TABLE 1.
Sites tested for complementation with insertion of mVenus
| Insertion site construct | Location of inserta | Function as sole FtsZ sourceb | Dominant negative effectc |
|
|---|---|---|---|---|
| Small-colony formation | No colony formation | |||
| mVenus-M1-FtsZ | Amino terminus | S | ||
| E35-mVenus-G36 | Back | N | ||
| G55-mVenus-Q56 | Back | C, G | No DN effect | — |
| G63-mVenus-I64 | Left | N | No DN effect | — |
| G71-mVenus-A72 | Top | N | No DN effect | — |
| L123-mVenus-G124 | Left bottom | N | ||
| G124-mVenus-I125 | Left bottom | N | ||
| M206-mVenus-N207 | Bottom (T7 loop) | N | 1× | 4× |
| S218-mVenus-E219 | Front | N | ||
| G221-mVenus-Y222 | Front | N | ||
| E233-mVenus-D234 | Back right | N | ||
| E250-mVenus-D251 | Front | N | ||
| D251-mVenus-I252 | Front | N | ||
| S255-mVenus-G256 | Front | N | ||
| F268-mVenus-D269 | Back | N | ||
| D288-mVenus-N289 | Front | N | 3× | — |
| D299-mVenus-P300 | Back | N | 3× | — |
| N303-mVenus-D304 | Back right | N | ||
| D304-mVenus-E305 | Back right | N | 3× | — |
| G316-mVenus-M317 | C-terminal linker | S | 5× | — |
| Q333-mVenus-P334 | C-terminal linker | S | No DN effect | — |
| A366-mVenus-K367 | C-terminal linker | S | 3× | — |
| FtsZ-D383-mVenus | Carboxyl terminus | S | ||
“Front,” “back,” “right,” and “top” refer to the subunit oriented as in a microtubule, where “front” is the outside surface and “top” is the location of GDP; see Fig. 6 for the front view.
C, full complementation (note that this means that the FtsZ construct was fully functional for colony formation; some constructs produced aberrant Z rings and longer cells, indicating defects in the Z ring that were not lethal); S, function in suppressor strains; N, did not provide complementation or generate suppressor strains; G, was successfully incorporated into the genome, replacing the genomically expressed FtsZ.
Dominant negative (DN) effects were tested for some inserts. The number indicates the expression level of mutant FtsZ compared to that of wtFtsZ within BW27783 that caused small or no colonies, as determined in a previous study (29). 3×, expression with 0.0005% arabinose; 4×, expression with 0.0015% arabinose; 5×, expression with 0.005% arabinose; no DN effect, colonies were not reduced in size at 0.005% arabinose, in which the mutant FtsZ protein was present at ∼5× the level for wtFtsZ; —, small colonies were still present at the 5× level.