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A schematic 3D model of the vaccinia virion
 


We present in this web site a schematic, dynamic 3D model of vaccinia virion. The model was constructed to accompany a review of vaccinia virus structure and assembly (Condit et al., 2006). The model is not intended to be definitive in its details, especially given continuing uncertainty regarding dimensions of the virion and its substructures, but we feel that it will clarify some of the microscopic images available and the interrelationships of the virion components.

For external dimensions we have used the measurements determined by Cyrklaff et al. (2005) using cryo electron tomography, and for internal dimensions we have used the measurements determined by Hollinshead et al. (1999) from cryosections. Additional details and references pertaining to the virion structure can be found in the review (Condit et al., 2006).

The virus appears as a slightly flattened barrel with overall dimensions of approximately 360 x 270 x 250 nm. The particle is encased in an outer membrane, which itself consists of two component domains. The outermost membrane domain is 9 nm thick and the innermost membrane domain is 5 nm thick. The membrane contains a lipid bilayer, which probably corresponds to the inner membrane domain. We have not attempted to show the ridges, “surface tubule elements”, normally seen on the surface of negatively stained preparations of virus. Within the membrane is the core, which is also barrel shaped, but which contains two indentations, one on each of the largest surfaces. The core is defined by a core wall, which is also comprised of two layers, an outer, thicker, striated “palisade” layer 17 nm thick, and an inner smooth layer 8 nm thick. We have not attempted to show the striations comprising the palisade of the outer core wall. Filling the spaces between the core wall and the membrane that are created by the indentations in the core are “lateral bodies”. Within the core is a tube-like structure, 50 nm in diameter with a 10 nm diameter core. This tube is folded upon itself into three continuous segments, with a total length of approximately 250 nm.


References:

Condit, R. C., Moussatche, N., Traktman, P., (2006). In a nutshell: structure and assembly of the vaccinia virion. Adv.Virus Res. 66: 31-124.
Cyrklaff, M., Risco, C., Fernandez, J. J., Jimenez, M. V., Esteban, M., Baumeister, W., Carrascosa, J. L., (2005). Cryo-electron tomography of vaccinia virus. Proc.Natl.Acad.Sci.U.S.A 102, 2772-2777.
Hollinshead, M., Vanderplasschen, A., Smith, G. L., Vaux, D. J., (1999). Vaccinia virus intracellular mature virions contain only one lipid membrane. J.Virol. 73, 1503-1517.