clf-29 and tfl2-2 show coordinated H3K27me3 change profiles distinct from those in atring1a,b and atbmi1a,b.

K-means clustering of M values characterizing the quantitative change of H3K27me3 in PcG mutants. Definition of H3K27me3 quantitative change regions were based on combined criteria |M|>1 and P value <1e-3. Green and red colors represent lower and higher H3K27me3 levels in PcG mutants compared to that in Col-0. IGV screenshots support CLF and LHP1 participate in H3K27me3 elongation. Grey areas represent regions where significant H3K27me3 reductions happen mainly in surrounding regions but not in summit regions in tfl2-2 and clf-29 compared to Col-0. It’s worth noting that no smooth should be applied while preparing data for IGV screenshots, or else the difference between Col and clf-29 or tfl-2 would not be as obvious as the raw data. (C) Visualization of the profile of average read intensity around peak summits. All regions from peak set I were aligned such that peak summit is in the center of each region. Next, average read intensities were calculated and plotted for each consecutive 50 bp. (D) The diagram illustrates the finding based on H3K27me3 ChIP-seq data comparisons that LHP1 and CLF participate in elongation of H3K27me3 mark.