Figure 5.

Gross chromosomal rearrangements and cell lethality induced by G4 DNA in vid22Δ. (A) Schematic representation of the left arm of Chr V in strains used for GCR assay. The G4 or the G4-mutated cassettes were inserted at the PRB1 locus. PCM1 is the essential gene nearest to the left telomere; URA3 and CAN1 are the two genetic markers used to select for chromosome arm loss or interstitial deletions. (B) The plot represents the fold enrichment obtained with GCR experiments. The fold enrichment is the ratio of the GCR rate between vid22Δ and wild type containing the same cassette. Each data point is from an independent fluctuation test, with n ≥ 3 for each strain. The horizontal bars indicate the mean CGR rate for each strain (N = 3 independent experiments). An unpaired Student's t-test was used to compare the means of measurements and the p-value is indicated. (C) Partial sequences of the two cassettes inserted at PRB1 locus. The underlined Gs are essential for G4-DNA formation; bold Gs in G4-mutated sequence were substituted with C to abolish G4 formation. (D) Survival curve after TMPyP4 treatment. Wild-type and vid22Δ strains were treated for 2 hours with TMPyP4 at the indicated concentration and plated on YEPD. The percentage of survival was reported (N = 3 independent experiments). An unpaired Student's t-test was used to compare the means of measurements and the p-value is indicated.