FIG. 1.

The vls locus of B. burgdorferi B31. Arrangement of the vls expression site, vlsE, and the contiguous array of 15 silent cassettes comprising the vls locus on the right telomere end of lp28-1. The six variable regions of the central vlsE cassette and the six invariant regions. The bars flanking the vlsE cassette region and silent cassettes represent the 17-bp direct repeats. The silent cassettes (vls2–16) are not drawn to scale. Arrows positioned at the beginning of vlsE and silent cassettes indicate the respective orientations. Arrows located within the intergenic region denote the inverted DNA repeat. DR, 17-bp Direct repeat; p, vlsE promoter (reprinted with permission from Springer, Copyright 2012).⁸