Targeted proteolysis of the histone H3 tail facilitates epigenetic reprogramming during differentiation

Though limited proteolysis of the histone H3 N-terminal tail (H3NT) is frequently observed during mammalian differentiation, however the specific genomic sites targeted for H3NT proteolysis and their functional significance of H3NT cleavage remain unknown.We used genome wide Chip-seq (ChIPac-Seq) approaches to an established cell model of osteoclast differentiation. We discovered that H3NT proteolysis is selectively targeted near transcription start sites of a small group of genes and that most of these H3NT-cleaved genes are epigenetically regulated during osteoclastogenesis.We also discovered that the principal H3NT protease of osteoclastogenesis is matrix metalloproteinase 9 (MMP-9).Abrogation of H3NT proteolysis impaired osteoclastogenic gene activation concomitant with defective osteoclast differentiation. In summary our results support the necessity of MMP-9-dependent H3NT proteolysis in the epigenetic reprogramming of gene pathways required for proficient osteoclastogenesis. Genome wide study on the effect of H3NT (histone H3 N-terminal tail) cleavage using a ChIPac_seq.