PCV genome arrangement and cloning scheme. A. Diagram of the linearised PCV-1 genome, depicted in the orientation cloned into pTHCapgrttnC. The rep intron is shown enlarged, and the capsid gene promoter (Pcap) is indicated. The core and Conserved Late Element (CLE) components of Pcap are shown enlarged. Abbreviations: rep = replication associated protein gene, cap = capsid protein gene, Prep = rep gene promoter, Ori = origin of replication, core = composite host transcription factor binding site. B. Schema of expression cassettes for pTH and pGL3-promoter based plasmid constructs. Whole genome and Pcap PCV-1 DNA inserts were inserted in either orientation into pTHgrttnC, pTHluc and pGL3-promoter plasmids. Plasmids were designated as Cap when whole genome PCV-1 DNA was inserted in the orientation shown in A, or as Rep when the genome was inserted in the opposite orientation. Plasmids were designated as Pcap when Pcap DNA was inserted in the orientation shown in A, or as PcapR when the Pcap fragment was inserted in the opposite orientation. The Pcap core DNA fragment and the CLE fragment (orientation independent hairpin structure) were cloned into pTHgrttnC only. Plasmids were designated as C when the Pcap core fragment was cloned in the orientation shown in A, and as CR when in the opposite orientation.