around the division site would iteratively build
the invaginating septum.
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We thank F. Gueiros-Filho, R. Losick, M. Erb, and P. Levin for strains;
J. Xiao for discussions; L. Lavis for Janelia Fluor dyes; B. Murphy and
E. Pasciak for FDAA synthesis help; F. Gueiros-Filho, R. Daniel, and
J. Errington for antibodies; R. Losick, B. LaSarre, and D. Kearns for
comments. This work was supported by NIH grants GM113172 to M.S.V.
and Y.V.B., GM51986 to Y.V. B., and DP2AI117923-01 to E. C.G.; a
Newcastle University Research Fellowship and Royal Society Research
Grant RG150475 to S.H.; a Science Without Borders Research Fellowship
to A. W.B.-F.; a European Research Council Advanced Grant (SynDiv
669598) to C.D.; and an NSF Graduate Research Fellowship Program
(DGE1144152) to G. R. S. SIM was performed in the Indiana University
Light Microscopy Imaging Center supported by S10RR028697-01. E. K.,
Y.V.B., and M.S.V. are inventors on U.S. Patent Application 14/395,815
(PC T Patent Application PCT/US2013/037504), submitted by the
Indiana University Research and Technology Corporation, that covers the
use of FDAAs for labeling of bacterial cell walls. Data are available in the
text and supplementary materials. Movies S1 to S10 are also available
at http://garnerlab.fas.harvard.edu/FtsZ/. Code is available at https://
Materials and Methods
Figs. S1 to S7
Tables S1 to S4
Movies S1 to S10
26 September 2016; accepted 20 January 2017
Fig. 4. Cytokinesis is controlled by directional motion of FtsAZ filaments.
(A) FtsZ(D213A) overexpression (1 mM IPTG in bAB217) produces slowly growing
FtsA spirals with spiral FDAA insertion. (Top) Montage of growing FtsA spiral acquired
with spinning-disk confocal imaging. (Bottom) Sequential FDAA labeling and FtsA
localization imaged with 3D-SIM in a fixed cell. (B) Altering FtsZ velocity changes the
amount and total area of FDAA incorporation. (Left) PY79 with 1 mg/ml PC190723
for 10 min, (center) bAB217 with 20 mM IPTG for 1 hour, (right) AH93 with 50 mM
xylose for 5 min. After treatment, cells were incubated with TADA for the indicated
time, fixed, then imaged with 3D-SIM. (Far right) Total intensity and area of septal
FDAA incorporation. Lines, mean. **P < 0.01; ***P < 0.001; ****P < 0.0001. (C)
Cytokinesis scales with FtsZ treadmilling velocity. For each condition, pairs of strains
were used to measure (i) FtsZ velocity (using mNeonGreen-FtsZ) and (ii) septation
rates (using mNeonGreen-Pbp2B). (Top) Kymographs of constricting Pbp2B rings
in different FtsZ backgrounds (dashed line marks start of constriction). (Bottom)
Plot of constriction time versus FtsZ velocity under different conditions. Treadmilling
velocity and septation rates were acquired in identical conditions, save for mea-
surements with MciZ (see supplementary materials). Error bars, SD of the mean.
(A), (B), and (C): Scale bars, 0.5 mm. Dashed line in (C, bottom), slope. (D) Model
for treadmilling-coupled cell division. (Top) The Z ring contains multiple FtsAZ
filaments that treadmill around the division plane, pulling associated PG synthases.
(Bottom) FtsZ treadmilling both regulates and distributes the activity of the PG
synthases, building sequentially smaller uniform arcs of PG to divide the cell.
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