The Establishment Of Epigenetic Marks At Metastable Epialleles In The Mouse
Funder
National Health and Medical Research Council
Funding Amount
$372,750.00
Summary
Occasionally, identical twins are found to have distinctly different characteristics, such as eye colour or severity of genetic disease, that clearly cannot be explained by their genetic makeup, and are unlikely to be the result of environmental differences. In genetically identical mice, similar cases exist, where some mice have a yellow coat and others a brown coat. In instances such as these, a growing body of evidence suggests that certain modifications to genes are responsible. These modifi ....Occasionally, identical twins are found to have distinctly different characteristics, such as eye colour or severity of genetic disease, that clearly cannot be explained by their genetic makeup, and are unlikely to be the result of environmental differences. In genetically identical mice, similar cases exist, where some mice have a yellow coat and others a brown coat. In instances such as these, a growing body of evidence suggests that certain modifications to genes are responsible. These modifications are not traditional DNA mutations, but are chemical modifications of the basic sequence. Currently, we do not know when these DNA modifications are established during foetal development. We will use the mouse coat colour gene mentioned above to investigate when the different physical characteristics are established in embryonic development. Indeed, there is increasing evidence that critical periods exist in human foetal development where minor environmental or nutritional changes can affect long-term health of the adult. Perhaps the establishment of the DNA modifications are under an environmental or nutritional influence. Further study of when and how the DNA modifications are set-up during embryonic development is necessary in order to understand these events.Read moreRead less
A Random Mutagenesis Screen To Identify Modifiers Of Epigenetic Phenomena In The Mouse.
Funder
National Health and Medical Research Council
Funding Amount
$680,750.00
Summary
In recent months, both the human and mouse genome projects have been completed. The main focus now for mammalian geneticists is to discover the function of the genes sequenced in these initiatives. One way to achieve this goal is by random mutagenesis followed by screening of mice for novel phenotypes. In the mouse, ethylnitosourea (ENU) is a chemical that can be used to perform the mutagenesis. ENU causes mutations in sperm. We are using ENU mutagenesis to search for genes that modify epigeneti ....In recent months, both the human and mouse genome projects have been completed. The main focus now for mammalian geneticists is to discover the function of the genes sequenced in these initiatives. One way to achieve this goal is by random mutagenesis followed by screening of mice for novel phenotypes. In the mouse, ethylnitosourea (ENU) is a chemical that can be used to perform the mutagenesis. ENU causes mutations in sperm. We are using ENU mutagenesis to search for genes that modify epigenetic states. Epigenetic modifications are alterations in the genome that do not change the DNA sequence, yet silence the expression of genes. Silencing occurs on a cell-by-cell basis within a tissue resulting in mosaic expression. Silencing can also occur between individuals of the same genetic makeup. For example, identical twins are occasionally found that have distinctly different characteristics, such as eye colour or severity of genetic disease. These differences may be the result of variable epigenetic modifications. However, very little is known about how these variable epigenetic modifications are controlled. We wish to find the proteins involved in establishing and maintaining epigenetic states. It is likely that these processes play a fundamental role in the determination of phenotype, both in normal development and disease.Read moreRead less
Regulation Of Tissue-type Plasminogen Activator Gene Expression In Endothelial Cells And In Transgenic Mice
Funder
National Health and Medical Research Council
Funding Amount
$244,009.00
Summary
Tissue-type plasminogen activator (t-PA) is an enzyme which plays an important role in the removal of blood clots from the circulation. One of the major sites of production of t-PA are endothelial cells which line the blood vessel wall. The rate of t-PA production is greatly influenced by factors released from other cells. One of these factors is tumour necrosis factor (TNF). The t-PA gene is switched off in endothelial cells exposed to TNF. One of the aims of this project is to understand how t ....Tissue-type plasminogen activator (t-PA) is an enzyme which plays an important role in the removal of blood clots from the circulation. One of the major sites of production of t-PA are endothelial cells which line the blood vessel wall. The rate of t-PA production is greatly influenced by factors released from other cells. One of these factors is tumour necrosis factor (TNF). The t-PA gene is switched off in endothelial cells exposed to TNF. One of the aims of this project is to understand how the t-PA gene is suppressed by TNF in human endothelial cells and in transgenic mice. The transgenic mice we have available express the regulatory region of the t-PA gene (called the gene promoter) connected to a reporter gene called LacZ. We will use these animals to visualise the expression pattern of LacZ expression under normal conditions and in mice treated with TNF. The results of these experiments will provide new information as to how the t-PA gene is controlled in cells and in the body.Read moreRead less
Identification Of Critical Regulatory Elements In The BRCA1 Gene
Funder
National Health and Medical Research Council
Funding Amount
$227,036.00
Summary
Breast cancer affects approximately one in ten women and is therefore a major health problem. In order to improve the diagnosis, treatment and prognosis of this disease, it is critical to understand the molecular defects that contribute to disease initiation and progression. Over the last twenty years significant progress has been made in this regard, however there still remain a considerable number of unanswered questions. For example, it is not yet clear precisely what contribution each of the ....Breast cancer affects approximately one in ten women and is therefore a major health problem. In order to improve the diagnosis, treatment and prognosis of this disease, it is critical to understand the molecular defects that contribute to disease initiation and progression. Over the last twenty years significant progress has been made in this regard, however there still remain a considerable number of unanswered questions. For example, it is not yet clear precisely what contribution each of these genes makes. This is largely due to limitations in current mutation detection strategies and an incomplete understanding of all of the genetic elements for which disruption can lead to loss of gene function. This propsal aims to identify all of the genetic elements critical for the expression of an important breast cancer gene called BRCA1. Furthermore, it aims to determine the status of these elements in breast cancer patients, thus expanding our knowledge of the actual contribution disruption of this gene makes to this disease.Read moreRead less
Analysis Of Very Early Cancer-related Methylation Abnomalities
Funder
National Health and Medical Research Council
Funding Amount
$422,310.00
Summary
The factors that are involved in triggering cancer are still unknown. Increasing evidence however indicates that the DNA in the pre-cancer cell becomes modified leading to altered expression of important genes called tumour suppressor genes. Often the DNA is deleted or mutated but it can also become chemically changed by a process called DNA methylation. We have found that an important tumour suppressor gene called p16 is inactivated and chemically methylated in breast epithelial cells at the st ....The factors that are involved in triggering cancer are still unknown. Increasing evidence however indicates that the DNA in the pre-cancer cell becomes modified leading to altered expression of important genes called tumour suppressor genes. Often the DNA is deleted or mutated but it can also become chemically changed by a process called DNA methylation. We have found that an important tumour suppressor gene called p16 is inactivated and chemically methylated in breast epithelial cells at the stage when the cell changes to a pre-cancer cell. This grant is aimed at finding what triggers the silencing and methylation of the p16 gene in this early pre-cancer stage. We also plan to identify other genes are methylated and undergo inactivation the pre-cancer breast cells. These results will have an impact on understanding the molecular mechanism that makes a breast cell susceptible to cancer and may lead to insights into new prevention and treatment strategies.Read moreRead less