Epigenomic analysis of Atrx deficiency in murine glioma cells of orgin [H3.3 ChIP]

The chromatin regulator ATRX is inactivated in large subsets of adult and pediatric glioma. Whether and how ATRX deficiency promotes oncogenesis by epigenomic dysregulation remains unclear. We found that Atrx loss, especially when coupled with Tp53 inactivation, promoted cell motility and modulated differentiation state in primary murine neuroepithelial progenitors, recapitulating characteristic disease phenotypes and molecular features. Moreover, Atrx deficiency induced widespread shifts in chromatin accessibility, histone composition, and gene transcription at vacant Atrx binding sites distributed across the genome. Finally, target genes mediating Atrx-deficient phenotypes in vitro exhibited similarly selective misexpression in ATRX-mutant human glioma tissues and cell lines. These findings demonstrate that, in appropriate physiological contexts, ATRX deficiency and its epigenomic sequelae are sufficient to induce disease-defining oncogenic phenotypes. Examination of H3.3 compositional changes genome-wide arising in the setting of Atrx deficiency in murine neuroepithelial progenitor cells (NPCs)