in mammals. It has become apparent that most of the DNA that makes us what we are is actually comprised of the remnants of invading parasitic DNA acquired over time. A continual battle exists between host which tries to silence or remove this DNA, and the parasite that tries to multiply and spread. We are currently investigating an intriguing aspect of this process that involves host genomes 'domesticating' parasitic DNA to provide novel functions, thereby facilitating the evolution of specific characteristics within species.Read moreRead less
TraitCapture: Genomic modelling for plant phenomics under environmental stress. This project aims to develop software to integrate new hyper-spectral and 3D growth models of plant phenomics with population genomics to identify heritable developmental traits across varied environments. Genome wide association studies aim to then be used to identify causal genes. Functional structural plant models incorporating genetic variation will be used to predict growth under simulated stress environments. ....TraitCapture: Genomic modelling for plant phenomics under environmental stress. This project aims to develop software to integrate new hyper-spectral and 3D growth models of plant phenomics with population genomics to identify heritable developmental traits across varied environments. Genome wide association studies aim to then be used to identify causal genes. Functional structural plant models incorporating genetic variation will be used to predict growth under simulated stress environments. The research team unites international industry, the Australian Plant Phenomics Facility, and university statistical geneticists. TraitCapture software will use open standards applicable to both controlled and field environments enabling plant breeders to pre-select adaptive traits to increase crop productivity under environmental stress.Read moreRead less
Identification of nuclear reprogramming factors in oocyte cytoplasm. The mature oocyte contains dominant factors that are capable of erasing tissue specific gene expression profiles of somatic cells. These reprogramming factors would be valuable for dedifferentiation of cells and for nuclear transfer in animal cloning. The research involves determination of reprogramming factors present in active cytoplasm following enucleation of the germinal vesicle, blockage of transcription and translation, ....Identification of nuclear reprogramming factors in oocyte cytoplasm. The mature oocyte contains dominant factors that are capable of erasing tissue specific gene expression profiles of somatic cells. These reprogramming factors would be valuable for dedifferentiation of cells and for nuclear transfer in animal cloning. The research involves determination of reprogramming factors present in active cytoplasm following enucleation of the germinal vesicle, blockage of transcription and translation, and timed cultures. The assays will involve maintenance of reprogramming ability and erasure of somatic gene transcription. By subtractive elimination the function of isolated proteins which are involved in reprogramming will be identified for potential recombinant production.Read moreRead less
Understanding Mitotic Telomere Deprotection. This project aims to study telomeres, the DNA and protein structures that protect chromosome ends. During cell division, cells under stress intentionally uncap their telomeres. This project expects to generate new knowledge that challenges the conventional notion of telomeres as static elements, showing instead that telomeres can be dynamic signalling hubs. Expected outcomes of this project include an understanding of the genetic, proteomic, and signa ....Understanding Mitotic Telomere Deprotection. This project aims to study telomeres, the DNA and protein structures that protect chromosome ends. During cell division, cells under stress intentionally uncap their telomeres. This project expects to generate new knowledge that challenges the conventional notion of telomeres as static elements, showing instead that telomeres can be dynamic signalling hubs. Expected outcomes of this project include an understanding of the genetic, proteomic, and signalling pathways involved in this novel phenomenon. This should provide significant benefits to our fundamental understanding of biological processes that protect human genomes and provide a valuable dataset for research on telomere biology, DNA repair, and genome stability.Read moreRead less