Figure 1.

A Borrelia hermsii mutant lacking vmp _Ex is generated through targeted deletion. (a) Targeted deletion of vmp _Ex on B. hermsii lpE27 is depicted. Following transformation of the targeted deletion construct, pAE12, into wild‐type B. hermsii, the plasmid is integrated into lpE27 via homologous recombination at the target site (gray). The introduced replicated telomere (rtel, orange stripes) is resolved by endogenous ResT, resulting in a deletion of all downstream sequence, including the entire vmp _Ex promoter (p, arrow) and locus. The resulting lpE27 plasmid of Bh∆vmp _Ex is truncated and possesses kan ^R. Arrows depict the location of genes required for autonomous replication of lpE27. (b) DNA hybridization with an lpE27 specific probe and a kan ^R probe to wild‐type (WT) B. hermsii and Bh∆vmp _Ex plasmid DNA. Selected molecular weight standards (mws) are shown on left. (c) Surface proteolysis and immunoblot of WT B. hermsii and BhΔvmp _Ex lysates with Anti‐VmpE antibodies. Both clones were proteinase K (pk) treated (+) and untreated (−) to detect surface localization of variable major proteins (Vmp). Anti‐FlaB immunoblots served as a loading control