Figure 1.

Organization of the M. pulmonis hsd1 (Upper) and hsd2 (Lower) loci. To better illustrate features within the hsdS genes, the hsdM and hsdR genes were shortened and were not drawn to scale. Homologous regions within hsdS are shown by like shading. The sites labeled α, β, γ, and δ refer to vip DNA inversion sites. The sites labeled hrs1, hrs2, and hrs3 are additional sites for DNA inversion. The single promoter driving hsd transcription is labeled by P. The orientations of primer binding sites for PCR analysis are indicated by arrows.