Genome-wide Analyses of Histone H3 Methylation in a Polycomb Repressive Complex 2 Gene Mutant of Physcomitrella patens

Abstract

Polycomb repressive complex 2 (PRC2) trimethylates lysine 27 of histone H3 and mediates mitotically stable repression of target genes that are critical for developmental patterning and growth control in animals and plants. Here, we analyzed the genome-wide distribution pattern of H3K27me3 in the wild type and deletion mutant of the Physcomitrella patens CURLY LEAF (PpCLF) gene, which encodes a component of PRC2 (Okano et al. PNAS 2009; 106, 16321-26). In the wild type, H3K27me3 was enriched at more than 6,000 genes, which are ca 20% of all JGI gene models. In the ppclf mutant, we could not detect enrichment of H3K27me3 all over the genome. This result suggests that PRC2 containing PpCLF catalyzes trimethylation of H3K27 almost exclusively in P. patens. In addition, we are examining the genome-wide profiling of H3K4me3 and gene expression in the wild type and ppclf mutant. We will also present and discuss the relationship among H3K27me3, H3K4me3 and transcription.