Schematic presentation of pGFP::SW2 (top) [] and its derivative pGFP-CAT::SW2 (bottom). Sequence originated from the C. trachomatis SW2 plasmid is shown in red, and non-chlamydial sequences in black. Compared to pGFP::SW2, the β-lactamase gene has been removed and a Bam H1 cutting site located upstream of the GFP-CAT fusion gene has been inactivated in pGFP-CAT::SW2. All other features, including the C. trachomatis plasmid replication origin (pSW2 ori) and coding sequences (CDS) 1-8, E. coli pUC replication origin (pUC ori), the GFP-CAT fusion gene and the Neisseria meningitidis promoter (nmP) that drives the expression of GFP-CAT, remain unchanged in pGFP-CAT::SW2. See Methods for construction details.