TABLE 2

Viability and mating-type switching efficiency of wild-type and mutant strains

% survival% switched
One nonhomologous end (MATa to MATα)
Wild type76.1 ± 3.185.7 ± 2.7
rad1Δ58.6 ± 2.1*70.6 ± 2.8*
slx4Δ57.1 ± 2.5*67.6 ± 3.9*
rad1Δ slx4Δ54.4 ± 2.2*69.3 ± 4.3*
msh2Δ67.6 ± 4.080.6 ± 2.5
msh3Δ67.9 ± 2.081.5 ± 3.0
mus81Δ72.6 ± 1.788.7 ± 5.9
pol3-0165.1 ± 5.183.2 ± 3.4
rad1Δ mus81Δ56.1 ± 3.8*74.5 ± 7.5
rad1Δ pol3-0155.6 ± 5.2*70.6 ± 3.8*
rad9Δ75.1 ± 3.182.5 ± 2.6
rad1Δ rad9Δ56.3 ± 2.7*74.7 ± 3.3
Two homologous ends (MATa to MATa)
Wild type99.7 ± 2.2NA
rad1Δ95.3 ± 4.5NA
slx4Δ93.8 ± 4.3NA
Two nonhomologous ends (MATaKANMX to MATα)
Wild type62.7 ± 3.772.8 ± 7.4
rad1Δ26.8 ± 1.2*0.8 ± 0.8*
msh2Δ23.5 ± 2.9*9.8 ± 2.3*
msh3Δ29.9 ± 1.7*10.0 ± 3.1*
rad51Δ25.2 ± 2.7*0.0 ± 0.0*
  • Percentage cell survival (induced/uninduced) was determined by examining the viability of cells plated after a 30-min induction of HO expression. Surviving cells were assayed to determine the percentage that had switched mating type from MATa to MATα as described in materials and methods. Data are presented as the mean ± SEM of at least four independent experiments. Asterisks indicate values significantly different from wild-type with P < 0.01, Students t-test. For one nonhomologous end (standard mating-type switching), nonhomologous sequence (Ya) is present on only the proximal side of the DSB. For two homologous ends, strains were induced for MATa to MATa switching; thus, “% switched” is not applicable (NA). For two nonhomologous ends, the indicated strains contain nonhomologous sequences on both sides of the DSB due to insertion of KANMX on the distal side of the break (see Figure 1B).