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
Post Transcriptional Regulation Of Plasminogen Activator Inhibitor Type 2 Gene Expression
Funder
National Health and Medical Research Council
Funding Amount
$318,000.00
Summary
The process of wound healing, cell migration and the spread of cancers requires the recruitment of specialised proteases to the cell surface . These proteases act to degrade other proteins, mainly in the extracellular space, which in turn allows cells to move around, wounds to close, and blood clots to disappear. The plasminogen activating system is one of the enzyme systems involved in these events. One of the proteases that cleaves plasminogen to its active form, plasmin, is urokinase (u-PA) a ....The process of wound healing, cell migration and the spread of cancers requires the recruitment of specialised proteases to the cell surface . These proteases act to degrade other proteins, mainly in the extracellular space, which in turn allows cells to move around, wounds to close, and blood clots to disappear. The plasminogen activating system is one of the enzyme systems involved in these events. One of the proteases that cleaves plasminogen to its active form, plasmin, is urokinase (u-PA) and the activity of u-PA is regulated by its natural inhibitor called plasminogen activator inhibitor type 2 (PAI-2). u-PA is strongly implicated in the progression of metastatic cancer and high levels of PAI-2 relative to u-PA is regularly seen as a positive prognostic indicator for metastatic cancer. In this situation, PAI-2 acts to limit the activity of u-PA thereby restricting the migration potential of the cancer. PAI-2 is unusual because it exists both inside and outside the cell. Outside the cell, PAI-2 acts to inhibit u-PA activity, while inside the cell, PAI-2 also plays a role in the inhibition of cell growth and differentiation. It is therefore important to understand how the production of PAI-2 is regulated in cells. A significant component of PAI-2 regulation occurs post-transcriptionally, particularly at the level of mRNA stability. We have identified some of the proteins that bind to PAI-2 mRNA and influence its longevity in the cell. This project aims to further undertand how these as well as other PAI-2 mRNA binding proteins influence the expression of the PAI-2 gene.Read moreRead less
MicroRNA Networks That Safeguard The Functional Program Of Regulatory T Cells
Funder
National Health and Medical Research Council
Funding Amount
$457,941.00
Summary
A newly discovered group of molecules termed microRNAs are thought to function as rheostats for the activity of genes. We have shown that these molecules are critical for the function of an immune cell type termed regulatory T cells. Without these cells, the immune system is unable to prevent uncontrolled and destructive inflammation. This proposal aims to utilize diverse technologies to uncover the precise molecular mechanisms by which microRNAs safeguard the function of regulatory T cells.
MRNA Surveillance In Human Disease: Molecular Determinants Of Nonsense-mediated MRNA Decay
Funder
National Health and Medical Research Council
Funding Amount
$474,517.00
Summary
Inherited diseases are a common cause of human disability, illness and suffering. It has been estimated that 5-10% of the population will be affected by disorders with a genetic component. Thus studies on mechanisms of inherited diseases, especially those relating to genetic mechanisms with relevance across a wide range of individual disorders and gene mutations, are of great significance in diagnosis, molecular pathology and the eventual development of therapeutics. While there are many types o ....Inherited diseases are a common cause of human disability, illness and suffering. It has been estimated that 5-10% of the population will be affected by disorders with a genetic component. Thus studies on mechanisms of inherited diseases, especially those relating to genetic mechanisms with relevance across a wide range of individual disorders and gene mutations, are of great significance in diagnosis, molecular pathology and the eventual development of therapeutics. While there are many types of mutations, one relatively common type is called a premature termination mutation. Premature termination mutations introduce an inappropriate genetic signal that tells the cells to stop the formation of proteins before they are complete. This would result in the production of a protein that is shorter than normal, and these short proteins could be quite abnormal and drastically affect the normal function of cells. To overcome this, cells have developed elegant strategies that involve the deployment of quality control, or surveillance, mechanisms to remove the mutant gene product before it can be converted into an abnormal protein. This process is called nonsense mediated decay. Nonsense mediated decay is a complex process and some of the key components have been identified by studies on a small number of genes. However, our studies have identified several previously unknown aspects of the process that suggest that the currently held view of how nonsense mediated decay works is only the beginning of the story and further important complexity exists. The proposed research will explore the basic mechanisms of the surveillance process and determine the signals that initiate nonsense mediated decay. Since premature termination mutations cause one-third of all inherited genetic disorders, our studies will provide new insights into the surveillance mechanisms and will have wide applicability to our understanding of the basis of inherited disease.Read moreRead less
Role Of MicroRNAs In The Control Of MRNA Translation
Funder
National Health and Medical Research Council
Funding Amount
$360,500.00
Summary
This project studies the function of a recently discovered class of ribonucleic acid (RNA) molecules termed microRNAs (miRNAs). They appear to have very important functions in all multicellular organisms, since many of them have undergone little change over hundreds of millions of years. At present we know that miRNAs probably work by regulating the efficiency with which messenger RNAs (mRNAs) are translated into protein molecules. However we do not know how they accomplish this, or which mRNAs ....This project studies the function of a recently discovered class of ribonucleic acid (RNA) molecules termed microRNAs (miRNAs). They appear to have very important functions in all multicellular organisms, since many of them have undergone little change over hundreds of millions of years. At present we know that miRNAs probably work by regulating the efficiency with which messenger RNAs (mRNAs) are translated into protein molecules. However we do not know how they accomplish this, or which mRNAs are regulated by miRNAs. Our work to date has suggested to us that miRNAs may act in combination with one another on mRNAs, so that the effect on a given mRNA depends on just which miRNAs are present, and how abundant they are. We propose to construct a system in which the function of miRNAs can be studied in vitro, using crude cell extracts that are known to perform mRNA translation and related functions. This will, for the first time, make it possible to test miRNAs in carefully controlled conditions, and ask which steps in translation they affect. We will be able to investigate just how the pairing of miRNA and mRNA sequences determines the ability of a miRNA to act on a specific mRNA, and to confirm that a given miRNA actually does regulate a specific mRNA. To facilitate this goal, we will use three methods to isolate mRNAs that are targets of miRNA regulation. Each of these methods relies on the physical interaction of miRNA and mRNAs in cell extracts. In one method, we will attach a tag to a miRNA, and use the tag to pull out associated mRNAs. In another method, we will use an antibody to a protein that is thought to associate with all miRNAs. The antibody should pull out any mRNAs associated with the miRNA-protein complex. Finally, we will identify mRNAs that have responded to the presence of a miRNA by changing the efficiency with which they are translated. These experiments will provide essential knowledge about an extremely important biological system.Read moreRead less
Heterogeneous Nuclear Ribonucleoprotein Role In Alternative RNA Splicing And Human Disease
Funder
National Health and Medical Research Council
Funding Amount
$254,250.00
Summary
Control of the use of DNA, gene expression, is vital to all living organisms, especially in development and disease. The information in the genes of DNA is transferred to an intermediate molecule, mRNA, in a process called transcription. The genetic information in the mRNA is subsequently used, in the process called translation, to make the protein encoded by the original gene. The switching on and off of DNA appears to be most frequently controlled at the transcription step but recently it has ....Control of the use of DNA, gene expression, is vital to all living organisms, especially in development and disease. The information in the genes of DNA is transferred to an intermediate molecule, mRNA, in a process called transcription. The genetic information in the mRNA is subsequently used, in the process called translation, to make the protein encoded by the original gene. The switching on and off of DNA appears to be most frequently controlled at the transcription step but recently it has become apparent that there are many post-transcriptional events that govern how efficiently the genetic information is ultimately converted to protein molecules. An important step is the cutting out of parts (introns) of the RNA molecule that is copied from DNA, and splicing of the retained sections (exons). During this process the RNA may also lose one or more of its exons. As a result of this variable retention of exons a single gene may produce many isoforms of the protein it encodes. By this mechanism the roughly 30,000 genes in the human genome can give rise to potentially hundreds of thousands of proteins. RNA splicing connects to cancer in two ways. First, changes in the concentrations of the proteins that control splicing may change the isoforms, resulting in changes that lead to uncontrolled cell proliferation. Secondly, DNA mutations that affect the splicing process can also vary the ratios of the isoforms produced from a gene: if this occurs in a protein that is involved in the growth of cells this too may lead to cancer. In this project we will study the molecular mechanism of this alternative splicing, and particularly a group of proteins that generally favour the excision of some exons, with a focus on cancer cells. Recent publications have highlighted the potential for the therapeutic use of drugs that target the splicing apparatus: it is anticipated that studies of alternative splicing will underpin development of new therapeutic agents.Read moreRead less