FIG. 4.

Influence of upstream IRs on dbpBA expression. B. burgdorferi dbpBA deletion mutant BbKH500 transformed with different shuttle vectors were grown in BSK-H medium and harvested at late-log phase. The expression of DbpB and DbpA were assessed using qRT-PCR (A) or immunoblot analysis (B). (A) Results from three tests are presented as the mean fold changes (relative to the gene expression level in OY45) ± SEM. (B) Approximately 4 × 10⁷ spirochetes were loaded onto each lane of an SDS-PAGE gel and transferred to a nitrocellulose membrane. FlaB, DbpB, and DbpA were detected using antibodies described in the Materials and Methods. α, anti; OY45, vector containing the minimal (Min) PdbpBA; OY50, vector containing the WT PdbpBA; OY51, vector containing ΔIR₁ PdbpBA; OY48, vector containing Δ−35 PdbpBA.