Lau D, Márquez CL, Parker MW, Böcking AT. Negative Staining
Transmission Electron Microscopy of HIV Viral Particles Permeabilized with PFO and Capsid Stabilized with IP6.
Bio Protoc 2022;
12:e4536. [PMID:
36353716 PMCID:
PMC9606454 DOI:
10.21769/bioprotoc.4536]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Revised: 08/21/2022] [Accepted: 09/12/2022] [Indexed: 12/29/2022] Open
Abstract
The human immunodeficiency virus 1 (HIV-1) consists of a viral membrane surrounding the conical capsid. The capsid is a protein container assembled from approximately 1,500 copies of the viral capsid protein (CA), functioning as a reaction and transport chamber for the viral genome after cell entry. Transmission electron microscopy (TEM) is a widely used technique for characterizing the ultrastructure of isolated viral capsids after removal of the viral membrane, which otherwise hinders negative staining of structures inside the viral particle for TEM. Here, we provide a protocol to permeabilize the membrane of HIV-1 particles using a pore-forming toxin for negative staining of capsids, which are stabilized with inositol hexakisphosphate to prevent premature capsid disassembly. This approach revealed the pleomorphic nature of capsids with a partially intact membrane surrounding them. The permeabilization strategy using pore-forming toxins can be readily applied to visualize the internal architecture of other enveloped viruses using TEM. Graphical abstract.
Collapse