The Role Of Transcription Factors In Regulating The First Round Of Gene Expression In The Early Embryo.
Funder
National Health and Medical Research Council
Funding Amount
$348,931.00
Summary
Assisted reproductive technologies result in a high incidence of multiple births. This is and adverse outcome that requires correction. It stems from the common transfer of several embryos due to the low chance of an individual embryo made by IVF resulting in a baby. This project will determine the normal pattern of gene expression in the embryo and define: (1) how it is adversely changed as a consequence of IVF; and (2) the extent that these changes are a cause of the low embryo viability.
Mechanisms Of P53 Induced Embryopathy After In Vitro Fertilisation.
Funder
National Health and Medical Research Council
Funding Amount
$483,737.00
Summary
Assisted reproductive technologies (ART) cause many embryos not to survive to birth. We have shown that IVF causes increased expression of protein normally involved in stopping cells from dividing. This is a major cause of embryo death after IVF. This project will determine how this protein acts to cause embryonic death and assess strategies to prevent it.
The normal processes of development of the embryo require that the information encoded in chromosomes be reprogrammed soon after fertilization. This process is rather fragile and disturbance of the early embryo can upset it. Recent studies for the chief investigator's provide new understanding of the normal processes of reprogramming. The project will explore and validate the implications of these new discoveries and provide a basis for future alleviation of abnormalities to development.
Male Infertility And Defective Sperm-oocyte Interaction
Funder
National Health and Medical Research Council
Funding Amount
$244,614.00
Summary
Infertility affects 15% of people and although not usually ill, they are extremely distressed by the condition. In vitro fertilisation (IVF) with normal sperm and intracytoplasmic sperm injection for sperm defects, can assist such patients have a family, but these treatments are expensive and not always successful. The causes of male infertility are largely unknown, diagnostic methods are crude and there is usually no treatment to promote natural conception. Conventional semen analysis provides ....Infertility affects 15% of people and although not usually ill, they are extremely distressed by the condition. In vitro fertilisation (IVF) with normal sperm and intracytoplasmic sperm injection for sperm defects, can assist such patients have a family, but these treatments are expensive and not always successful. The causes of male infertility are largely unknown, diagnostic methods are crude and there is usually no treatment to promote natural conception. Conventional semen analysis provides limited information on fertilising ability. Our work over 15 years has shown that many patients go undiagnosed, particularly those with defects impairing fertilisation. During human fertilisation, sperm bind to the zona pellucida, a coat around the egg, via the membrane over a cap like structure on the sperm head called the acrosome. Binding of a sperm triggers the acrosome reaction, the process by which the membranes covering the acrosome fuse and the acrosomal contents are released. The sperm then penetrates the zona pellucida, binds to the membrane of the egg and is taken into the cytoplasm. We have developed tests to assess sperm binding to the zona pellucida and the acrosome reaction using eggs that failed to fertilise during clinical IVF. These tests show defects of sperm binding to the zona pellucida and the zona pellucida induced acrosome reaction are present in over 25% of patients without other obvious causes for their infertility. The men are severely infertile but have normal sperm by conventional tests. In this project we will determine if there are changes in membrane proteins in sperm which do not bind to the zona pellucida or undergo the acrosome reaction. We will categorise patients on the responses of their sperm to activation of key enzymes and other regulatory molecules involved in the fertilisation process. This will allow us to select subjects for further examination of protein abnormalities and genetic causes of the conditions.Read moreRead less
We propose to determine if a recently discovered biological mechanism plays crucial roles in the development of eggs and sperm. To achieve this, we will remove or mutate this pathway specifically in developing eggs and sperm , then examine the effect. Preliminary results indicate that the mechanism does play important roles mutated eggs fail to complete maturation. These studies will tell us more about what makes a healthy egg and sperm, and are relevant to female and male fertility.
Functional Genomic Analysis Of The Role Of P53 In Early Embryo Death After Assisted Reproductive Technologies (ART).
Funder
National Health and Medical Research Council
Funding Amount
$227,036.00
Summary
Assisted reproductive technologies (ART, such as IVF and related techniques) are successful treatments for most forms of infertility. ART are expensive therapies and much of this cost is related to the relative inefficiency of the technology. Much of this is due to the high mortality of the resulting embryos. Typically, 45-80% of embryos produced by ART do not survive the first week. Consequently the chance of any individual embryo resulting in a successful birth is not high. There has been only ....Assisted reproductive technologies (ART, such as IVF and related techniques) are successful treatments for most forms of infertility. ART are expensive therapies and much of this cost is related to the relative inefficiency of the technology. Much of this is due to the high mortality of the resulting embryos. Typically, 45-80% of embryos produced by ART do not survive the first week. Consequently the chance of any individual embryo resulting in a successful birth is not high. There has been only modest increments in embryo survival in recent years. The low cahnce of individual embryos resulting in a baby means that: (1) generally several treatment cycles are required; (2) superovulation is used to maximise the number of embryos produced giving an accumulation of unwanted cryopreserved embryos; (3) more than one embryo is generally transferred resulting in a significant incidence of multiple pregancies. The high mortality of the early embryo seems to be a general feature of IVF but its causes and effectors are not known. It has recently been established that it largely occurs due to a form of cell 'suicide' known as apoptosis. This form of cell death has important normal functions: its activation allows for cells that are no longer required to be removed, allowing the remodelling of tissues and it also serves to remove cells that are irreversibly damaged. p53 is a protein that has the ability to 'sense' cell stress and damage and to direct the cell to undergo apoptosis if the stress is severe. This project will examine if ART cause increased expression of p53 and whether this elevation of p53 causes embryonic cell death. We will examine the factirs that control p53 expression in the embryo. using mice with mutations that stop the function of p53 and several of its regulatory proteins. Experiments will determine the susceptibility of embryos possessing these mutations and will therefore allow us to define the proteins causing apoptosis after ART.Read moreRead less
Characterisation Of The Pathways Leading To DNA Demethylation In The Embryo.
Funder
National Health and Medical Research Council
Funding Amount
$634,573.00
Summary
Complex living creatures like humans have specialised cells that co-operate to form important organs like brains and reproductive organs. Specialised cells have specific genes locked on or off. When a sperm fertilises an egg, all the switches of the genes that are locked on or off get reset to neutral so that the fertilised egg can divide and grow into all cell types in the body. We do not know how this resetting happens in the egg. This project seeks to discover the mechanism involved.
The Role Of Oocyte-secreted Proteins In Primate Follicular Cell Function
Funder
National Health and Medical Research Council
Funding Amount
$176,320.00
Summary
Mammalian eggs grow and develop in fluid filled sacks in the ovary called follicles. These structures nurture the egg for prolonged periods preparing it for ovulation and fertilisation. It has been known for some time that the quality of the follicular environment determines, in part, the developmental potential of the egg. Recent studies in mice have shown that the interaction between the egg and the follicle is in fact a two-way process, and that the egg is able to influence development of the ....Mammalian eggs grow and develop in fluid filled sacks in the ovary called follicles. These structures nurture the egg for prolonged periods preparing it for ovulation and fertilisation. It has been known for some time that the quality of the follicular environment determines, in part, the developmental potential of the egg. Recent studies in mice have shown that the interaction between the egg and the follicle is in fact a two-way process, and that the egg is able to influence development of the follicle. This project proposes to investigate these processes further in the laboratory mouse using new reagents available to us, and to extend these findings by investigating this communication pathway for the first time in a primate species. Because of the difficulty of undertaking such research using human material, we will use the marmoset monkey as a model. This exciting new development has important implications for women's health because it may help us understand why some women suffer from premature menopause or cystic ovaries, and in the longer term could help in the development of new types of contraceptives.Read moreRead less