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
Genetic Models Of Cancer Development And Treatment
Funder
National Health and Medical Research Council
Funding Amount
$645,250.00
Summary
We are taking advantage of the powerful genetic tools in fruit flies to study the genetics of cancer. 72% of cancer genes are conserved between humans and fruit flies, making it a particularly suitable system. This project has two main aims: 1- to build tumours in fruit flies in an effort to understand better the individual genetic lesions that contribute to cancer It takes on average 4-7 mutations for a tumour to develop. While many genes associated with cancer have been identified, there are m ....We are taking advantage of the powerful genetic tools in fruit flies to study the genetics of cancer. 72% of cancer genes are conserved between humans and fruit flies, making it a particularly suitable system. This project has two main aims: 1- to build tumours in fruit flies in an effort to understand better the individual genetic lesions that contribute to cancer It takes on average 4-7 mutations for a tumour to develop. While many genes associated with cancer have been identified, there are many more that have not. What is more, it is still not clear precisely what mutations are responsible for a given tumour as tumours contain many genetic lesions most of which are incidental. We have a collection of fruit flies strains that represent various stages of the progress toward cancer development, and we intend to test different genetic combinations of these to determine which combinations result in cancer. 2- to identify a class of genes we have called 'oncogene suppressor genes' which may have the ability to prevent tumours from forming. Recently, it has been discovered that oncogenes may be required for both the INITIATION of tumours and the MAINTENANCE of tumours. This means that suppressing oncogene function may not only prevent tumour formation, but also tumour maintenance - in other words, it may make tumours go away. Thus, oncogene suppressor genes may represent exciting therapeutic targets for the treatment and possibly also prevention of cancer. At this time it is not clear whether oncogenes are generally required for tumour maintenance, or whether this is a property of only one or a few oncogenes. As these experiments are difficult and expensive to conduct in mammalian systems, we have devised simple, rapid tests in fruit flies instead. We plan to use these tests to investigate the effect of 'oncogene suppressor genes' on tumour initiation and maintenance in fruit flies. Ultimately, we believe these genes may represent therapeutic targets.Read moreRead less
Linkage Infrastructure, Equipment And Facilities - Grant ID: LE150100031
Funder
Australian Research Council
Funding Amount
$630,000.00
Summary
PacBio long read sequencer for the Ramaciotti Genomics Consortium of NSW. PacBio long read sequencer for the Ramaciotti Genomics Consortium of New South Wales: This will be one of the first PacBio sequencers for a service facility in Australia. Unlike other next-generation sequencers that have read lengths of 100 to 700 bases, the PacBio long read sequencer generates an average read length of 8,000 bases and a maximum of 20,000 bases. It will be used for research in genomics, metagenomics and tr ....PacBio long read sequencer for the Ramaciotti Genomics Consortium of NSW. PacBio long read sequencer for the Ramaciotti Genomics Consortium of New South Wales: This will be one of the first PacBio sequencers for a service facility in Australia. Unlike other next-generation sequencers that have read lengths of 100 to 700 bases, the PacBio long read sequencer generates an average read length of 8,000 bases and a maximum of 20,000 bases. It will be used for research in genomics, metagenomics and transcriptomics.Read moreRead less
Understanding how cells compact and segregate DNA in vertebrates. How a cell compacts and divides its DNA is still a major unanswered question in biology. This project will determine the way in which a cell compacts its DNA nearly ten thousand fold to allow the faithful and accurate segregation to daughter nuclei.
Cellular determinants of retrotransposition. This project aims to understand the processes that control retrotransposition in a genome. Transposable elements make up more than 50% of human genomes. The accumulation of retrotransposons through millions of years of evolution has shaped the genomes of all eukaryotic organisms, including humans. Researchers have elucidated mechanisms the host uses to defend the genome against insertional mutagenesis by retrotransposons, but the cellular machinery an ....Cellular determinants of retrotransposition. This project aims to understand the processes that control retrotransposition in a genome. Transposable elements make up more than 50% of human genomes. The accumulation of retrotransposons through millions of years of evolution has shaped the genomes of all eukaryotic organisms, including humans. Researchers have elucidated mechanisms the host uses to defend the genome against insertional mutagenesis by retrotransposons, but the cellular machinery and genomic environments needed for retrotransposition are undefined. This project aims to use models to uncover the mechanisms that control retrotransposition. This is expected to reveal more about human origins.Read 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
How does an essential histone variant effect changes in gene expression? The mechanisms that determine how genes are switched on and off in different tissues and at different times are not clearly known. It is well established that gene expression patterns are determined in part by the molecular signals transmitted by variation in the proteins that package eukaryotic DNA. Our aim is to understand new aspects of these mechanisms that revolve around how our DNA is packaged. This foundational knowl ....How does an essential histone variant effect changes in gene expression? The mechanisms that determine how genes are switched on and off in different tissues and at different times are not clearly known. It is well established that gene expression patterns are determined in part by the molecular signals transmitted by variation in the proteins that package eukaryotic DNA. Our aim is to understand new aspects of these mechanisms that revolve around how our DNA is packaged. This foundational knowledge will deepen our understanding of gene regulation in all complex organisms and will inform future efforts to rationally modulate gene expression patterns in agriculture, research and other important areas.Read moreRead less
Regulatory architecture of the trunk-to-tail transition. This project aims to elucidate gene regulatory mechanisms that control how the head-to-tail axis is laid down during embryonic development. The project capitalises on unique pluripotent stem cell resources and cutting-edge genomic technology developed by the team. This project expects to generate new knowledge in the area of developmental biology and gene regulation that is anticipated to have wider application to the understanding of evol ....Regulatory architecture of the trunk-to-tail transition. This project aims to elucidate gene regulatory mechanisms that control how the head-to-tail axis is laid down during embryonic development. The project capitalises on unique pluripotent stem cell resources and cutting-edge genomic technology developed by the team. This project expects to generate new knowledge in the area of developmental biology and gene regulation that is anticipated to have wider application to the understanding of evolutionary mechanisms and ultimately regenerative medicine.Read moreRead less
Genetic control of plant organ growth. Plants organs, such as leaves and petals, have a distinct size and shape reflecting differences in growth. Despite its importance, very little is known about the mechanisms that regulate growth. The objectives of this proposal are a) to test whether organ growth depends on cell-cell signalling and b) to identifying genes that regulate growth, and to characterize their molecular function.