This is a study of the biological system of epigenetics. Every cell in our body has the same genetics, or library of information contained in the form of DNA sequence. Epigenetics is the system that controls how this DNA is used in a particular situation, or what books are opened and read. During embryonic development, cells know what they want to become, e.g., a muscle cell, and, once they take on an identity, remember that they are when they duplicate themselves during growth. Epigenetics does ....This is a study of the biological system of epigenetics. Every cell in our body has the same genetics, or library of information contained in the form of DNA sequence. Epigenetics is the system that controls how this DNA is used in a particular situation, or what books are opened and read. During embryonic development, cells know what they want to become, e.g., a muscle cell, and, once they take on an identity, remember that they are when they duplicate themselves during growth. Epigenetics does not achieve this through changing genetics the library always stays intact. Rather, it acts by using proteins or chemicals to make DNA functional in one way, or another. Genomic imprinting is a special type of epigenetics. While an embryo has received identical genetic information from each of its parents, the epigenetic information received from each parent was not entirely the same. Some genes which behave differently according to what parent they came from. For example, a gene that makes a growth factor protein is active only if received from the father. If received from the mother, it is inactive, and makes no protein. Genes behaving in this way are known as imprinted genes. We are trying to discover what epigenetic mechanisms are behind this behaviour of imprinted genes. One way we are approaching this problem is to study germ cells the cells giving rise to eggs and sperm. These cells are unusual in that their imprinted genes behave in the same way regardless of whether they were received from the mother or father, i.e., like any other gene. If we can understand why this is the case, we will be better able to understand why imprinted genes behave the way they do in the rest of the cells of the body. Broadly, the mechanisms we uncover should further our understanding of germ cell development, gene expression, and disease. Perturbations in the epigenetic profile are likely causes of human disease, including cancer.Read moreRead less
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
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
Molecular Basis Of Transgenerational Epigenetic Inheritance In Mammals
Funder
National Health and Medical Research Council
Funding Amount
$477,965.00
Summary
While it has long been recognised that it is not just DNA, but chromosomes, that are passed from the gametes to the embryo, the non-DNA component was thought to carry no information with respect to the offspring's ultimate phenotype. However, there is now evidence that the non-DNA component, the epigenetic component, can play a role in the inheritance of phenotype in mammals. This study will attempt to determine the molecular nature of this phenomenon.
Retrotransposons As Controlling Elements In Mammals: A Screen For Expression In Somatic Cells And Cancer
Funder
National Health and Medical Research Council
Funding Amount
$452,545.00
Summary
Differences between individual mammals are generally thought to be due to differences either between their genes, or between their environments. However, in many cases genetic or environmental factors cannot account for differences between individuals. We have studied mice in which dramatic differences between genetically identical individuals are due solely to the activity of a type of transposable element (transposon). There are tens of thousands of similar elements in the genomes of all mamma ....Differences between individual mammals are generally thought to be due to differences either between their genes, or between their environments. However, in many cases genetic or environmental factors cannot account for differences between individuals. We have studied mice in which dramatic differences between genetically identical individuals are due solely to the activity of a type of transposable element (transposon). There are tens of thousands of similar elements in the genomes of all mammals. A large body of evidence demonstrates that transposons can disrupt gene expression. To prevent this from occurring, most organisms have evolved mechanisms to keep transposons silent. However, fragmentary evidence indicates that transposons are at least sometimes expressed in normal and cancer cells. We hypothesize that activity of transposons in mammals alters gene expression sufficiently to cause variation between individuals, and that altered gene expression can cause disease (particularly cancer) and some manifestations of aging. As a first step toward testing this hypothesis, it is essential to acquire more complete information on the expression of transposons in normal and diseased cells. Furthermore, if transposon expression is closely linked to the development or progression of cancer or aging, then the ability to monitor such expression could have diagnostic utility. DNA array technology is coming into wide use to compare patterns of gene expression in different types of cells. We propose to adapt this method to the study of transposon expression. We will clone examples of all known classes of mouse and human transposon, and study transposon expression in: 1. Normal mice, at intervals from the earliest phase of development to old age, and 2. Human cancers of a variety of types. These studies will provide information of fundamental significance for mammalian biology, and also have the potential to lead to improved diagnosis of disease.Read moreRead less
A new paradigm of gene regulation - implications in embryogenesis and disease. The proposed analysis of a new paradigm of gene regulation will provide a new key to understanding genome function and inform some of the most compelling biological issues of our time such as stem cell biology, tissue and organ regeneration and genetic programming. The insights and technologies developed in this program will be widely applicable in biotechnological and pharmacogenomic research in Australia and worldwi ....A new paradigm of gene regulation - implications in embryogenesis and disease. The proposed analysis of a new paradigm of gene regulation will provide a new key to understanding genome function and inform some of the most compelling biological issues of our time such as stem cell biology, tissue and organ regeneration and genetic programming. The insights and technologies developed in this program will be widely applicable in biotechnological and pharmacogenomic research in Australia and worldwide, and assert Australia's leadership in this area of research.Read moreRead less
Lungfish Paired Fins and the Origin of Limbs as an Evolutionary Novelty. This project will utilise a uniquely Australian animal, the lungfish, to address a hitherto unresolved problem of considerable scientific significance - how a fish fin evolved into a tetrapod (four-legged animal) limb. The Australian lungfish is the most primitive of the four surviving genera of lobe-finned fish and is recognised as the closest living ancestor to the tetrapods. It is listed as 'vulnerable' in its native ha ....Lungfish Paired Fins and the Origin of Limbs as an Evolutionary Novelty. This project will utilise a uniquely Australian animal, the lungfish, to address a hitherto unresolved problem of considerable scientific significance - how a fish fin evolved into a tetrapod (four-legged animal) limb. The Australian lungfish is the most primitive of the four surviving genera of lobe-finned fish and is recognised as the closest living ancestor to the tetrapods. It is listed as 'vulnerable' in its native habitat. Macquarie University, however, has the only captive breeding population of lungfish in the world. We are thus uniquely placed to address critically important questions concerning the evolution of fish into tetrapods. Read moreRead less