FIG 5.

YbeY affects vir gene expression and Vir protein amounts. (A) WT, Δhfq, and ΔybeY strains harboring a plasmid-carried virB-lacZ fusion were cultured under virulence inducing (+Vir) and noninducing conditions (–Vir). Under +Vir conditions, the β-galactosidase activity was reduced in the ybeY mutant, whereas deletion of hfq did not affect virB-lacZ expression significantly compared to WT activity. (B) Protein amounts of VirB2 (12.3 kDa), VirB5 (23.3 kDa), VirB8 (26.3 kDa), and VirB9 (32.2 kDa) under the conditions described for panel A were detected via Western blotting. Vir proteins were detectable only under +Vir conditions. Vir protein amounts were slightly increased in the Δhfq strain but did not show significant differences in the ΔybeY strain. GroEL (57.4 kDa) served as a loading control.