FIG 6.

Localization of TolQ and TolA in the absence of FtsN and other Tol-Pal proteins. GFP fluorescence (left) and DIC (right) images of CH238 (Δ[tolQ-cpoB] ftsB^E56A) (A, C, and F) or CH239 (Δ[tolQ-cpoB] ftsB^E56A ΔftsN] (all other panels) cells carrying either plasmid pCH516 (P_lac::tolQ-gfp) (A, B), or lysogenic for λNP4 (P_lac::gfp-tolA) (C to E) or λCH549 (P_lac::gfp-malF^2-39 -tolA^47-292) (F to H). The cells in panels E and H additionally carried plasmid pMG20 (P_BAD::^TTbfp-ftsN^71-105), encoding a periplasmic fusion containing the essential domain of FtsN (^EFtsN). Cells were grown for ∼3.5 mass doublings to OD₆₀₀ = 0.5 to 0.6 in M9-maltose medium with 5 μM (A and B) or 37 μM (C to H) IPTG and with 0.1% (E and H) or no (all others) arabinose, and imaged live. Bar equals 2 μm. Note that both full-length TolA (D) and the TolAII domain (G) fail to accumulate at division sites in the complete absence of FtsN and actually appear to be partially excluded from such sites in some of the cells (arrowheads).