Cytoplasmic organization of POXvirus DNA replication.

Poxviruses, a family of large DNA viruses, are unique among DNA viruses, because they carry out DNA replication in the cytoplasm rather than the nucleus. This process does not occur randomly, but instead, these viruses create cytoplasmic 'mini-nuclei', distinct sites that are surrounded by membranes derived from the rough endoplasmic reticulum (ER) that support viral replication. This review summarizes how distinct steps preceding cytoplasmic DNA replication, as well as replication itself, operate in the host cell. The collective data point to an important role for both the rough ER and the microtubules and indicate that these cellular structures help to co-ordinate the virus life cycle to ensure that individual steps occur at the right time and place. In a broader sense, they emphasize how viruses have evolved sophisticated ways to use host cells to optimize their life cycles to ensure efficient production of infectious progeny.