RbmA is critical to rugose colony formation, and the expression of vpsA and vpsL is not altered in RΔrbmA. Panel A shows the colony morphologies of the rugose variant (A1), smooth variant (A2), RΔrbmA (A3), SΔrbmA (A4), RΔrbmA/pACYC177 (A5), and RΔrbmA/prbmA (A6). (B) Expression of the vpsA-lacZ and vpsL-lacZ fusion genes (carried in the pCC11 and pCC12 plasmids, respectively) in the wild-type rugose and RΔrbmA variants grown in LB at 30°C to mid-exponential growth phase (OD600 = 0.4). Error bars represent standard deviations.