Requirement of Rap1 on chromosome truncation at TG repeats.

<p>(A) Effect of <i>rap1</i>-degron mutation on colony formation in the presence of CuSO₄. Wild-type or <i>rap1</i>-degron mutant (<i>rap1-(Δ)</i>) cells were serially diluted (10-fold) and spotted on medium containing 0, 0.05 or 0.5 mM CuSO₄. (B) Effect of CuSO₄ concentration on Rap1-(Δ) protein expression. Wild-type or <i>rap1-(Δ)</i> cells were initially grown in the absence of CuSO₄ and then incubated with the indicated concentrations of CuSO₄ for 6 hr. Aliquots of cells were collected and subjected to immunoblotting analysis with anti-Rap1 antibodies. (C) Effect of Rap1 depletion on <i>URA3</i>^<i>Kl</i> marker loss. Wild-type or <i>rap1-(Δ)</i> cells containing the TG₂₅₀ cassette were first maintained in medium selective for <i>URA3</i> and then transferred to non-selective medium containing 0.05 mM CuSO₄. Saturated cultures were diluted and spread on 5-FOA plates to determine the rate of <i>URA3</i>^<i>Kl</i> marker loss. <i>URA3</i>^<i>Kl</i> maker loss was determined as in <a href="http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.1005283#pgen.1005283.g001" target="_blank">Fig 1C</a>.