35 Translational Control in Poxvirus-infected Cells

Abstract

As might be expected, regulation of gene expression occurs at many levels in poxvirus-infected cells. Regulation of the translational machinery primarily involves control of the double-stranded (ds) RNA-activated regulators of translation, PKR and the 2′, 5′ oligoadenylate system; the selective translation of viral mRNA in some cells; and the selective inhibition of host protein synthesis. These aspects of translational control of gene expression in poxvirus-infected cells are covered in this chapter.

THE POXVIRIDAE: A BRIEF OVERVIEW
Classification and replication of poxviruses has been reviewed recently (Fields et al. 1996). The poxviridae family is made up of large viruses with a (ds)DNA genome 130–300 kbp in length. Poxviral genomes code for more than 100 polypeptides, with the central portion coding for proteins required for virus replication, and the termini coding for proteins involved in virus/host interactions. The family is subdivided into the chordopoxviridae and entomopoxviridae, which infect chordates and arthropods, respectively. The chordopoxviridae are separated into eight recognized genera, based on morphology, antigenic cross-reactivity, and host range. The largest genus is the orthopoxviruses, which contains closely related viruses infecting buffalo, camel, monkey, mouse (ectromelia), rabbit, raccoon, vole, cattle, and humans (smallpox). Vaccinia virus, the type virus of the orthopoxviruses, is the virus that was used to immunize against smallpox in the 20th century. Whereas the original virus used for smallpox “vaccination” by Jenner was derived from a poxvirus that infected cattle (the terms vaccinia and vaccination come from the Latin, vacca, for cow), the virus we now call vaccinia virus...