Unstable transcription factor RNAs are targets of H3K27 trimethylation. (A) The RNA stability percentile of genes with H3K27me3 binding sites is shown. The asterisks at the right of the plot indicate that the stabilities for the indicated group of cell type-specific RNAs are different than other RNAs in the data set (Mann–Whitney U-test). The heat maps at the right display the fraction of each category that is composed of transcription factors (TFs) and the significance of the enrichment. The H3K27me3 binding sites were derived from ChIP-seq of whole L3 larvae that were collected as part of the modENCODE project (Celniker et al. 2009). Genes were classed as having a binding site within 1 kb of their transcription start site (upstream [A]), within 1 kb of their transcription termination site (downstream [C]), or within the gene body itself, including both introns and exons (gene body [B]). We assigned genes to a methylation category based on the combination of regions that had a methylation binding site. Each gene is assigned to only one category. Numbers in parentheses indicate the number of genes in each category. We excluded the upstream–downstream (AC) category because of scarcity; only 10 genes fell into this category. (*) P < 0.05, (**) P < 10 × 10−10, (***) P < 10 × 10−40.
