Figure 2. Plasmid map of the C. trachomatis/E. coli transposon-transposase shuttle vector pSW2-mCh-C9 showing the essential features for plasmid selection and transposition.

The key coding sequences (CDS) and their direction of transcription are represented by the boxes and arrows in the outer circle. The spectinomycin resistance gene ( aadA) for selection of plasmid transformants is coloured purple. The β-lactamase gene ( bla) is yellow and flanked by the repeat sequences defining the limits of the transposon (pink). The C9 transposase gene (orange) is under inducible control of the tet promoter: the tetracycline repressor gene ( TetR) is coloured magenta. E. coli transformants bearing this plasmid fluoresce red under UV illumination due to the constitutive expression of mCherry (red). The inner circle is a scale bar with 1kb increments, chlamydial plasmid sequences are blue, vector sequences are black and the transposon unit is pink.