Fig. 2. Overexpression of flgG resulted in longer distal rods.
To test the FlgG intrinsic model for length control of the distal rod, flgG was overexpressed from a plasmid vector to supplement flgG expression from its native chromosomal locus in a strain lacking the genes required for termination of distal rod assembly (flgH) and subsequent hook assembly (flgD and flgE). (A) Flagellar basal bodies were purified from the flgG-overexpression background and compared with those from an empty-vector control strain by transmission electron microscopy (TEM). (B) Measurements were taken from the top of the MS-ring [dashed line in (A)] to the tip of the rod (P, proximal rod; D, distal rod). Overexpression of flgG was found to significantly increase the length of the rod (P < 0.0001, Student’s two-tailed t test, N = 2).