Table II.
Phenotypic characterization of ncr1 mutant strains
| Genotypes
|
|||||
|---|---|---|---|---|---|
| Phenotypes tested |
NCR1
(normal) |
ncr1 Δ | Y718D | Y718N | Y571C |
| Sterol synthesis ([3H]acetate), (P vs. NCR1) |
18.2 ± 2.9 | 19.7 ± 1.2 (0.4) |
13.2 ± 2.3 (0.07) |
13.2 ± 1.8 (0.07) |
16.2 ± 1.6 (0.37) |
| Sterol esterification ([3H]oleate), (P vs. NCR1) |
11.0 ± 2.8 | 11.9 ± 2.4 (>0.05) |
11.9 ± 0.9 (>0.05) |
10.5 ± 2.7 (>0.05) |
10.7 ± 1.7 (>0.05) |
| Exogenous sterol esterification [14C]cholesterol, (P vs. NCR1) |
74.3 ± 2.0 | 69.2 ± 6.3 (>0.05) |
72.2 ± 3.8 (>0.05) |
77.9 ± 3.6 (>0.05) |
78.1 ± 0.8 (>0.05) |
| 30°C (2% dextrose) | ++ | ++ | + | ++ | ++ |
| 38°C (2% dextrose) | ++ | ++ | – | ++ | ++ |
| Anaerobiosis | ++ | ++ | + | ++ | ++ |
| Nystatin (5 μg/ml) | ++ | ++ | – | ++ | ++ |
| Ethanol (3%) | ++ | ++ | – | ++ | ++ |
| Acetate (2%) | ++ | ++ | – | ++ | ++ |
| Sodium chloride (0.75 M) | ++ | ++ | – | ++ | ++ |
| Sorbitol (1.0 M) | ++ | ++ | + | ++ | ++ |
| Calcium chloride (0.8 M) | ++ | ++ | + | ++ | ++ |
| Hydroxyurea (40 mM) | ++ | ++ | + | ++ | ++ |
Yeast strains with the missense mutations Y718D, Y718N, and Y571C in the SSD of NCR (Fig. 1 B) were assessed for growth or metabolic incorporation (percent incorporation ± SEM) under the conditions described. The growth of the normal strain is considered ++ and the growth of the other strains is expressed relative to that scale.