Fig. 2. Construction of linear plasmid integrants and predicted structure of telomere resolution products. (A) An E.coli plasmid (pKK81) carrying bp 1424–3315 from the left end of lp17 was used in a B.burgdorferi transformation to generate a plasmid integrant in lp17 via homologous recombin ation. (B) A linear plasmid integrant was constructed as in (A), but with an E.coli plasmid (pGCL10-2) that also carried the 140 bp replicated left-end telomere of lp17 corresponding to the L′–L junction (Figure 1). DNA breakage and reunion in the replicated telomere are expected to give rise to the two linear molecules shown; only the larger plasmid would contain the gene for kanamycin resistance (kan). Although the diagram has been drawn with homologous recombination preceding telomere resolution, a specific temporal order of events is not implied; telomere resolution of the transforming DNA followed by homologous recombination would yield the same set of final products. Blue denotes the kan gene, yellow represents the E.coli plasmid vector and green the lp17 sequences used for the recombination target. White indicates other lp17 sequences and red denotes telomeric regions. Probes 1 and 2 indicate the regions used as hybridization probes in Figure 3. The schematic is not drawn to scale.