Distinct transcriptional outputs associated with mono- and di-methylated histone H3 arginine 2

Dimethylation of histone H3 arginine 2 (H3R2me2) maintains transcriptional silencing by inhibiting Set-1 mediated trimethylation of H3K4. Here we demonstrate that arginine 2 is also monomethylated (H3R2me1) in yeast but that its functional characteristics are distinct from H3R2me2: (a) H3R2me1 does not inhibit H3K4 methylation, (b) it is present throughout the coding region of genes and (c) it correlates with active transcription. Collectively, these results indicate that different H3R2 methylated states have defined roles in gene expression. hIP-chip analysis was performed to determine the genomic distribution of histone modifications H3R2me1, H3R2me2a, H3K4me3, H3K36me3, and H3K79me3 in the BY4741 yeast strain. ChIP samples were amplified, labelled, and hybridized to 50-mer tiling arrays covering the entire yeast genome at a 64 bp resolution.