DNA methylation influences human centromere positioning and function.

Maintaining the epigenetic identity of centromeres is essential to prevent genome instability. Centromeres are epigenetically defined by the histone H3 variant CENP-A. Prior work in human centromeres has shown that CENP-A is associated with regions of hypomethylated DNA located within large arrays of hypermethylated repeats, but the functional importance of these DNA methylation (DNAme) patterns remains poorly understood. To address this, we developed tools to perturb centromeric DNAme, revealing that it causally influences CENP-A positioning. We show that rapid loss of methylation results in increased binding of centromeric proteins and alterations in centromere architecture, leading to aneuploidy and reduced cell viability. We also demonstrate that gradual centromeric DNA demethylation prompts a process of cellular adaptation. Altogether, we find that DNAme causally influences CENP-A localization and centromere function, offering mechanistic insights into pathological alterations of centromeric DNAme.