( A ) Chromatin isolated from wt and Δ rap1 cells was immuno-precipitated using antibodies against RNAPII C terminal domain repeats either unmodified (αtotal) or phosphorylated at Serine 2 (αpS2) or Serine 5 (αpS5). Quantitative real-time PCR was performed using primers flanking TERRA TSS (left graph) or amplifying a fragment from the highly transcribed RNAPII substrate gene act1 (right graph; positive control). Graphs show the fraction of input DNA retrieved in the different samples, after subtraction of the background signal measured for control reactions performed using only beads. Bars and error bars are averages and standard deviations from three independent experiments. ( B ) Total proteins were extracted from wt and Δ rap1 strains and analyzed by western blot with the same antibodies used for ChIP. Act1 was used as loading control.
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