Table 1.

Median frequencies of spontaneous mutations and DNA slippage events in msh2Δ, msh3Δ, and msh6Δstrains bearing the msh2-GD693 and msh6-GD987alleles on GAL10 2μm plasmidsa

Relevant genotypeFrequency
Canavanine resistance assayPoly(GT) tract alteration assay
Median (10−6)Relative to wtMedian (10−4)Relative to wt
msh2Δ 434411833
msh6Δ 15156.51.8
msh6Δ, vector2819NTNT
msh6Δ,pGAL10-MSH2 1812NTNT
msh6Δ,pGAL10-MSH6 6.74.4NTNT
msh6Δ,pGAL10-msh2-GD693 2617NTNT
msh6Δ,pGAL10-msh6-GD987 5738NTNT
msh3Δ 1.61.65916
msh3Δ, vector1.61.6NTNT
msh3Δ,pGAL10-MSH2 3.82.5NTNT
msh3Δ,pGAL10-MSH6 4.22.8NTNT
msh3Δ,pGAL10-msh2-GD693 5235NTNT
msh3Δ,pGAL10-msh6-GD987 3725NTNT
  • a Wild-type (wt; FY23),msh2Δ (EAY252), msh3Δ (EAY420), andmsh6Δ (EAY337) strains were transformed individually with pEAE51 (pGAL10-MSH6), pEAE20 (pGAL10-MSH2), pEAE27 (pGAL10-msh2-GD693), and pEAE84 (pGAL10-msh6-GD987) and tested for forward mutations to Canr. Vector refers to control plasmids that lackedMSH2 or MSH6 sequences. Strains were also transformed with pEAA69 [(GT)16-URA3 ARS CEN] and, where indicated, tested in the poly(GT) tract alteration assay described in Materials and Methods. The median frequency was determined from 11 independent colonies for each experiment. The averages of 2 to 10 independent experiments are presented. NT, not tested.