Deletion of Mediator tail module triad subunits increases levels of polyA⁺ Ty1i RNA and p22-Gag.

<p>(A) Northern blot probed for Ty1, Ty1i and <i>PYK1</i> RNA, the latter as a loading control that has been shown not to be altered in <i>med2Δ</i>, <i>med3Δ</i>, or <i>med15Δ</i> yeast [<a href="http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.1007232#pgen.1007232.ref057" target="_blank">57</a>, <a href="http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.1007232#pgen.1007232.ref060" target="_blank">60</a>]. Quantifications of Ty1 and Ty1i RNA relative to <i>PYK1</i> RNA are averages of three biological replicates and are normalized to WT levels. (B) Pol II occupancy averaged over all 31 genomic Ty1 elements in wild type and <i>med3Δ med15Δ</i> yeast using ChIP-seq data from [<a href="http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.1007232#pgen.1007232.ref061" target="_blank">61</a>]. Ty1 elements begin at 0 kb on the x-axis, and the Ty1 TSS at +238 and Ty1i TSS at +1000 are marked by green bars on the x-axis. (C) Western blot of total cell lysate measuring levels of p22- and p18-Gag relative to the loading control, GAPDH. Quantitation, shown on a log scale, is the average ratio of p22-Gag or p18-Gag to GAPDH signal from three biological replicates of each strain. In panels (A) and (C), quantitation was performed on RNA or protein samples from the WT strain and congenic <i>spt3Δ</i> strain as a negative control (grey bars), Mediator head subunit gene deletion strains (red bars), middle subunit gene deletion strains (blue bars) and tail subunit gene deletion strains (yellow bars). All error bars represent s.d.