Vesicular Release of Ebola Virus Matrix Protein VP40

Abstract

We have analysed the expression and cellular localisation of the matrix protein VP40 from Ebola virus. Full-length VP40 and an N-terminal truncated construct missing the first 31 residues [VP40(31-326)] both locate to the plasma membrane of 293T cells when expressed transiently, while a C-terminal truncation of residues 213 to 326 [VP40(31-212)] shows only expression in the cytoplasm, when analysed by indirect immunofluorescence and plasma membrane preparations. In addition, we find that full-length VP40 [VP40(1-326)] and VP40(31-326) are both released into the cell culture supernatant and float up in sucrose gradients. The efficiency of their release, however, is dependent on the presence of the N-terminal 31 residues. VP40 that is released into the supernatant is resistant to trypsin digestion, a finding that is consistent with the formation of viruslike particles detected by electron microscopy. Together, these results provide strong evidence that Ebola virus VP40 is sufficient for virus assembly and budding from the plasma membrane.

Analysis of Ebola virus and VLP release using an immunocapture assay

“…Although VP40 alone can drive the formation of filamentous VLPs that are released from cells (Timmins et al, 2001), our data clearly demonstrate that optimal VLP formation and release requires additional viral proteins, which is consistent with a recent report (Licata et al, 2004). These findings indicate that VP40 may be recruiting NP to the site of budding.…”

“…One model is based on the ability of VP40 and GP of EBOV (Bavari et al, 2002;Jasenosky et al, 2001;Panchal et al, 2003;Timmins et al, 2001) and Marburg (Swenson et al, 2004) to spontaneously form filamentous virus-like particles (VLPs). Striking morphological similarity of VLPs to the authentic virus (Bavari et al, 2002;Swenson et al, 2004;Timmins et al, 2001;Warfield et al, 2004a) suggests that the process of VLP formation probably closely resembles that of the live virus, making this system an ideal model for studying filoviral assembly and release.…”

Inhibition of Ebola virus glycoprotein-mediated cytotoxicity by targeting its transmembrane domain and cholesterol

“…Ebola virions are filamentous in shape, and the matrix protein VP40 and GP are sufficient to produce protrusions at the plasma membrane of adherent cells 33,34 . The protrusions resulting from VP40 are virus like, whereas the structures resulting from GP alone appear pleiomorphic 35,36 . The combination of VP40 and GP is sufficient to produce filamentous virus-like particles that exhibit the morphology of Ebola virions 37,38 .…”

Requirements for Budding of Paramyxovirus Simian Virus 5 Virus-Like Particles

“…Recombinant viruses that lack M proteins have been constructed in the cases of both rabies (27) and measles (4), and in both cases budding was drastically impaired. Furthermore, VLP release has been observed from cells transfected with plasmids encoding M proteins derived from vesicular stomatitis virus (VSV) (16,21,23), Ebola virus (15,47), influenza A virus (13,22), and human parainfluenza virus type 1 (hPIV-1) (5). VLP budding has been examined quantitatively for both VSV (21) and Ebola virus (47), and in both cases budding was remarkably efficient, with Ͼ20% of the M protein released from transfected cells into the culture medium.…”