TABLE 2.
Position of septa in mid1p helix mutants
| Straina | % Misplaced septab (level of septum displacement)c at:
|
||
|---|---|---|---|
| 20°C | 30°C | 36°C | |
| Wild type | 8 (moderate) | 5 (moderate) | 5 (moderate) |
| mid1Δ mutant | ND (severe) | 98 (severe) | 99 (severe) |
| Cter-GFP | >95 (severe) | >95 (severe) | >95 (severe) |
| Helix* Cter-GFP | >95 (severe) | >95 (severe) | >95 (severe) |
| NLS* Cter-GFP | >95 (severe) | >95 (severe) | >95 (severe) |
| Helix*NLS* Cter-GFP | >95 (severe) | >95 (severe) | >95 (severe) |
| Helix* mid1-GFP | 62 (moderate) | 27 (moderate) | >95 (severe)d |
| NLS* Helix* mid1-GFP | 50 (moderate) | 33 (moderate) | 47 (moderate) |
| GFP-Nter | 49 (moderate) | 29 (moderate) | 80 (moderate) |
a
Wild-type strain, mid1Δ strain, and mid1Δ strains expressing Cter-GFP, Helix* Cter-GFP, Helix*NLS* Cter-GFP, Helix* mid1-GFP, Helix*NLS* mid1-GFP, and GFP-Nter correspond, respectively, to FC418, SP1601, AP621, AP829, AP826, AP583, AP630, and AP998 (see Table 1).
b
Percentage of misplaced septa was determined on 200 cells (two independent experiments) after septum staining with Fluostain I.
c
Septum displacement was much weaker in full-length helix mutants and GFP-Nter mutant than in mid1Δ or Cter-GFP mutants.
d
This phenoype is due to Helix* mid1-GFP instability at 36°C (see Fig. 4B).