Post Transcriptional Regulation Of The Plasminogen Activator Inhibitor Type 2 Gene
Funder
National Health and Medical Research Council
Funding Amount
$241,527.00
Summary
The process of wound healing, removal of blood clots, cell migration and the metastatic spread of cancers requires the recruitment of specialised proteases. These proteases act primarily to degrade other proteins, mainly in the extracellular space, which in turn allow cells to move around, wounds to close, and blood clots to disappear. The plasminogen activating system is one of the most important enzyme systems involved in these events. One of the proteases that cleaves plasminogen to its activ ....The process of wound healing, removal of blood clots, cell migration and the metastatic spread of cancers requires the recruitment of specialised proteases. These proteases act primarily to degrade other proteins, mainly in the extracellular space, which in turn allow cells to move around, wounds to close, and blood clots to disappear. The plasminogen activating system is one of the most important enzyme systems involved in these events. One of the proteases that cleaves plasminogen to its active form, plasmin, is urokinase (u-PA). Plasminogen activator inhibitor type 2 (PAI-2) is a serine protease inhibitor that inhibits u-PA activity. The degree of u-PA activity therefore depends on the relative levels of u-PA and PAI-2. In addition to controlling u-PA activity, PAI-2 also influences intracellular events including cell proliferation, differentiation and apoptosis. PAI-2 protein and mRNA levels are substantially modulated by many cytokines and growth factors. This project addresses the molecular mechanisms underlying the regulation of PAI-2 gene expression. We have recently shown that a significant degree of PAI-2 regulation occurs at the level of PAI-2 mRNA stability, and we have identified two regions within the PAI-2 mRNA that play a role in this process. Both regions provide binding sites for cellular proteins. We have identified one of these binding proteins to be HuR, a protein that has recently been shown to control the stability of other mRNAs. The specific aims of this project are firstly, to determine the role of HuR in the control of PAI-2 mRNA stability, and secondly, to clone a characterise the other PAI-2 mRNA binding proteins we have identifed. An understanding of how cells modulate levels of PAI-2 mRNA will significantly add to the broader field of gene regulation and may also provide new clues to influence PAI-2 levels in the body.Read moreRead less
I am a molecular biologist determining the mechanisms of eukaryotic mRNA translation and its regulation by RNA-binding proteins and noncoding RNA. In collaborative work I extend these basic science objectives into the medical research areas of cardiology
Post-transcriptional Regulation Of Plasminogen Activator Inhibitor 2 Gene Expression
Funder
National Health and Medical Research Council
Funding Amount
$508,838.00
Summary
Plasminogen activator inhibitor type 2 (PAI-2) is a protease inhibitor that has intracellular and extracellular functions. The PAI-2 gene is highly regulated at the level of PAI-2 mRNA stability. We have identified regions within the PAI-2 transcript essential for this regulation and a number of novel proteins that engage these regions. This project is aimed at understanding how these and other proteins control PAI-2 expression at the mRNA level.
Molecular Mechanisms For The Cell-type Specific Regulation Of The Tissue-type Plasminogen Activator Gene
Funder
National Health and Medical Research Council
Funding Amount
$490,500.00
Summary
Tissue-type plasminogen activator (t-PA) is an important enzyme that is widely known for its ability to remove blood clots. More recently, t-PA has been shown to influence memory development and under pathological conditions can promote neuronal cell death. t-PA is produced by many cells including the endothelial cells that line the blood vessels, fibroblasts, as well as cells within the central nervous system. The t-PA gene is regulated very differently in these cell types and this project will ....Tissue-type plasminogen activator (t-PA) is an important enzyme that is widely known for its ability to remove blood clots. More recently, t-PA has been shown to influence memory development and under pathological conditions can promote neuronal cell death. t-PA is produced by many cells including the endothelial cells that line the blood vessels, fibroblasts, as well as cells within the central nervous system. The t-PA gene is regulated very differently in these cell types and this project will address the mechanisms underlying the cell-type specific regulation of the t-PA gene. Endothelial cells, fibroblasts and neuronal cell cultures will be used to study the regulation of t-PA expression. Information gained will not only add to the understanding of the broader field of gene regulation, but may also provide clues to manipulate the expression of the t-PA gene in different cells.Read moreRead less
Inherited disorders of the blood, such as sickle-cell anaemia and thalassaemia, result from mutations in the genes that produce haemoglobin. Current treatments can partially alleviate some of the debilitating symptoms of these diseases but these treatments have significant side effects, and despite the best efforts of clinicians, many patients succumb to their conditions at an early age. It has been observed that certain individuals exhibit a milder form of the disease, as a consequence of the r ....Inherited disorders of the blood, such as sickle-cell anaemia and thalassaemia, result from mutations in the genes that produce haemoglobin. Current treatments can partially alleviate some of the debilitating symptoms of these diseases but these treatments have significant side effects, and despite the best efforts of clinicians, many patients succumb to their conditions at an early age. It has been observed that certain individuals exhibit a milder form of the disease, as a consequence of the reactivation of their foetal haemoglobin genes, (a distinct set of genes that would have been active in utero but are normally silenced around the time of birth). It is widely accepted that if pharmaceutical means can be found for reactivating the foetal haemoglobin genes then many patients would benefit. The regulation of the foetal globin genes, like most human genes, is complicated and there are few obvious means of increasing their activity. Nevertheless, it is believed that by investigating the molecular mechanisms by which they are controlled it will be possible to devise therapeutic agents that mimic these mechanisms or to develop agents that prevent the shutdown of the foetal genes around birth. To this end we have been working on the molecules that regulate the activity of the haemoglobin genes. We have recently cloned a number of DNA-binding proteins, and their co-factors, that appear to be involved in silencing foetal globin gene expression. This grant proposal is concerned with learning how these new molecules operate to silence gene expression as a first step towards designing agents that will prevent the silencing.Read moreRead less
Translational Control Of Gene Expression And The Choice Between Cell Death And Proliferation
Funder
National Health and Medical Research Council
Funding Amount
$378,000.00
Summary
Proteins carry out most enzymatic and structural functions in a cell. Thus, the kinds of protein molecules that are found in a given cell determine its characteristics and cells respond to changes in their environment by adjusting the abundance of some or many proteins in their collection. The instructions for the assembly of proteins are encoded in the genes and this information is expressed via intermediary molecules called messenger (m)RNA. Both, transcription of the genes into mRNA molecules ....Proteins carry out most enzymatic and structural functions in a cell. Thus, the kinds of protein molecules that are found in a given cell determine its characteristics and cells respond to changes in their environment by adjusting the abundance of some or many proteins in their collection. The instructions for the assembly of proteins are encoded in the genes and this information is expressed via intermediary molecules called messenger (m)RNA. Both, transcription of the genes into mRNA molecules and their subsequent translation by the ribosomes into protein are tightly controlled steps in the gene expression pathway. Erroneous gene expression is a major factor in human disease and dysregulation of translation is linked to a growing spectrum of illnesses such as cancer and cardiovascular disease, viral infection, and less frequent hereditary syndromes. The project proposed here is prompted by emerging evidence for a role of translational regulation in controlling the balance between cell death and survival. Tipping this balance has disastrous consequences for an organism as evidenced by its involvement in many major disorders (e. g. stroke, heart failure, neurodegeneration, AIDS, cancer, autoimmunity). Our aim is to test the hypothesis that a putative translational regulator termed p97-DAP5-NAT1, and a specialised mechanism of translation initiation by internal ribosome entry are important for the maintenance of this balance. To investigate this, we will employ DNA chips, a novel tool from Genomics research that allows the measurement of the levels of thousands of mRNA molecules in a single experiment. It is conceivable that knowledge of these special mechanisms of translation will lead to novel targets for therapeutic intervention, and this work will contribute some of the experimental tools to explore these avenues in the future.Read moreRead less
Functional Analysis Of The P160 Myb-binding Protein - A Regulator Of Multiple Transcription Factors?
Funder
National Health and Medical Research Council
Funding Amount
$376,697.00
Summary
The c-myb gene is a key molecular regulator of normal blood cell production, but alterations to this gene can also lead to leukaemia. The protein (Myb) encode by the c-myb gene acts as a transcription factor, ie, it controls the activity of other genes. There is good evidence that interactions with other proteins can regulate the activity of Myb. Our laboratory has identified what we believe is one such protein - p160 - that binds to a part of Myb that reduces its activity, and thus that is like ....The c-myb gene is a key molecular regulator of normal blood cell production, but alterations to this gene can also lead to leukaemia. The protein (Myb) encode by the c-myb gene acts as a transcription factor, ie, it controls the activity of other genes. There is good evidence that interactions with other proteins can regulate the activity of Myb. Our laboratory has identified what we believe is one such protein - p160 - that binds to a part of Myb that reduces its activity, and thus that is likely to be responsible for regulating Myb. However, it has recently become apparent that p160 interacts with a number of other transcription factors in addition Myb. The primary aim of this project is to elucidate precisely how p160 interacts with Myb and what the consequences of this interaction are. A range of experimental approaches, which range from in vitro to genetic studies, will be employed to do this. We will test a specific role of p160 suggested by our preliminary studies - that of a transporter of transcription factors between the nucleus and the cytoplasm of the cell. Because of the wide range of transcription factors that p160 interacts with, its effects on the function of the cell are likely to be profound. For this same reason, it is difficult to specifically predict the possible medical-health implications of this work However, what we know to date is consistent with a role for p160 as a tumour suppressor gene. Moreover, parts of this project aim to generate genetic information and tools which will help in determining whether p160 does play such a role and generally, in identifying any other associations of p160 with particular diseases.Read moreRead less
Identifying Target Molecules Regulated By Nuclear Retention In Cancer And Development
Funder
National Health and Medical Research Council
Funding Amount
$267,173.00
Summary
Human DNA contains approximately 30000 genes; only twice as many as worms and flies, ten times as many as bacteria, and fewer than rice. Humans, however have considerably more complexity than these lower organisms. What are the factors responsible for the additional complexity? In the simplest scenario, one gene is transcribed to produce one message (mRNA), which is the blueprint for producing one protein. We now know that there are numerous mechanisms that potentially allow many different prote ....Human DNA contains approximately 30000 genes; only twice as many as worms and flies, ten times as many as bacteria, and fewer than rice. Humans, however have considerably more complexity than these lower organisms. What are the factors responsible for the additional complexity? In the simplest scenario, one gene is transcribed to produce one message (mRNA), which is the blueprint for producing one protein. We now know that there are numerous mechanisms that potentially allow many different proteins to be made from one gene. Also, it is the decisions about which gene will be made ( expressed ) into protein where and when in development, that is critical for our complexity. The control of gene expression is thus fundamental to all cellular processes and many diseases such as cancer and metabolic disorders are associated with some aspect of aberrant gene expression. The production of mRNA from DNA occurs in the human cell nucleus. The nucleus is not simply a bag of DNA, in fact, many important nuclear factors are organised into sub-nuclear bodies . Recently we discovered a novel sub-nuclear body, the paraspeckle and have been identifying its components and their function. Paraspeckles are involved in a previously undiscovered mechanism of the control of gene expression. Here, certain mRNA molecules are trapped in the nucleus until a signal is received from elsewhere in the cell, which causes the mRNA to be released and protein to be made. This Rapid Release Nuclear Retention mechanism effectively allows the quick production of specific proteins to be made on demand. In this project we propose to use cutting edge molecular and cell biology techniques to identify the special mRNA molecules that are trapped in paraspeckles in cancer cells. This will increase our understanding about the molecular details of this process, ultimately leading to potential uses in gene therapy, and should result in the discovery of important targets for cancer treatment.Read moreRead less
Alternative Splicing Of GLI1 And Its Role In Tumourigenesis
Funder
National Health and Medical Research Council
Funding Amount
$392,640.00
Summary
Gene expression involves the transfer of information from DNA to proteins and is mediated by a third molecule called messenger RNA (mRNA). The process is tightly controlled since unregulated gene expression is harmful and can result in diseases such as developmental disorders and cancer. The genetic information in DNA is first copied to an RNA molecule in a process called transcription. This RNA molecule then undergoes a series of maturation steps before the information it carries can be transla ....Gene expression involves the transfer of information from DNA to proteins and is mediated by a third molecule called messenger RNA (mRNA). The process is tightly controlled since unregulated gene expression is harmful and can result in diseases such as developmental disorders and cancer. The genetic information in DNA is first copied to an RNA molecule in a process called transcription. This RNA molecule then undergoes a series of maturation steps before the information it carries can be translated into a protein. One of these maturation steps involves the removal of sequences (called introns) that do not contain protein coding information from the sequences (called exons) that will be present in the mature mRNA. Some genes contain no introns while others contain 20 or more, which are dispersed throughout the gene. The removal of intron sequences from immature RNA molecules is called splicing and is carried out by a macromolecular complex that recognises the intron sequences, cuts them out of the RNA and then rejoins the RNA to make a contiguous sequence. This process has to be precise otherwise spurious sequences will be present in the mRNA, which will result in the production of abnormal proteins. In addition, for some genes mRNAs are produced that have differences in a portion of their sequence. These alternative sequences are generated by the inclusion or exclusion of alternative exons. Because, RNA splicing is critical to the production of mature mRNAs and because it can generate sequence diversity it is tightly regulated. We have recently found that expression of a cancer gene (called GLI1) is regulated in part by the use of alternative GLI1 mRNAs. Moreover, we found that the expression of one of these alternative GLI1 mRNAs is associated with skin cancer. In this project we will investigate the molecular mechanisms that regulate alternative splicing in GLI1 and identify whether changes in these mechanisms result in cancer.Read moreRead less
A Structural And Functional Basis For The Regulation Of Gene Expression By Nuclear Retention Of RNA
Funder
National Health and Medical Research Council
Funding Amount
$504,097.00
Summary
The nuclear retention mechanism is a novel way used by cells to control which genes are made into proteins - a fundamental process for all diseases, particularly cancers. This project will employ cutting edge structural and proteomic techniques to determine the molecular details underpinning nuclear retention. These insights will be important for the development of new tissue-restricted gene therapy applications and drugs targeting the cancers that rely on this mechanism.