The HIV-1 Tat Protein Is An Reverse Transcription Co-factor.
Funder
National Health and Medical Research Council
Funding Amount
$404,592.00
Summary
HIV-1 is the virus that causes AIDS. In order for HIV-1 to grow, the viral genetic material must be converted into a form that is compatible with a human host. Specifically, the HIV-1 genetic material is made of RNA while the human genome is composed of DNA. An HIV-1 enzyme called reverse transcriptase (RT) is used for this purpose. We have discovered that another HIV-1 protein called Tat is also required for the efficient conversion of HIV-1 RNA into HIV-1 DNA. If HIV-1 lacks Tat, then this tra ....HIV-1 is the virus that causes AIDS. In order for HIV-1 to grow, the viral genetic material must be converted into a form that is compatible with a human host. Specifically, the HIV-1 genetic material is made of RNA while the human genome is composed of DNA. An HIV-1 enzyme called reverse transcriptase (RT) is used for this purpose. We have discovered that another HIV-1 protein called Tat is also required for the efficient conversion of HIV-1 RNA into HIV-1 DNA. If HIV-1 lacks Tat, then this transformation process is inefficient and HIV-1 is not able to grow. Recently our group made a breakthrough discovery on how Tat works. Tat can directly bind to RT and stimulate the conversion process. This research is aimed at a detailed analysis of Tat and RT interaction. This information is required in order to understand how this interaction can be blocked in order to stop HIV-1 growth. In the long-term, results produced by this research will be required to discover novel drugs to combat HIV-AIDS.Read moreRead less
Elucidating The Activation Mechanism Of The HIV-1 Envelope Glycoproteins, Gp120-gp41
Funder
National Health and Medical Research Council
Funding Amount
$636,973.00
Summary
Antiretrovirals prolong the life of HIV+ people, however toxicity and resistance issues persist. We aim to understand how the HIV surface proteins effect viral entry in order to identify new antiviral targets.
Studies On The Activation And Immunogenicity Of The HIV-1 Glycoproteins, Gp120-gp41
Funder
National Health and Medical Research Council
Funding Amount
$606,438.00
Summary
More than 34 million people were living with HIV-1 in 2011 with ~7,000 new infections still occurring daily. A prophylactic vaccine for HIV-1 is needed to stop its transmission, however, this goal is yet to be achieved. Our proposed studies will inform the design of prophylactic HIV-1 vaccines that act by making antibodies that neutralize the virus.
Pathogenesis Of Persistent Human Virus Infections Of Global Significance
Funder
National Health and Medical Research Council
Funding Amount
$6,571,328.00
Summary
The study will investigate why humans cannot eradicate particular viruses (HIV-AIDS, cytomegalovirus and herpes simplex virus), the long term effects of these viruses and ways to improve control. Current treatments can only partly suppress the levels of these viruses, because they persist in certain parts of the body called reservoirs, only to resurge later causing disease. Thus, the overall aim of the research program is to discover the mechanisms by which these viruses are able to successfully ....The study will investigate why humans cannot eradicate particular viruses (HIV-AIDS, cytomegalovirus and herpes simplex virus), the long term effects of these viruses and ways to improve control. Current treatments can only partly suppress the levels of these viruses, because they persist in certain parts of the body called reservoirs, only to resurge later causing disease. Thus, the overall aim of the research program is to discover the mechanisms by which these viruses are able to successfully persist within reservoirs in the human body. The research program brings together a group of 6 leading scientists and clinicians located at 3 sites in 2 Australian cities. The team is comprised of experts in the study of HIV-AIDS, cytomegalovirus and herpes simplex virus who will combine their knowledge and expertise to speed up the process of research on these viruses that are of major health importance. Studies will also utilise a number of cutting edge technologies that now make it possible to much more rapidly and precisely determine how viruses cause disease. Advances in our understanding of how viruses persist may form the basis for treatments aimed at controlling persistent infections and the serious diseases caused by these viruses.Read moreRead less
The diversity of HIV quasispecies within a single AIDS patient is far greater than the global diversity of influeneza annually, highlighting the enormous burden HIV imposes on the immune network. The capacity of HIV-1 to evolve quickly has significantly impaired our effort to produce effective vaccine and long lasting treatment strategy. This project utilizes multidisciplinary approaches to delineate determinants that drives the diversification of HIV-1.
Control Of Viral Replication By Non-coding Viral RNA
Funder
National Health and Medical Research Council
Funding Amount
$502,270.00
Summary
In 25 years since identified, HIV-AIDS deaths have exceeded 30 million and 40 million more are now living with HIV. The toll will soon far surpass any other infectious disease epidemic in history, or even military deaths from war in the past century. While effective combination drug therapies are available, multi-drug resistant HIV strains are commonly transmitted, leaving some patients with limited treatment options. New classes of drugs aimed at different steps in virus replication are urgentl ....In 25 years since identified, HIV-AIDS deaths have exceeded 30 million and 40 million more are now living with HIV. The toll will soon far surpass any other infectious disease epidemic in history, or even military deaths from war in the past century. While effective combination drug therapies are available, multi-drug resistant HIV strains are commonly transmitted, leaving some patients with limited treatment options. New classes of drugs aimed at different steps in virus replication are urgently needed. We have discovered that viral RNAs that do not code for protein serve important functions in HIV replication. We will study the molecular mechanisms these non-coding (intron) RNAs previously considered junk use to support of HIV gene expression and assess their potential as drug targets. First, we will investigate the role of these junk RNA loops, or lariat introns, produced in large amounts during the HIV replication cycle. Retroviruses employ RNA splicing to make mRNA for envelope and regulatory accessory genes. The complex alternative RNA splicing pattern of HIV spawns several non-coding lariats, including the lariat-intron that contains much of the removed env coding sequence. We have made the counterintuitive finding that the env-lariat dramatically enhances expression of Env protein. We will examine how this occurs and the involvement of the new class of gene-expression controlling micro-RNAs in this process. We will test for functional activity from the other lariat-introns that are produced by HIV. Second, we will characterise the mRNA-element required for efficient expression of the HIV envelope glycoprotein, Env gp160, which is essential for virus binding and entry during infection. This RNA-element directs the cell protein translation machinery to commence protein synthesis at the start of the Envgp160 rather than at upstream start sites for Vpu and Rev. We will determine how this RNA element works, its structure, and how it might be inactivated.Read moreRead less
HIV infection is a dynamic process, in which the host immune response tries to control viral growth and keep up with the rapid evolution of the virus. This project assembles an interdisciplinary team of mathematicians and biologists to use a modelling approach to understand the dynamics of viral infection, viral evolution, and immune control in the infected individual. The insights gained from this project will help in the development of new drug and vaccination strategies.
Drug Resistance Mutations In The Connection Subdomain Of The HIV-1 Reverse Transcriptase
Funder
National Health and Medical Research Council
Funding Amount
$376,710.00
Summary
Human immunodeficiency virus type 1 (HIV-1) infections can be controlled with antiretroviral drugs. In the majority of patients on antiretroviral therapy the virus mutates and is no longer inhibited by the drug. The emergence of drug-resistant HIV-1 is one of the major factors that lead to loss of drug efficacy in patients. Mutations that confer drug resistance have been defined and are specific for different drug classes. Genotype assays that are used to predict drug resistance are routinely us ....Human immunodeficiency virus type 1 (HIV-1) infections can be controlled with antiretroviral drugs. In the majority of patients on antiretroviral therapy the virus mutates and is no longer inhibited by the drug. The emergence of drug-resistant HIV-1 is one of the major factors that lead to loss of drug efficacy in patients. Mutations that confer drug resistance have been defined and are specific for different drug classes. Genotype assays that are used to predict drug resistance are routinely used to guide therapeutic decisions in the treatment of HIV-1 infected individuals. For drugs that target the HIV-1 reverse transcriptase (RT), commonly used genotype kits normally analyse mutations in the first 240 out of 560 amino acids of the reverse transcriptase. This ignores the impact of mutations in other regions of the enzyme, which are potentially important in drug resistance. Recently, mutations that inhibit ribonuclease H function of the HIV-1 RT have been shown to confer high-level resistance to zidovudine, providing the precendent that mutations beyond codon 240 can confer drug resistance. Our analysis of a different region to ribonuclease H called the connection subdomain has demonstrated the presence of mutations that are highly prevalent in drug-treated versus drug naive patients. In this study we will use in vitro assays to define the effect of these mutations on drug resistance and viral fitness . We will also determine the mechanism by which these mutations confer drug resistance. Finally, using our unique database consisting of over 20,000 genotyped samples , we will establish the role of these mutations in the patient. This study is anticipated to identify clinically significant mutations that are present in the RT connection subdomain. Additionally, this study will lead to the development of more accurate genotype assays which will improve the clinical management of HIV infected individuals.Read moreRead less