FIGURE 1.

Poxvirus genome replication. Panel i, poxviruses have linear genomes with hairpin ends. ii, rolling hairpin replication results in genome concatemers with inverted repeats (indicated by arrows) located at the concatemer junctions. Panel iii, cruciform extrusion generates a four-way (Holliday) junction at the concatemer junction. Panel iv, the poxvirus resolvase cleaves the junction, resulting in duplex ends that contain single strand breaks (nicks). Panel v, ligation of the nicked duplex ends results in monomeric genome copies.