Head of Division
Professor Christopher Burrell
HIV/AIDS Head of Laboratory
Dr Peng Li
Senior Laboratory Staff
Dr Jillian Carr
Dr Adam Davis
Research Staff
John Karlis
Carl Coolen
Adrian Purins
PhD Students
Kelly Cheney
Feng Feng
Jennifer Clarke
Satiya Wati
Adrian Purins
Honours Student
Sarah Martin
Interests
HIV
HTLV-1
Dengue Virus
Physical Setting
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First floor, north wing of the IMVS, ring 8222 3574 for access
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Three PC2 facilities
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One PC3 laboratory (secured, negative pressure laboratory specifically for handling infectious agents such as HIV
Contacts
For information regarding potential PhD or Honours candidatures within the HIV/AIDS Research Laboratory, contact:
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Dr Peng Li peng.li@imvs.sa.gov.au 8222 3544
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Dr Jill Carr jill.carr@imvs.sa.gov.au 8222 3574
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Dr Adam Davis adam.davis@imvs.sa.gov.au 8222 3574
Background & Laboratory Aims
Acquired Immunodeficiency Syndrome (AIDS) and Human Immunodeficiency Virus (HIV) infection are global health issues that have been a major threat to both Western and third world cultures for nearly 20 years. Recent statistics from the World Health Organisation indicate that 40 million people are currently HIV positive. There is currently no effective vaccine and while anti-retroviral therapy has been enormously successful in assisting HIV positive people, therapies can not eradicate HIV from patients and the inevitable emergence of drug resistant virus remains a major problem. Current therapy requires that patients take drugs for the rest of their life, thus side effects of the anti-retroviral drugs and compliance are long-term issues in HIV medicine.
HIV
is a complex retrovirus whose life cycle involves infection of target cells,
reverse transcription and permanent integration into the host genome (figure
1). While AIDS is characterised by T-cell depletion, 
target
cells for HIV include CD4+ T-cells, cells of the monocyte/macrophage
lineage, and a variety of other cells, and active HIV replication can be found
in the circulation and at tissue sites such as lymph nodes and the brain.
In general our laboratory aims are to investigate the basic mechanisms of HIV-1
replication in target cells. More specifically we are interested in the early
post-entry events of viral replication such as reverse transcription and viral
integration. Understanding these events may lead to insights relevant to viral
pathogenesis and applicable to anti-viral drug design.
Current Laboratory Projects
Virion Infectivity Factor (Vif)
The HIV accessory protein, Vif, has recently been under intense scrutiny. It is essential for efficient replication in natural target cells of the body, but is dispensable in some immortalised cell lines. Investigation of this phenomenon lead to the discovery of an innate anti-viral mechanism, by which the host cell damages the replicating HIV genome in newly infected target cells. The prototype host enzyme involved is APOBEC-3G, although other members of the APOBEC enzyme family may also play a role and the anti-viral effect may be broadly applicable to viruses other than HIV. The HIV Vif protein negates this anti-viral pathway (reviewed in 1). Thus, investigations of the mechanism by which Vif acts to overcome host cell defences and other potential actions to enhance viral infectivity are of extreme interest. We have two on-going projects related to Vif function.
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Interaction of Vif with ZIN
Work of Feng Feng and Adam Davis have characterised an interaction of Vif with the cellular protein ZIN (5). Further characterisation of the biological relevance of this interaction is currently underway.
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Virion infectivity factor (Vif) and reverse transcription complexes
Although the major effect of Vif is believed to be in producer cells, Vif is also incorporated into virus particles. Jill Carr and Carl Coolen have demonstrated that Vif is also carried over into newly infected target cells and retained as part of reverse transcription complexes (RTC’s, 4), large protein/nucleic acid complexes that are the active site of HIV reverse transcription. The function of Vif in RTC’s is currently under investigation. This project is closely linked to the following projects investigating the process of reverse transcription.
Reverse Transcription
Reverse Transcription is an essential early step of viral replication. Many anti-virals target this early step and aim to prevent the irreversible incorporation of HIV into the host cell genome. Reverse transcription is carried out by the reverse transcriptase (RT) enzyme, encode by HIV, while part of a large complex, the RTC. We have a long term interest in the constituents and regulators of the RTC which are not yet fully understood (2). Upon viral infection, the incoming RTC becomes activated and reverse transcription ensues. We believe that phosphorylation of RTC components plays a critical part in this activation process.
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Activation of Reverse Transcription by phosphorylation
This project is investigating post-translational modifications of RT at early time points following HIV infection. Adam Davis has identified the presence of different isoforms of RT which change as infection progresses.
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The role of phosphorylation in HIV-1 reverse transcriptase activity
The isoforms of RT identified above are potentially due to changes in protein phosphorylation. Sarah Martin, an honours student, in conjunction with Adam Davis has made targeted mutants in potential RT phosphorylation sites and is currently investigating replication of the mutant viruses.
Clinically Related Projects
Although the focus of our research laboratory is on the basic mechanisms of viral replication, clinically related projects are of more direct relevance to the patient community. Through links with our diagnostic arm of IDL, the RAH clinic and with the kind co-operation of HIV positive patients, we are investigating several more applied lines of research.
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HIV-1 in CD4-CD8- T cells from patients on anti-retroviral therapy
Kelly Cheney has been investigating the potential of a particular type of T cell (CD8-CD4-) to act as a reservoir for latent integrated HIV that cannot be accessed by current anti-retroviral regimes. This is of relevance to the potential for complete eradication of HIV from the body.
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Integrated viral load in clinical samples
Routine patient management currently involves analysis of circulating virus and CD4+ T-cell levels. Jill Carr, Kelly Cheney and Carl Coolen are adapting our laboratory method for quantitation of integrated HIV genomes (10, 11) to measurement in clinical samples.
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Investigation of anti-viral effects of traditional Chinese medicines
Using in vitro laboratory replication models Adam Davis and John Karlis are investigating the potential of extracts derived from Chinese medicines to act as anti-viral compounds, particularly targeting at or prior to viral integration.
Other Projects
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HIV-1 infection of astrocytes
Jen Clarke has described a novel mechanism for cells of the brain (astrocytes) to become non-productively infected with HIV yet harbour virus that can be potentially transmitted to other brain cells.
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Characterisation of HTLV-I infection/replication
Our laboratory also has an interest in another retrovirus, HTLV-I (3). This virus has the potential to cause leukaemia and possesses a novel replication strategy, which is being investigated by Adrian Purins.
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Dengue virus infection of macrophages
In addition to retroviruses we have on-going projects with dengue virus (DV). DV is a Flavivirus of major significance in tropical and sub-tropical areas of the world and is capable of causing serious clinical infection and mortality. Previous work by Jill Carr and co-workers has investigated infection in monocyte-derived macrophages (MDM) and its relevance to endothelial cell function (6, 14). Currently, Satiya Wati is further investigating control of DV replication in MDM and the host cell responses to infection.
References
Navarro, F and Landau, N.R. (2004) Recent insights into HIV-1 vif. Current Opinion in Immunology. 16(4) : 477-482
Karageorgos, L., P. Li, and C. Burrell. (1993). Characterization of HIV replication complexes early after cell-to-cell infection. AIDS Research & Human Retroviruses 9,817-823.
Benovic, S., Kok, T.W., Stephenson, A., McInnes, J.L., Burrell, C. and Li, P. (1998). De novo reverse transcription of HTLV-I following cell-to-cell transmission of infection. Virology, 244, 294-301.
Laboratory Publications (last 5 years)
Carr, J. M., Davis, A. J., Coolen, C., Burrell, C. J. and Li, P. (2004) Human immunodeficiency virus 1 (HIV-1) virion infectivity factor (vif) is part of reverse transcription complexes. Journal of General Virology (submitted)
Feng, F., Davis, A., Lake, J., Carr, J., Xia, W., Burrell, C. and Li, P. (2004) Ring finger protein ZIN interacts with human immunodeficiency virus type 1 Vif. Journal of Virology 78: 10574-81
Carr, J. M., Hocking, H., Bunting, K., Wright, P. J., Davidson, A., Gamble, J., Burrell, C. J. and Li, P (2003) Supernatants from Dengue virus type-2 infected macrophages induce permeability changes in endothelial cell monolayers. Journal of Medical Virology 69: 521-528
Adamson, C.S., Davis, A., Soneoka, Y., Nemut, M., Mitrophanous, K. and Jones, I.M (2003). A block in virus-like particle maturation following assembly of murine leukaemia virus in insect cells. Virology 314(2): 488-496
Lake, J., Carr, J., Feng, F., Mundy, L., Burrell, C. & Li, P.(2003) The role of Vif during HIV-1 infection: interactions with novel host cellular factors. Journal of Clinical Virology. 26: 143-152
Matthias, L., Yam, P., Jiang, X., Vandegraaff, N., Li, P., Poumbourios, P., Donogue, N. & Hogg, P. (2002) Disulfide exchange in domain 2 of CD4 is required for entry of HIV-1. Nature Immunology 3: 727-732.
Kumar, R., Vandegraaff, N., Mundy, L., Burrell, C., & Li, P. (2002) Evaluation of PCR-based methods for quantification of integrated HIV-1 DNA. Journal of Virological Methods. 105: 233-246.
Vandegraaff, N., Kumar, R., Burrell, C. J., & Li, P. (2001) Kinetics of HIV-1 DNA integration in acutely infected cells using a novel assay for the detection of integrated HIV DNA. Journal of Virology. 75:11253-11260.
Carr, J.M., Calvert, J.K., Kumar, R., Burrell, C.J. & Li, P. (2001) Effects of deletion and the site of insertion in double copy anti-tat retroviral vectors: Viral titres and production of anti-tat mRNA. Archives of Virology. 146:2191-2200.
Kok, T., Li, P. & Burrell, C.J. (2001) HIV DNA integration during cell-to-cell transmission of infection: Evidence for partially integrated DNA structures in acutely infected cells. Archives of Virology. 146:1963-1978.
Pryor, M.J., Carr, J.M., Hocking, H., Davidson, A.D., Li, P. & Wright, P.J. (2001) Replication of dengue virus type 2 in human monocyte-derived macrophages: comparison of isolates and recombinant viruses with substitutions at amino acid 390 in the envelope glycoprotein. American Journal of Tropical Medicine and Hygiene. 65: 427- 434
Vandegraaff, N., Kumar, R., Hocking, H., Burke, T. R., Mills, J., Rhodes, D., Burrell, C. J., & Li, P. (2001) Specific inhibition of human immunodeficiency virus type 1 (HIV-1) integration in cell culture: Putative Inhibitors of HIV integrase. Antimicrobial Agents & Chemotherapy. 45: 2510-2516.
Carr, J., Hocking, H. Li, P. & Burrell, C.J.(1999) Rapid and efficient cell-to-cell transmission of human immunodeficiency virus infection from monocyte-derived macrophages to peripheral blood lymphocytes. Virology 265: 319-329.
Ey, P.L., Freeman, N. L., Bela, B., Haese, P. M., Li, P. & McInnes, J. L. (1999) Sequence and comparative structural analysis of the murine leukaemia virus amphotropic strain 4070A RNase H domain. Archives of Virology. 144: 2185-2199.
Campbell, D.G. & Li, P. (1999) Sterilization of HIV with irradiation: Relevance to infected bone allografts. Aust. N.Z. J. Surg. 69: 517-521.
Peng, H., Callison, D., Li, P. & Burrell, C.J. (1999) Interference between effector RNAs expressed from conventional dual-function anti-HIV retroviral vectors can be circumvented using dual-effector cassette retroviral vectors. Human Gene Therapy. 10: 449-462.