There are two major types of infectious vaccinia virus particles: mature virions (MVs) and enveloped virions (EVs). The MVs, which consist of a DNA-protein core surrounded by a lipoprotein membrane, are assembled in cytoplasmic viral factories and contain about 80 polypeptides. A subpopulation of MVs is wrapped by modified trans-Golgi or endosomal cisterna containing additional viral membrane proteins, transported along microtubules to the cell periphery, and exits the cell through the plasma membrane. The EVs are essentially MVs with an additional membrane that is disrupted prior to fusion of the MV with the cell during entry. One of the most challenging questions is how the initial viral membrane of the immature virion is formed. Using biochemical, genetic and microscopic approaches, we have obtained evidence that the endoplasmic reticulum is the source of the viral membrane and have identified several viral proteins involved in this process.

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Erlandson, Karl J; Cotter, Catherine A; Charity, James C et al. (2014) Duplication of the A17L Locus of Vaccinia Virus Provides an Alternate Route to Rifampin Resistance. J Virol :
Maruri-Avidal, Liliana; Weisberg, Andrea S; Moss, Bernard (2013) Association of the vaccinia virus a11 protein with the endoplasmic reticulum and crescent precursors of immature virions. J Virol 87:10195-206
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Satheshkumar, P S; Weisberg, Andrea; Moss, Bernard (2009) Vaccinia virus H7 protein contributes to the formation of crescent membrane precursors of immature virions. J Virol 83:8439-50
Howard, Amanda R; Senkevich, Tatiana G; Moss, Bernard (2008) Vaccinia virus A26 and A27 proteins form a stable complex tethered to mature virions by association with the A17 transmembrane protein. J Virol 82:12384-91