Molecular determinants of virus-like nanoparticle assembly in vitro and in animal cell culture

Protein nanoparticles, such as virus-like particles (VLPs), consist only of the virus shell without any viral genetic information packaged inside. Similarly to viruses, the structural proteins that comprise a VLP can spontaneously self-assemble to form the particle or can assemble through several intermediate steps. This work addresses the characterization, manipulation and purification of a chimeric simian-human immunodeficiency VLP constructed by fusion of SIV matrix protein (p17) and HIV-1 p6 accessory protein. This fusion protein assembles as spherical nanoparticles of about 80 nm in diameter that are released to the culture media when expressed in HEK 293T cells. A simple two-step purification process was used to purify these nanoparticles. Also, different approaches - multiple-transfections or chemical coupling - were performed to target manipulation. Finally, a new approach for the production of these virus-like particles is described where the structural protein subunits are used and their assembly is promoted in vitro.