[Proteomic Analyses of Purified Particles of the Rabies Virus]

The rabies virus (RABV) is an enveloped RNA virus. It mainly damages the central nervous system and causes anencephaly in mammals and humans. There is now compelling evidence that enveloped virions released from infected cells can carry many host proteins, some of which may play an important part in viral replication. Several host proteins have been reported to be incorporated into RABV particles. However, a systematic study to reveal the proteomics of RABV particles has not been conducted. In the present study, after virus culture and purification by sucrose density gradient ultracentrifugation, a proteomics approach was used to analyze the protein composition of purified RABV particles to understand the molecular mechanisms of virus-cell interactions. Fifty host proteins, along with five virus-encoded structural proteins, were identified in purified RABV particles. These proteins could be classified into ten categories according to function: intracellular trafficking (14%), molecular chaperone (12%), cytoskeletal (24%), signal transduction (8%), transcription regulation (12%), calcium ion-binding (6%), enzyme binding (6%), metabolic process (2%), ubiquitin (2%) and other (14%). Of these, four proteins (beta-actin, p-tubulin, Cofilin, Hsc70) were validated by western blotting to be present in purified RABV particles. This novel study of the composition of host proteins in RABV particles may aid investigation of the mechanism of RABV replication.