Susanne Tonnemacher (Langen / DE), Regina Eberle (Langen / DE), Renate Kunz (Ulm / DE), Paul Walther (Ulm / DE), Jacomina Krijnse Locker (Langen / DE)
Abstract text (incl. figure legends and references)
Introduction: Enveloped viruses acquire their membrane from the host, but for the large DNA-virus vaccinia virus (VACV), member of the poxviridae, the origin and biogenesis of its membrane remains controversial until this date.
By electron microscopy (EM) newly synthesized VACV membranes appear as short, half-moon shaped units (the crescents) that grow into membrane spheres, the immature virus (IV). Upon DNA-uptake, the IV matures in to the infectious brick-shaped mature virus (MV) [1]. The gene product of A6, a 43 kDa protein, is one of five VACV proteins that seem to be required for viral membrane biogenesis and the formation of infectious virus, collectively called virus membrane associated proteins (VMAPs) [2].
Objectives: It is known, that the VMAPs play an essential role in the assembly of the VACV. In this study, the role of A6 in VACV-assembly was further investigated.
Materials & methods: Hela cells were infected with a recombinant VACV where the synthesis of A6 can be conditionally induced. Cells infected with or without A6 synthesis were fixed at different time points and prepared for EM-imaging. Complementary EM-imaging methods were applied: conventional thin section EM, EM-immuno-labeling and scanning transmission electron tomography.
Results: When the expression of A6 is blocked, IV- and MV-formation is absent [3]. Instead aberrant virally induced structures accumulate in a time dependent manner; fragmented core accumulations, and large spherical membranes, resembling IVs, but devoid of viral core proteins.
Conclusion: It seems that A6 plays a role in the interaction of core protein and crescents.
Reference: [1] DOI: 10.1016/j.virol.2015.02.003
[2] DOI: 10.1128/JVI.02405-16
[3] DOI: 10.1128/JVI.00877-09