Figure 4.

Numerous technical advances, including the ability to label and visualize viral genes and gene products, combined with sophisticated imaging techniques, have yielded unprecedented insights into the details of viral replication, including the impact of coinfection with more than one virus. Studies of interactions between viruses in coinfected hosts are likely to uncover important new strategies for viral commensalism and parasitism. Live covisualization of competing adeno-associated virus (AAV) and herpes simplex virus type 1 (HSV-1) DNA replication. Replicating AAV DNA containing lac operator sequences was visualized by binding of a red fluorescent protein fused to lac repressor protein (red), while the replication of HSV-1 DNA containing tetracycline operator sequences was visualized by binding of enhanced yellow fluorescent protein fused to the tetracycline repressor DNA binding domain (green). AAV and HSV-1 DNA replication occurred in spatially separate nuclear compartments, which were often found in juxtaposition. Blue, Hoechst stain; scale in micrometers. (This figure first appeared on the cover of the Journal of Virology, May 2007, vol. 81, no. 9. [See related article on p. 4732.])