TABLE 5.
Suppression of the edm phenotype by increased expression of MMR proteinsa
| Relevant genotype | Suppression rating with plasmid used to transform each strain:
|
||||
|---|---|---|---|---|---|
| EXO1 low copy number (pRDK834) | MLH1 low copy number (pRDK835) | PMS1 high copy number (pRDK436) | POL30 low copy number (pRDK837) | POL30 high copy number (pRDK833) | |
| Wild type (RKY3590) | − | − | − | − | − |
| exo1Δ (RKY4168) | +++ | − | − | − | +++ |
| mlh1-G19D exo1Δ (RKY4170) | ++ | ND | − | ND | ND |
| mlh1-A28T exo1Δ (RKY4171) | +++ | +++ | − | ND | +++ |
| mlh1-A41T exo1Δ (RKY4172) | ++ | +++ | − | ND | + |
| mlh1-P157L exo1Δ (RKY4173) | +++ | +++ | ++ | ND | +++ |
| mlh1-T227I exo1Δ (RKY4174) | +++ | +++ | ++ | − | +++ |
| mlh1-R265K exo1Δ (RKY4175) | ++ | +++ | − | ND | +++ |
| mlh1-R547K exo1Δ (RKY4176) | ++ | +++ | ++ | − | +++ |
| pms1-A130V exo1Δ (RKY4177) | +++ | − | +++ | − | +++ |
| pms1-G160D exo1Δ (RKY4178) | ++ | − | +++ | − | +++ |
| pms1-G305S exo1Δ (RKY4179) | +++ | + | +++ | + | +++ |
| pms1-T749I exo1Δ (RKY4180) | +++ | + | +++ | − | +++ |
| pms1-D774N exo1Δ (RKY4181) | +++ | − | +++ | − | +++ |
| pms1-D901N exo1Δ (RKY4182) | + | − | +++ | ND | +++ |
| msh2-M541I exo1Δ (RKY4183) | ++ | − | ++ | − | +++ |
| msh2-S762F exo1Δ (RKY4184) | ++ | − | ND | − | +++ |
| msh3-G824R exo1Δ (RKY4185) | ++ | − | ++ | ++ | +++ |
| pol30-E143S exo1Δ (RKY4186) | +++ | − | − | +++ | +++ |
| pol32-Q46STP exo1Δ (RKY4187) | +++ | ++ | − | − | +++ |
| rnr1-G271S exo1Δ (RKY4188) | +++ | ++ | − | ++ | +++ |
a
Each of the indicated edm strains was transformed with the indicated plasmid, and the mutator phenotype was assessed in patch tests using the lys2::InsE-A10 assay as described in Materials and Methods. The values reflect a qualitative rating of the suppression observed: +++, complete suppression to wild-type reversion levels; ++, two-thirds suppression; +, one-third suppression; −, no suppression; ND, not determined. After each genotype, the strain or plasmid identification number is indicated in parentheses.