Inverted repeat and GAA/TTC-induced DSB detection in wild-type and mutant strains.

<p>Upper panel depicts the relative positions of the inverted repeats and the probe (open rectangle) used. For the detection of inverted repeat-mediated breaks <i>Δsae2</i> strains were used as in these mutants the hairpin-capped breaks are not opened and resection is abolished <a href="http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.1003551#pgen.1003551-Lobachev1" target="_blank">[21]</a>. As a consequence, inverted dimer molecules accumulate in <i>Δsae2</i> mutants as previously demonstrated. Contour-clamped homogeneous electric field gel electrophoresis and Southern hybridization were used to highlight the intact chromosome V and the broken fragment. Lanes 1, 2 and 3 depict the <i>Alu-</i>IR, <i>pol3-P664L Alu-</i>IR, and <i>IS50-</i>IR strains respectively. Lanes 4 and 5 depict GAA/TTC₍₂₃₀₎ and TET-<i>POL3</i> GAA/TTC₍₂₃₀₎ strains respectively. Intact chromosome V, DSB fragments and inverted dimers (in the case of inverted repeats) are indicated.