The Smc5/6-Mms21 complex supports the anti-recombinogenic function of Sgs1.

<p>(A) Lack of the Mms21 SUMO ligase mildly compromises chromatin separation in the <i>sgs1-mn</i> background. Left column on green background: From top down: Percent of tetrads with 0, 1,2,3,4 spores containing nuclear DNA. Bottom: Spore viability from tetrad dissection. Right upper panel: Meiotic progression of <i>sgs1-mn mms21-11</i> was followed by spindle labeling. n = 200 cells, continuous line: monopolar spindles, dotted line: bipolar spindles. Right lower panel: Continuous line: cells containing one DAPI stained nucleus (1n), dotted lines: cells with 2 or 4 nuclei (2n+4n), dashed lines: cells with 4 nuclei (4n). (B) As in (A). The Mms21 SUMO ligase guarantees complete chromatin separation in the <i>zip1Δ</i> mutant indicating that the Mms21 SUMO ligase is required for full Smc5/6-Mms21 resolvase activity. Top to bottom: Percent of tetrads with 0,1,2,3,4 spores containing nuclear DNA. Number at the bottom: Spore viability from tetrad dissection given as percentage. Genotypes indicated above each column. Right upper panel: Meiotic progression of <i>zip1Δ</i> was followed by spindle labeling. n = 200 cells, continuous line: monopolar spindles, dotted line: bipolar spindles. Right lower panel: Meiotic progression of <i>zip1Δ mms21-11</i> was followed by spindle labeling. n = 200 cells, continuous line: monopolar spindles, dotted line: bipolar spindles. (C; and D) Chromosomal interaction sites and intensities are highly similar between Sgs1 and Smc6. DNA-interaction sites for Sgs1-myc18 (t = 4.5 hours in SPM) and Smc6-myc13 (t = 3.5 hours in SPM) on a 130 kb region of chromosome V. ChIP-seq signals are shown after smoothing (bandwidth: 500 bp), NCIS normalization and background subtraction as described in <a href="http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.1004067#s4" target="_blank">Materials and Methods</a>. Black: Sgs1. Smc6 signals were plotted in red on the negative scale to facilitate comparison. The obvious Sgs1/Smc6 symmetry in the example region is corroborated genome-wide by the high Pearson correlation (pcorr = 0.8) over more than 6000 peaks per profile. Yellow lollipops: DSB positions as defined in <a href="http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.1004067#pgen.1004067-Pan1" target="_blank">[53]</a> (corresponding to ∼7000 DSB-hotspots across the genome). These positions map overwhelmingly often precisely at the ChIP-seq peaks. The filled grey profile represents Mer2-HAint. (t = 4h) to illustrate core site signals. Note that smaller Sgs1 signals, and to a lesser extent also Smc6 signals also overlap with core sites, as defined by Mer2. (D) Pearson correlation coefficient matrix between the peaks of all profiles shown in this work. Matching peaks (after smoothing to a bandwidth of 300 bp and subtracting the smoothed untagged control) were identified (based on exceeding a certain threshold, set here to Q = 0.7) and their intensities compared by Pearson correlation. The coloring should facilitate comparisons: dark blue represents low correlations whereas lighter shades indicate increased correlation. Intensities between DSBs and ChIP-seq profiles do not match (p_corr<.3), whereas intensities of peaks between Sgs1 and Smc6 profiles usually highly (frequently p_corr>.75).