Fig. 6. Conversion of a circular plasmid to a linear form. (A) Schematic showing the shuttle vector without (pBSV2) or with (pGCL40-5) the 140 bp replicated telomere (L′–L) inserted into the polylinker (solid line). The circular plasmid pGCL40-5 is expected to be converted to a linear form if telomere resolution occurs. (B) Southern blot of a 0.7% agarose gel containing total B.burgdorferi plasmid DNA from strain B31-A transformed with the circular shuttle vector (pBSV2) or the shuttle vector carrying the replicated telomere (pGCL40-5). DNA samples were run before and after digestion with NcoI. Five times more DNA was used for the pGCL40-5 transformant because of the 5-fold reduction in copy number. The blot was hybridized with a probe made from the backbone (pOZK) of the shuttle vector (Stewart et al., 2001). The migration positions of the supercoiled, linear and relaxed forms of pBSV2 are denoted by S, L and R, respectively. The migration positions of 1.68 and 4.73 kb markers (not shown) are noted on the right side of the figure.