title: Human cytosolic extracts stabilize the HIV-1 core.
abstract: The stability of the HIV-1 core in the cytoplasm is crucial for productive HIV-1 infection. Mutations that stabilize or destabilize the core showed defects on HIV-1 reverse transcription and infection. We developed a novel and simple assay to measure the stability of in vitro-assembled HIV-1 CA-NC complexes. The assay allowed us to demonstrate that cytosolic extracts strongly stabilize the HIV-1 core. Interestingly, stabilization of in vitro-assembled HIV-1 CA-NC complexes is not due solely to macromolecular crowding, suggesting the presence of specific cellular factors that stabilize the HIV-1 core. By using our novel assay, we measured the abilities of different drugs, such as PF74, CAP-1, IXN-053, cyclosporine, Bi2 (also known as BI-2), and the peptide CAI, to modulate the stability of in vitro-assembled HIV-1 CA-NC complexes. Interestingly, we found that PF74 and Bi2 strongly stabilized HIV-1 CA-NC complexes. On the other hand, the peptide CAI destabilized HIV-1 CA-NC complexes. We also found that purified cyclophilin A destabilizes in vitro-assembled HIV-1 CA-NC complexes in the presence of cellular extracts in a cyclosporine-sensitive manner. In agreement with previous observations using the fate-of-the-capsid assay, we also demonstrated the ability of recombinant CPSF6 to stabilize HIV-1 CA-NC complexes. Overall, our findings suggested that cellular extracts specifically stabilize the HIV-1 core. We believe that our assay can be a powerful tool to assess HIV-1 core stability in vitro.
authors.affiliation: Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York, USA.
authors.forename: Thomas
authors.initials: T
authors.lastname: Fricke
authors.forename: Alberto
authors.initials: A
authors.lastname: Brandariz-Nuñez
authors.forename: Xiaozhao
authors.initials: X
authors.lastname: Wang
authors.forename: Amos B
authors.initials: AB
authors.lastname: Smith
authors.forename: Felipe
authors.initials: F
authors.lastname: Diaz-Griffero
mesh_terms: D015153:Blotting, Western; D002213:Capsid / Q000378:metabolism*; D016572:Cyclosporine / Q000494:pharmacology; D003600:Cytosol / Q000378:metabolism*; D015658:HIV Infections / Q000378:metabolism / Q000517:prevention & control* / Q000821:virology; D015497:HIV-1 / Q000502:physiology*; D006801:Humans; D007166:Immunosuppressive Agents / Q000494:pharmacology; D016297:Mutagenesis, Site-Directed; D009154:Mutation / Q000235:genetics; D019251:Nucleocapsid / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D010446:Peptide Fragments / Q000494:pharmacology*; D014771:Virion / Q000472:pathogenicity; D019065:Virus Assembly; D054301:gag Gene Products, Human Immunodeficiency Virus / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism
chemical_list: D007166:Immunosuppressive Agents; D010446:Peptide Fragments; D054301:gag Gene Products, Human Immunodeficiency Virus; D016572:Cyclosporine