Joint Appointment in Biochemistry and Biophysics
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Viruses are remarkably plastic entities. New strains evolve constantly driven by genetic drift and iterative mutagenesis. Acceleration of these evolutionary processes in a laboratory setting will greatly impact our ability to carry out studies focused on understanding molecular mechanisms underlying viral infection. The overarching goal of my lab is to combine the tools and principles of molecular biology and genetics with chemistry to generate a synthetic viral toolkit. The resulting hybrid viral entities are utilized to unravel viral infectious pathways, provide novel vectors for gene therapy and reagents for molecular genetics applications. We work in close collaboration with several other labs within the UNC Gene Therapy Center towards achieving these goals.
The Adeno-Associated Virus (AAV) Capsid
AAV is a non-pathogenic member of the Parvoviridae family that is rapidly gaining popularity as a vector for gene transfer. Among the smallest known viruses at a diameter of 25nm, the icosahedral AAV shell is comprised of 60 protein subunits and encapsidates a single-stranded DNA genome. We are interested in understanding the biology of the AAV capsid at the molecular level. For instance, how does the capsid self-assemble? How do changes in amino acid residues result in capsids with altered tissue tropism? To answer these questions, we utilize an ever-expanding synthetic AAV toolkit generated through a combination of rational and combinatorial mutagenesis as well as new tools at the interface of chemistry and molecular biology.
The Lentiviral Envelope
The Lentivirus (e.g., HIV), a genus of the Retroviridae family, is another popular tool for gene transfer applications. The spherical virions are enveloped with lipids derived from host cell membranes and package an RNA genome. Using metabolic engineering tools, we are interested in manipulating molecular components of the lentiviral envelope to generate a synthetic lentiviral panel for mechanistic studies and gene therapy applications.
The Viral Genome
Manipulation of genomic material packaged within viruses is critical towards vector development for gene therapy applications. Towards this end, we are interested in (a) incorporation of novel regulatory elements in viral vector genomes, (b) identification and mechanistic characterization of small molecules that impact viral gene expression and (c) exploring the possibility whether viruses can package chemically altered genomes.
We use non-pathogenic AAV and Lentiviral vectors as our primary virus models. The synthetic strategies utilized in our lab can be extrapolated to other viruses as well. Within this framework, we are constantly seeking interesting questions that warrant re-engineering any viral component with chemical biology tools to understand its role in the viral life cycle.
simulations, as well as their grafting into a host protein (used in protein design)
- Glycan binding avidity determines the systemic fate of adeno-associated virus 9 Shen S, Bryant K, Sun J, Brown S, Troupes A, Pulicherla N, Asokan A.
- Tyrosine Cross-Linking Reveals Interfacial Dynamics in Adeno-Associated Viral Capsids during Infection. Horowitz ED, Finn MG, Asokan A. ACS Chem Biol. 2012 Apr 6.
- Intra- and inter-subunit disulfide bond formation is nonessential in adeno-associated viral capsids. Pulicherla N, Kota P, Dokholyan NV, Asokan A. PLoS One. 2012;7(2):e32163. Epub 2012 Feb 28.
- The AAV vector toolkit: poised at the clinical crossroads. Asokan A, Schaffer DV, Samulski RJ. Mol Ther. 2012 Apr;20(4):699-708.
Gene Therapy Center
5123A Thurston Bowles
Campus Box # 7352
Chapel Hill, NC 27599-7264
Office: (919) 843-7621
Lab: (919) 843-7622