Development and analysis of efficient and target-specific antiretroviral recombinases

• Applicant: Professor Dr. Frank Buchholz
• Subject Area: General Genetics and Functional Genome Biology ; Virology ; Cell Biology
• Term: from 2014 to 2018
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 260115349

Current drugs against HIV can suppress the progression to AIDS but cannot cure the infection. Because of the severe side effects of these drugs and frequently developing drug resistance, finding a cure for HIV infection remains a high priority of AIDS research and our motivation for the here proposed project. How can we shift from treatment to cure? Can we develop a cure that is applicable to the majority of all HIV-1 infected patients despite the extensive genetic variability of the virus? Site-specific recombinases are able to effectively and specifically remove DNA segments from the genome of living systems and have become widely used tools in genomic engineering of multicellular organisms. We have recently generated a recombinase (termed Tre) tailored to specifically recombine a sequence that is present in the long terminal repeat (LTR) of an HIV-1 isolate. Because the integrated HIV-1 provirus is flanked by LTRs, expression of Tre recombinase leads to the excision of the provirus from the host genome and thereby cures the cells from the infection. However, the fact that the current Tre recombinase recognises a particular HIV-1 subtype A strain may limit its broad therapeutic application. To advance our Tre-based strategy toward a universally efficient cure, we have been working on generating a new recombinase (uTre) applicable to the majority of HIV-1 infections of the various strains and subtypes. To develop uTre for future clinical use we here propose to investigate the specificity and the applied properties of the enzyme in mammalian cells and in mice. Furthermore we seek to understand better the features that influence recombinase efficiency and specificity by conducting comprehensive evolutionary, structural and modelling studies. With the gained knowledge we predict to learn general features of directed evolution that will substantially accelerate not only the development of future recombinases, but also other proteins. These findings will be directly applied to develop a novel recombinase targeting HTLV-1, another human pathogenic retrovirus.

• DFG Programme: Research Grants