Retroviral Recombination, RNA Dimers & Multiple Drug Resistant HIV-1
Funder
National Health and Medical Research Council
Funding Amount
$405,017.00
Summary
The emergence of multiple drug resistant strains of HIV-1 has threatened the continue success of current clinical treatment to suppress virus propagation. Retroviruses, such as HIV-1, can reshuffle its two copies of genetic materials during the viral replication process, which leads to the production of offspring viruses that contain a mixture of the parental genetic materials. This process of genetic information reshuffling is believed to be important for the generation of multiple drug resista ....The emergence of multiple drug resistant strains of HIV-1 has threatened the continue success of current clinical treatment to suppress virus propagation. Retroviruses, such as HIV-1, can reshuffle its two copies of genetic materials during the viral replication process, which leads to the production of offspring viruses that contain a mixture of the parental genetic materials. This process of genetic information reshuffling is believed to be important for the generation of multiple drug resistant strains of HIV-1. The objective of this proposal is to define the parameters that regulate the reshuffling of HIV-1 genetic materials and to design novel tools to inhibit the production of multiple drug resistant HIV-1.Read moreRead less
During reverse transcription, the positive-strand HIV-1 RNA genome is converted into a double-stranded DNA copy which can be permanently insert into the host cell genome. Our laboratory and others have shown that reverse transcription requires a complex array of molecules, which includes the viral RNA. These RNA can be organised into elaborate structures that have only been partially defined. Genetic experiments have revealed that one of these RNA structures, called TAR, is required for optimal ....During reverse transcription, the positive-strand HIV-1 RNA genome is converted into a double-stranded DNA copy which can be permanently insert into the host cell genome. Our laboratory and others have shown that reverse transcription requires a complex array of molecules, which includes the viral RNA. These RNA can be organised into elaborate structures that have only been partially defined. Genetic experiments have revealed that one of these RNA structures, called TAR, is required for optimal initiation of reverse transcription (the first step of reverse transcription), but the precise mechanism is unknown. Recent advances in our laboratory have enabled a comprehensive study of the role played by TAR RNA in reverse transcription. Our leading hypotheses regarding the mechanism is required that TAR interacts with other RNA sequences or Reverse transcriptase in the initiation complex so that the reaction is optimal. This proposal will investigate these two leading hypotheses. Given the enormity of the HIV pandemic and the many recent reports from the United States that most patient isolated virus is resistant to at least one antiretroviral drug, these studies have as an outcome the identification and characterisation of important new key molecules towards which antiretroviral strategies can be designed.Read moreRead less
Both human and viral genetic materials (ribonucleic acids, RNA) are made up of 4 different basic residues, namely A, U, G and C. Combination of any three of these ribonucleic acids residues is known as codon , which is essential to target one of the twenty amino acids to the host cell machinery for the making of proteins. Eighteen out of these twenty amino acids can be represented by more than one codon during the making of proteins. Interestingly, human and viral proteins, such as HIV-1, utilis ....Both human and viral genetic materials (ribonucleic acids, RNA) are made up of 4 different basic residues, namely A, U, G and C. Combination of any three of these ribonucleic acids residues is known as codon , which is essential to target one of the twenty amino acids to the host cell machinery for the making of proteins. Eighteen out of these twenty amino acids can be represented by more than one codon during the making of proteins. Interestingly, human and viral proteins, such as HIV-1, utilise two completely different subsets of codons (codon bias) for the synthesis of their respective proteins. The objective of this proposal is to delineate the functional requirement of this codon bias in HIV-1 replication cycle. Results from this work will identify novel elements that may be used for the design of novel antiretroviral strategy. Furthermore, lesson learned from this project will also provide important clues to improve the efficacy and safety of the design of current retroviral gene delivery vector.Read moreRead less
A Study Of The Molecular Epidemiology And Virulence Determinants Of Enterovirus 71 Strains From The Asia-Pacific Region
Funder
National Health and Medical Research Council
Funding Amount
$286,325.00
Summary
In this study, we aim to understand the reasons for the emergence of epidemics of severe neurological disease due to enterovirus 71 (EV71) in young children of the Asia-Pacific region since 1997, and to develop strategies for disease prevention. EV71 is a human enterovirus closely related to the polioviruses. Most infections with EV71 are trivial, however, they may occasionally result in severe disease, including brainstem encephalitis with a high mortality and acute flaccid paralysis similar to ....In this study, we aim to understand the reasons for the emergence of epidemics of severe neurological disease due to enterovirus 71 (EV71) in young children of the Asia-Pacific region since 1997, and to develop strategies for disease prevention. EV71 is a human enterovirus closely related to the polioviruses. Most infections with EV71 are trivial, however, they may occasionally result in severe disease, including brainstem encephalitis with a high mortality and acute flaccid paralysis similar to poliomyelitis. There has been a large increase in EV71 epidemic activity throughout the Asia-Pacific region since 1997, including a large epidemic in Perth, Western Australia in 1999. These epidemics have resulted in many deaths and cases of severe neurological disability. In view of the severity of EV71 neurological disease and the lack of effective treatments, our research effort needs to focus on prevention through public health surveillance and vaccine development. The major aims of our study are two-fold: 1. To study the origin and evolution of EV71 in the Asia-Pacific region using molecular techniques and to use this information to implement surveillance in Australia and Southeast Asia. It is anticipated that improved surveillance will provide early warning of impending epidemics. 2. To understand the molecular basis of virulence of EV71, with emphasis on the ability of virus to cause severe disease of the central nervous system. This study will have two goals: a. To identify the human cellular receptor of EV71. The ultimate goal of this research will be the development of a small animal model of EV71 encephalitis by constructing a transgenic mouse expressing the human cellular receptor for EV71. b. To construct an infectious cDNA clone of EV71 and to develop genetically defined attenuated strains by mutagenesis of the infectious clone. Mutant strains of EV71 will be tested for replication and virulence in newborn mice and in human neuroblastoma cells.Read moreRead less
Molecular Characterization Of Human Caliciviruses Causing Gastroenteritis
Funder
National Health and Medical Research Council
Funding Amount
$173,380.00
Summary
A common cause of outbreaks of vomiting and diarrhoea in the community are small viruses approximately 30 nm in diameter. During outbreaks of such viral gastroenteritis, large numbers of people may become ill. The viruses may be transmitted in contaminated food or drink, or passed from person to person. Outbreaks have been associated with hospital wards, nursing homes, school camps, cruise ships and airline flights. The viruses causing these outbreaks are human caliciviruses. They have a structu ....A common cause of outbreaks of vomiting and diarrhoea in the community are small viruses approximately 30 nm in diameter. During outbreaks of such viral gastroenteritis, large numbers of people may become ill. The viruses may be transmitted in contaminated food or drink, or passed from person to person. Outbreaks have been associated with hospital wards, nursing homes, school camps, cruise ships and airline flights. The viruses causing these outbreaks are human caliciviruses. They have a structural resemblance to the rabbit virus recently released in Australia, but possess an alternative host range, and they produce different symptoms in the infected host. The human caliciviruses are difficult to study in the laboratory. They do not replicate in cell culture systems and no animal is known to show symptoms of infection. In this project, the techniques of genetic engineering are being used to develop diagnostic reagents for the viruses, and to study the functions of the proteins encoded by the viral genes. In the longer term, it may be feasible to develop vaccines and drugs against these viruses, but first it is necessary to discover how many types are circulating world-wide and in Australia, and to identify potential targets for antiviral drugs during virus replication.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
An Alternate Function Of The MicroRNA Biogenesis Machinery
Funder
National Health and Medical Research Council
Funding Amount
$302,981.00
Summary
Controlling the activity of genes is crucial. Too much or too little can result in a cell not functioning properly. We have discovered a new way genes are controlled. We have found that an enzyme called Drosha can prevent too much activation of some genes by chopping up the products of these genes. This way of controlling genes appears to be especially important for developmental processes, such as occurs in the embryo. Our goal is to understand this mechanism precisely at the molecular level.
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