Project Details
Description
Structure and function of the HIV RNA genome.
The HIV RNA genome encodes multiple highly structured motifs, such as the TAR element, the polyA hairpin, the splice-donor site and the packaging signal in the untranslated leader region. We study the role of these RNA structures in the viral replication cycle, the underlying mechanism and the proteins involved. These studies recently resulted in the identification of a microRNA that is encoded by the TAR hairpin structure and that may control viral replication through the RNA interference pathway.
Conditional-live HIV vaccine.
Live-attenuated virus vaccines have been successful against a variety of viral pathogens. However, safety concerns remain for its application against HIV in humans since the attenuated vaccine strain may revert over time to a virulent and pathogenic phenotype. As a novel approach to improve the safety of a live-attenuated HIV vaccine, we constructed a conditionally replicating virus. This virus has adopted the components of the Tet-On gene expression system for transcriptional control and replication can be switched on and off at will by the administration or removal of doxycycline. The concept is that upon vaccination in the presence of doxycycline, the virus will replicate and induce immune and other host responses. Subsequent withdrawal of doxycycline will switch off viral replication and prevent evolution to a pathogenic virus, while the induced responses will protect the vaccinee against infection with wild-type HIV. To study the efficacy and safety of this conditional-live virus vaccine approach, we constructed a similar simian immunodeficiency virus (SIV) variant that is tested in macaques. These studies also aim to identify the host responses that correlate with
protection, which is essential for the development of an effective HIV vaccine. Moreover, the novel HIV and SIV variants are attractive tools to study HIV and SIV biology. For example, we use these viruses to study the function of the virus-encoded Tat protein and TAR RNA hairpin.
Viral evolution as a tool to develop novel Tet-On gene expression systems.
Technology for the regulation of gene expression is essential for both biological/biomedical research and applications in medicine and biotechnology. The most widely used regulatory circuit is the so-called Tet-On system, which is based on the E. coli tetracycline-repressor and doxycycline as effector molecule. This Tet-On system was used to construct the conditional-live HIV variant. Spontaneous evolution of this virus in long-term cultures selected for improved variants in which the introduced bacterium-derived Tet-On system is optimized for its function in mammalian cells. These novel Tet-On systems will be very useful in biological applications that require a more sensitive or active regulatory system. We use a similar virus evolution approach to develop novel Tet-On systems that are controlled by different effectors and that will allow the independent control of multiple genes.
This research group participates in CINIMA.
The HIV RNA genome encodes multiple highly structured motifs, such as the TAR element, the polyA hairpin, the splice-donor site and the packaging signal in the untranslated leader region. We study the role of these RNA structures in the viral replication cycle, the underlying mechanism and the proteins involved. These studies recently resulted in the identification of a microRNA that is encoded by the TAR hairpin structure and that may control viral replication through the RNA interference pathway.
Conditional-live HIV vaccine.
Live-attenuated virus vaccines have been successful against a variety of viral pathogens. However, safety concerns remain for its application against HIV in humans since the attenuated vaccine strain may revert over time to a virulent and pathogenic phenotype. As a novel approach to improve the safety of a live-attenuated HIV vaccine, we constructed a conditionally replicating virus. This virus has adopted the components of the Tet-On gene expression system for transcriptional control and replication can be switched on and off at will by the administration or removal of doxycycline. The concept is that upon vaccination in the presence of doxycycline, the virus will replicate and induce immune and other host responses. Subsequent withdrawal of doxycycline will switch off viral replication and prevent evolution to a pathogenic virus, while the induced responses will protect the vaccinee against infection with wild-type HIV. To study the efficacy and safety of this conditional-live virus vaccine approach, we constructed a similar simian immunodeficiency virus (SIV) variant that is tested in macaques. These studies also aim to identify the host responses that correlate with
protection, which is essential for the development of an effective HIV vaccine. Moreover, the novel HIV and SIV variants are attractive tools to study HIV and SIV biology. For example, we use these viruses to study the function of the virus-encoded Tat protein and TAR RNA hairpin.
Viral evolution as a tool to develop novel Tet-On gene expression systems.
Technology for the regulation of gene expression is essential for both biological/biomedical research and applications in medicine and biotechnology. The most widely used regulatory circuit is the so-called Tet-On system, which is based on the E. coli tetracycline-repressor and doxycycline as effector molecule. This Tet-On system was used to construct the conditional-live HIV variant. Spontaneous evolution of this virus in long-term cultures selected for improved variants in which the introduced bacterium-derived Tet-On system is optimized for its function in mammalian cells. These novel Tet-On systems will be very useful in biological applications that require a more sensitive or active regulatory system. We use a similar virus evolution approach to develop novel Tet-On systems that are controlled by different effectors and that will allow the independent control of multiple genes.
This research group participates in CINIMA.
| Status | Active |
|---|---|
| Effective start/end date | 1/01/2008 → … |