NUCLEAR AND TRANSGOLGI TARGETING AND MEMBRANE INDUCTION BY DENGUE NS5 RNA-DEPENDENT RNA POLYMERASE INTERDOMAIN REGION
Funder
National Health and Medical Research Council
Funding Amount
$450,750.00
Summary
Dengue virus is the causative agent of a mosquito-borne disease, Dengue fever, relevant to northern Queensland, where antibodies from a previous infection can complex with virus of a different serotype in a subsequent infection, and cause a severe, potentially fatal form of the disease (Dengue haemorrhagic fever-Dengue shock syndrome). The present proposal seeks to further understanding of the role of the dengue RNA-dependent RNA polymerase NS5, which is essential for viral RNA replication, with ....Dengue virus is the causative agent of a mosquito-borne disease, Dengue fever, relevant to northern Queensland, where antibodies from a previous infection can complex with virus of a different serotype in a subsequent infection, and cause a severe, potentially fatal form of the disease (Dengue haemorrhagic fever-Dengue shock syndrome). The present proposal seeks to further understanding of the role of the dengue RNA-dependent RNA polymerase NS5, which is essential for viral RNA replication, within the viral infectious cycle. We intend to examine the subcellular targeting properties of a short central region (the interdomain) of NS5, which appears to play multiple roles in targeting to both the perinuclear Golgi-membranes and to the nucleus, as well as in inducing intracellular membranes derived from the Golgi which are the site of viral replication. We will determine how NS5 localisation-membrane induction may differ in insect and primate cells, and attempt to isolate binding partners of NS5 from the nucleus and Golgi compartment of insect and primate cells using various different approaches. Our studies should assist in understanding NS5's critical role in the Dengue infectious cycle, and contribute towards devising new anti-viral strategies such as vaccination and-or therapies targeted at the NS5 interdomain.Read moreRead less
Role Of The Microtubule Network In Nuclear Transport: Potential Use In Gene Delivery
Funder
National Health and Medical Research Council
Funding Amount
$491,767.00
Summary
Transport of key proteins that regulate growth and other processes, into and out of the nucleus, the site of gene transcription, is central to the function of eukaryotic cells. Knowledge of the process is largely based on studies using semi-intact cell systems, however, meaning that the role of cytoskeletal elements in nuclear transport has been largely overlooked. Intriguingly, in vivo studies, including our own relating to signalling molecules important in the regulation of cancer, clearly imp ....Transport of key proteins that regulate growth and other processes, into and out of the nucleus, the site of gene transcription, is central to the function of eukaryotic cells. Knowledge of the process is largely based on studies using semi-intact cell systems, however, meaning that the role of cytoskeletal elements in nuclear transport has been largely overlooked. Intriguingly, in vivo studies, including our own relating to signalling molecules important in the regulation of cancer, clearly implicate the cellular microtubule (MT) network as playing an integral role in nuclear import. We propose to carry out a detailed examination of the mechanistic basis of the dependence of nuclear import on the MT network of 3 molecules regulating cancer. We will compare the properties of these molecules to those of other nuclear localizing molecules, as well as examine the ability to mediate nuclear import of similar MT-associating sequences from viral and other proteins. The results will establish for the first time, the generality of the dependence of nuclear protein import on cytoskeletal elements. Since the movement of large DNA molecules by simple diffusion is a limiting factor in non-viral gene delivery approaches, the possibility of applying this knowledge to facilitate the transport of DNA encoding therapeutic gene products to the nucleus of target cells, will also be assessed for the first time. We will use the modular sequences that confer interaction with the MT network to assist gene transfer by including them in modular constructs we have designed with this in mind. We will thus be able to test directly for the first time whether MT-interaction can enhance the delivery of DNA to the nucleus and reporter gene expression, with obvious application in gene therapy approaches.Read moreRead less
The Tumour Cell-specific Nuclear Targeting Properties Of Chicken Anaemia Virus VP-3: Potential For Anti-tumour Therapy
Funder
National Health and Medical Research Council
Funding Amount
$465,210.00
Summary
Current trends indicate that cancer will cause 40% of all deaths in Australia by 2012, meaning that new anti-cancer strategies are urgently required. Our proposal intends to examine the subcellular targeting abilities of the unique tumour-cell specific agent apoptin (VP3 - viral protein 3), a small protein encoded by the genome of the chicken anaemia virus. Using various strategies, we have identified part of the apoptin molecule that confers efficient localisation in the nucleus of tumour cells ....Current trends indicate that cancer will cause 40% of all deaths in Australia by 2012, meaning that new anti-cancer strategies are urgently required. Our proposal intends to examine the subcellular targeting abilities of the unique tumour-cell specific agent apoptin (VP3 - viral protein 3), a small protein encoded by the genome of the chicken anaemia virus. Using various strategies, we have identified part of the apoptin molecule that confers efficient localisation in the nucleus of tumour cells, but not non-tumour cells. Our experimental program intends to define this tumour cell-specific targeting signal in detail, and determine the molecular basis of the differential subcellular localisation of apoptin in tumour compared to normal cells. This should contribute fundamental new information regarding the differences between cancer and normal cells. Additionally, we intend to optimise the targeting signal and perform initial experiments to test its efficacy in targeting anti-tumour drugs to the nucleus of tumour cells. Our long-term aim is to use the apoptin tumour cell-specific nuclear targeting signal as part of modular constructs to combat cancer efficiently, and above all, with minimal damage to normal cells and tissues.Read moreRead less
Approaches to combat AIDS and its causative agent, the human immunodeficiency virus HIV-1, have thus far proved ineffective. The proposed research program intends to investigate the nuclear import of two HIV-1 proteins which have central roles in HIV infection. We will apply our expertise in the area of the regulation of nuclear import of viral proteins, and build on our observations with respect to these proteins to attempt to establish the mechanistic basis of their nuclear import, and how thi ....Approaches to combat AIDS and its causative agent, the human immunodeficiency virus HIV-1, have thus far proved ineffective. The proposed research program intends to investigate the nuclear import of two HIV-1 proteins which have central roles in HIV infection. We will apply our expertise in the area of the regulation of nuclear import of viral proteins, and build on our observations with respect to these proteins to attempt to establish the mechanistic basis of their nuclear import, and how this differs from the conventional nuclear import pathways used by normal cellular proteins. We already have evidence that nuclear import of HIV-Tat is regulated in novel fashion by cellular factors, and intend, through determining its mechanistic basis, to be able to form the basis of a strategy to block this import pathway specifically, and thereby inhibit HIV replication. This may form the basis in the future of a new pharmaceutical approach to combat HIV-AIDS.Read moreRead less
Engineered Histones As DNA Carriers With Application In Therapeutic Gene Delivery
Funder
National Health and Medical Research Council
Funding Amount
$417,750.00
Summary
We intend to apply our knowledge of protein transport to the nucleus to enhance the delivery of DNA to target cells. This relates to the use of gene therapy to treat genetic defects such as inborn errors of metabolism, where a disease-causing lack-of-function mutation can be overcome by engineering cells within the organism which express, in the necessary quantities and in response to the appropriate regulatory signals, the particular component which is lacking. A limiting factor in gene therapy ....We intend to apply our knowledge of protein transport to the nucleus to enhance the delivery of DNA to target cells. This relates to the use of gene therapy to treat genetic defects such as inborn errors of metabolism, where a disease-causing lack-of-function mutation can be overcome by engineering cells within the organism which express, in the necessary quantities and in response to the appropriate regulatory signals, the particular component which is lacking. A limiting factor in gene therapy approaches is the low efficiency of nuclear uptake of introduced DNA, where it has been estimated that < 1% of the DNA taken up is actually expressed. Our proposal seeks to develop approaches to enhance non-viral-mediated gene delivery, in particular by optimising this critical, limiting step of the delivery of exogenous DNA to the nucleus. We intend to apply knowledge from studies of nuclear targeting and chromatin assembly to improve gene transfer technologies. We will build on our work showing that specific signals for nuclear import - nuclear targeting signals (NTSs) - can be used to enhance nuclear gene delivery and expression. Since DNA in the normal cellular context is in the form of chromatin - a specific complex with proteins such as histones - we intend to use reconstituted chromatin as the transfecting DNA, whereby histones engineered to include NTSs and other modular sequence elements will be used. Chromatin should not only enable NTSs and other sequence modules to be linked to the DNA but also protect against nuclease-mediated degradation prior to nuclear entry, condense the DNA to enable more efficient cellular-nuclear entry, and ensure expression of the transfected reporter gene by presenting it to the cell in a physiological context. Our approaches should contribute to bringing gene therapy closer to reality in the clinic.Read moreRead less
Altered Nuclear Trafficking And Nuclear Body Dynamics As Drivers Of Ataxin-1 Toxicity
Funder
National Health and Medical Research Council
Funding Amount
$755,190.00
Summary
Ataxias are a large group of neurodegenerative disorders in which balance, motor skills and memory are progressively lost. While mutations in specific proteins do cause certain hereditary ataxias, the mechanisms of their detrimental actions is unclear. Our studies probe the toxic mechanisms of the ataxin-1 protein, focusing on its partners and stress-initiated formation of a toxic hydrogel state. The outcomes will define impacts on cellular protein movement in neurodegeneration more broadly.
E-cadherin is one of the major proteins responsible for mediating cell-to-cell adhesion in the body. During development, E-cadherin is essential for establishing the cellular architecture of epithelial organs and for maintaining epithelial function in the adult. In this context, E-cadherin acts to establish and maintain the polarity of epithelial cells. E-cadherin is also a powerful tumour suppressor and the loss of E-cadherin expression or function is a primary event in metastasis and cancer in ....E-cadherin is one of the major proteins responsible for mediating cell-to-cell adhesion in the body. During development, E-cadherin is essential for establishing the cellular architecture of epithelial organs and for maintaining epithelial function in the adult. In this context, E-cadherin acts to establish and maintain the polarity of epithelial cells. E-cadherin is also a powerful tumour suppressor and the loss of E-cadherin expression or function is a primary event in metastasis and cancer invasion. Proteins at the surface of epithelial cells must be sorted and trafficked, or transported, to different membrane domains. E-cadherin, for instance, must be trafficked to the lateral domain of cells in order to function in cell-cell adhesion. We recently discovered that cell surface E-cadherin is re-internalized and recycled back to the surface via a pathway that is poised to contribute to the regulation of cell adhesion. Our proposed studies aim to reveal how newly-synthesized E-cadherin and recycling E-cadherin are trafficked, which molecules and which vesicle carriers accomplish this transport. E-cadherin has specific amino acids that act as targeting signals for its sorting and trafficking; we have recently identified one such signal and will now seek the signal responsible for its endocytosis. Using specifically engineered mutants of E-cadherin we will also study other proteins that interact with E-cadherin during its trafficking for sorting and regulation. One of these is polycystin, a protein that is mutated in a common inherited kidney disease. Insights into this disease and normal kidney epithelial function will emerge from this work. A growing understanding of E-cadherin function and regulation is essential for the health of epithelial organs and for controlling and preventing cancer.Read moreRead less
Unravelling The Binding And Activation Mechanism Of A Complex G Protein-coupled Receptor
Funder
National Health and Medical Research Council
Funding Amount
$1,041,638.00
Summary
The peptide hormone relaxin is currently in a Phase III trial for the treatment of heart failure. However the peptide is not a good drug as it can't be taken orally and is very expensive to produce. We will study the interaction of relaxin with its cell surface receptor and the mechanisms by which the receptor functions. The knowledge gained will aid in the design of smaller, more potent and orally active forms of relaxin for the treatment of heart failure
Determining Modes Of Binding And Activation Of Complex G-protein Coupled Receptor Targets
Funder
National Health and Medical Research Council
Funding Amount
$620,399.00
Summary
The peptide hormones relaxin is currently in a Phase III trial for the treatment of heart failure. However the peptide is not a good drug as it can't be taken orally and is very expensive to produce. We will study the interaction of relaxin and the related peptide INSL3 with their cell surface receptors and the mechanisms by which the receptors function. The knowledge gained will aid in the design of smaller, more potent and orally active forms of relaxin which will be able to be used as drugs f ....The peptide hormones relaxin is currently in a Phase III trial for the treatment of heart failure. However the peptide is not a good drug as it can't be taken orally and is very expensive to produce. We will study the interaction of relaxin and the related peptide INSL3 with their cell surface receptors and the mechanisms by which the receptors function. The knowledge gained will aid in the design of smaller, more potent and orally active forms of relaxin which will be able to be used as drugs for the treatment of heart failure.Read moreRead less