PHF2 maintains neural progenitor genome stability by preserving pericentric heterochromatin integrity (ChIP-Seq)

Heterochromatin stability is crucial for progenitor proliferation during development. It relays on the maintenance of local hubs of H3K9me. However, the mechanisms underlying the establishment of competent local levels of H3K9me remain poorly understood. To address this intriguing question, we used a neural stem cell (NSC) model to analyze the significance of the H3K9me2 demethylase PHF2, which is crucial for progenitor proliferation. Through mass spectroscopy and genome-wide assays, we uncovered that PHF2 interacts with heterochromatin components and it is enriched at pericentromeric heterochromatin (PcH) boundaries. This binding is essential for maintaining silenced the satellite repeats and to prevent DNA damage and genome instability. To do that, PHF2 balances H3K9me3 levels at these boundaries to ensure high H3K9me3 levels at satellite repeats. Mechanistically, we discover that while its catalytic and PHD domains are indispensable, the intrinsically disordered region within PHF2 is dispensable for stabilizing PcH. Altogether, our study sheds light on the intricate relationship between heterochromatin stability and progenitor proliferation during mammalian neurogenesis.